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<!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="datetime_functions">
<title>Impala Date and Time Functions</title>
<titlealts audience="PDF">
<navtitle>Date and Time Functions</navtitle>
</titlealts>
<prolog>
<metadata>
<data name="Category" value="Impala"/>
<data name="Category" value="Impala Functions"/>
<data name="Category" value="SQL"/>
<data name="Category" value="Data Analysts"/>
<data name="Category" value="Developers"/>
<data name="Category" value="Dates and Times"/>
<data name="Category" value="Querying"/>
</metadata>
</prolog>
<conbody>
<p>
The underlying Impala data types for date and time data are <codeph>TIMESTAMP</codeph> and
<codeph>DATE</codeph>.
</p>
<p rev="2.2.0">
Some of the date/time functions are affected by the setting of the
<codeph>&#8209;&#8209;use_local_tz_for_unix_timestamp_conversions</codeph> startup flag
for the <cmdname>impalad</cmdname> daemon:
<ul>
<li>
The setting is off by default, meaning that functions such as
<codeph>FROM_UNIXTIME()</codeph> and <codeph>UNIX_TIMESTAMP()</codeph> consider the
input values to always represent the UTC time zone.
</li>
<li>
The setting also applies when you <codeph>CAST()</codeph> a <codeph>BIGINT</codeph>
value to <codeph>TIMESTAMP</codeph>, or a <codeph>TIMESTAMP</codeph> value to
<codeph>BIGINT</codeph>. When this setting is enabled, these functions and operations
convert to and from values representing the local time zone. See
<xref
href="impala_timestamp.xml#timestamp"/> for details about how Impala
handles time zone considerations for the <codeph>TIMESTAMP</codeph> data type.
</li>
</ul>
</p>
<p>
<b>Function reference:</b>
</p>
<p>
Impala supports the following date and time functions:
</p>
<ul>
<li>
<xref href="#datetime_functions/add_months">ADD_MONTHS</xref>
</li>
<li>
<xref href="#datetime_functions/adddate">ADDDATE</xref>
</li>
<li>
<xref href="#datetime_functions/current_date">CURRENT_DATE</xref>
</li>
<li>
<xref href="#datetime_functions/current_timestamp"
>CURRENT_TIMESTAMP</xref>
</li>
<li>
<xref href="#datetime_functions/date_add">DATE_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/date_part">DATE_PART</xref>
</li>
<li>
<xref href="#datetime_functions/date_sub">DATE_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/date_trunc">DATE_TRUNC</xref>
</li>
<li>
<xref href="#datetime_functions/datediff">DATEDIFF</xref>
</li>
<li>
<xref href="#datetime_functions/day">DAY</xref>
</li>
<li>
<xref href="#datetime_functions/dayname">DAYNAME</xref>
</li>
<li>
<xref href="#datetime_functions/dayofweek">DAYOFWEEK</xref>
</li>
<li>
<xref href="#datetime_functions/dayofyear">DAYOFYEAR</xref>
</li>
<li>
<xref href="#datetime_functions/days_add">DAYS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/days_sub">DAYS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/extract">EXTRACT</xref>
</li>
<li>
<xref href="#datetime_functions/from_timestamp">FROM_TIMESTAMP</xref>
</li>
<li>
<xref href="#datetime_functions/from_unixtime">FROM_UNIXTIME</xref>
</li>
<li>
<xref href="#datetime_functions/from_utc_timestamp"
>FROM_UTC_TIMESTAMP</xref>
</li>
<li>
<xref href="#datetime_functions/hour">HOUR</xref>
</li>
<li>
<xref href="#datetime_functions/hours_add">HOURS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/hours_sub">HOURS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/int_months_between"
>INT_MONTHS_BETWEEN</xref>
</li>
<li>
<xref href="#datetime_functions/microseconds_add"
>MICROSECONDS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/microseconds_sub"
>MICROSECONDS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/millisecond">MILLISECOND</xref>
</li>
<li>
<xref href="#datetime_functions/milliseconds_add"
>MILLISECONDS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/milliseconds_sub"
>MILLISECONDS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/minute">MINUTE</xref>
</li>
<li>
<xref href="#datetime_functions/minutes_add">MINUTES_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/minutes_sub">MINUTES_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/month">MONTH</xref>
</li>
<li>
<xref href="#datetime_functions/month">MONTHNAME</xref>
</li>
<li>
<xref href="#datetime_functions/monthname">MONTHS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/months_between">MONTHS_BETWEEN</xref>
</li>
<li>
<xref href="#datetime_functions/months_sub">MONTHS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/nanoseconds_add">NANOSECONDS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/nanoseconds_sub">NANOSECONDS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/next_day">NEXT_DAY</xref>
</li>
<li>
<xref href="#datetime_functions/now">NOW</xref>
</li>
<li>
<xref href="#datetime_functions/quarter">QUARTER</xref>
</li>
<li>
<xref href="#datetime_functions/second">SECOND</xref>
</li>
<li>
<xref href="#datetime_functions/seconds_add">SECONDS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/seconds_sub">SECONDS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/subdate">SUBDATE</xref>
</li>
<li>
<xref href="#datetime_functions/timeofday">TIMEOFDAY</xref>
</li>
<li>
<xref href="#datetime_functions/timestamp_cmp">TIMESTAMP_CMP</xref>
</li>
<li>
<xref href="#datetime_functions/to_date">TO_DATE</xref>
</li>
<li>
<xref href="#datetime_functions/to_timestamp">TO_TIMESTAMP</xref>
</li>
<li>
<xref href="#datetime_functions/to_utc_timestamp"
>TO_UTC_TIMESTAMP</xref>
</li>
<li>
<xref href="#datetime_functions/trunc">TRUNC</xref>
</li>
<li>
<xref href="#datetime_functions/unix_timestamp">UNIX_TIMESTAMP</xref>
</li>
<li>
<xref href="#datetime_functions/utc_timestamp">UTC_TIMESTAMP</xref>
</li>
<li>
<xref href="#datetime_functions/weekofyear">WEEKOFYEAR</xref>
</li>
<li>
<xref href="#datetime_functions/weeks_add">WEEKS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/weeks_sub">WEEKS_SUB</xref>
</li>
<li>
<xref href="#datetime_functions/year">YEAR</xref>
</li>
<li>
<xref href="#datetime_functions/years_add">YEARS_ADD</xref>
</li>
<li>
<xref href="#datetime_functions/years_sub">YEARS_SUB</xref>
</li>
</ul>
<dl>
<dlentry rev="1.4.0" id="add_months">
<dt>
ADD_MONTHS(TIMESTAMP / DATE date, INT months), ADD_MONTHS(TIMESTAMP / DATE date,
BIGINT months)
</dt>
<dd>
<b>Purpose:</b> Adds <varname>months</varname> to <varname>date</varname> and returns
the new date value.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
Same as
<codeph><xref href="#datetime_functions/months_add"
>MONTHS_ADD()</xref></codeph>.
Available in Impala 1.4 and higher. For compatibility when porting code with vendor
extensions.
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="adddate">
<dt>
ADDDATE(TIMESTAMP / DATE date, INT / BIGINT days)
</dt>
<dd>
<b>Purpose:</b> Adds <varname>days</varname> to <varname>date</varname> and returns
the new date value.
<p>
The <varname>days</varname> value can be negative, which gives the same result as
the <codeph>SUBDATE()</codeph> function.
</p>
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
</dd>
</dlentry>
<dlentry id="current_date">
<dt>
CURRENT_DATE()
</dt>
<dd>
<b>Purpose:</b> Returns the current date.
<p>
Any references to the <codeph>CURRENT_DATE()</codeph> function are evaluated at the
start of a query. All calls to <codeph>CURRENT_DATE()</codeph> within the same query
return the same value, and the value does not depend on how long the query takes.
</p>
<p>
<b>Return type:</b> <codeph>DATE</codeph>
</p>
</dd>
</dlentry>
<dlentry id="current_timestamp">
<dt>
CURRENT_TIMESTAMP()
</dt>
<dd>
<b>Purpose:</b> Alias for the <codeph>NOW()</codeph> function.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry id="date_add">
<dt>
DATE_ADD(TIMESTAMP / DATE date, INT / BIGINT days), DATE_ADD(TIMESTAMP / DATE date,
interval_expression)
</dt>
<dd>
<b>Purpose:</b> Adds a specified number of days to the <varname>date</varname>
argument.
</dd>
<dd>
With an <codeph>INTERVAL</codeph> expression as the second argument, you can calculate
a delta value using other units such as weeks, years, hours, seconds, and so on; see
<xref
href="impala_timestamp.xml#timestamp"/> for details.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p>
The following examples show the shorthand notation of an <codeph>INTERVAL</codeph>
expression, instead of specifying the precise number of days. The
<codeph>INTERVAL</codeph> notation also lets you work with units smaller than a
single day.
</p>
<codeblock>
select now() as right_now, date_add(now(), interval 3 weeks) as in_3_weeks;
+-------------------------------+-------------------------------+
| right_now | in_3_weeks |
+-------------------------------+-------------------------------+
| 2016-05-20 11:05:39.173331000 | 2016-06-10 11:05:39.173331000 |
+-------------------------------+-------------------------------+
select now() as right_now, date_add(now(), interval 6 hours) as in_6_hours;
+-------------------------------+-------------------------------+
| right_now | in_6_hours |
+-------------------------------+-------------------------------+
| 2016-05-20 11:13:51.492536000 | 2016-05-20 17:13:51.492536000 |
+-------------------------------+-------------------------------+
</codeblock>
<p>
Like all date/time functions that deal with months, <codeph>date_add()</codeph>
handles nonexistent dates past the end of a month by setting the date to the last
day of the month. The following example shows how the nonexistent date April 31st is
normalized to April 30th:
</p>
<codeblock>
select date_add(cast('2016-01-31' as timestamp), interval 3 months) as 'april_31st';
+---------------------+
| april_31st |
+---------------------+
| 2016-04-30 00:00:00 |
+---------------------+
</codeblock>
</dd>
</dlentry>
<dlentry>
<dt>
DATE_CMP(DATE date1, DATE date2)
</dt>
<dd>
<b>Purpose:</b> Compares <varname>date1</varname> and <varname>date2</varname> and
returns:
<ul>
<li>
<codeph>0</codeph> if the dates are identical.
</li>
<li>
1 if <varname>date1</varname> > <varname>date2</varname>.
</li>
<li>
-1 if <varname>date1</varname> &lt; <varname>date2</varname>.
</li>
<li>
<codeph>NULL</codeph> if <varname>date1</varname> or <varname>date2</varname> is
<codeph>NULL</codeph>.
</li>
</ul>
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="2.0.0" id="date_part">
<dt>
DATE_PART(STRING part, TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Similar to
<xref
href="impala_datetime_functions.xml#datetime_functions/extract"
><codeph>EXTRACT()</codeph></xref>,
with the argument order reversed. Supports the same date and time units as
<codeph>EXTRACT()</codeph>. For compatibility with SQL code containing vendor
extensions.
<p>
<b>Return type:</b> <codeph>BIGINT</codeph>
</p>
</dd>
</dlentry>
<dlentry id="date_sub">
<dt>
DATE_SUB(TIMESTAMP startdate, INT days), DATE_SUB(TIMESTAMP startdate,
interval_expression)
</dt>
<dd>
<b>Purpose:</b> Subtracts a specified number of days from a <codeph>TIMESTAMP</codeph>
value. With an <codeph>INTERVAL</codeph> expression as the second argument, you can
calculate a delta value using other units such as weeks, years, hours, seconds, and so
on; see <xref href="impala_timestamp.xml#timestamp"/> for details.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p conref="../shared/impala_common.xml#common/example_blurb"/>
<p>
The following example shows the simplest usage, of subtracting a specified number of
days from a <codeph>TIMESTAMP</codeph> value:
</p>
<codeblock>
select now() as right_now, date_sub(now(), 7) as last_week;
+-------------------------------+-------------------------------+
| right_now | last_week |
+-------------------------------+-------------------------------+
| 2016-05-20 11:21:30.491011000 | 2016-05-13 11:21:30.491011000 |
+-------------------------------+-------------------------------+
</codeblock>
<p>
The following examples show the shorthand notation of an <codeph>INTERVAL</codeph>
expression, instead of specifying the precise number of days. The
<codeph>INTERVAL</codeph> notation also lets you work with units smaller than a
single day.
</p>
<codeblock>
select now() as right_now, date_sub(now(), interval 3 weeks) as 3_weeks_ago;
+-------------------------------+-------------------------------+
| right_now | 3_weeks_ago |
+-------------------------------+-------------------------------+
| 2016-05-20 11:23:05.176953000 | 2016-04-29 11:23:05.176953000 |
+-------------------------------+-------------------------------+
select now() as right_now, date_sub(now(), interval 6 hours) as 6_hours_ago;
+-------------------------------+-------------------------------+
| right_now | 6_hours_ago |
+-------------------------------+-------------------------------+
| 2016-05-20 11:23:35.439631000 | 2016-05-20 05:23:35.439631000 |
+-------------------------------+-------------------------------+
</codeblock>
<p>
Like all date/time functions that deal with months, <codeph>date_add()</codeph>
handles nonexistent dates past the end of a month by setting the date to the last
day of the month. The following example shows how the nonexistent date April 31st is
normalized to April 30th:
</p>
<codeblock>
select date_sub(cast('2016-05-31' as timestamp), interval 1 months) as 'april_31st';
+---------------------+
| april_31st |
+---------------------+
| 2016-04-30 00:00:00 |
+---------------------+
</codeblock>
</dd>
</dlentry>
<dlentry rev="2.11.0 IMPALA-5317" id="date_trunc">
<dt>
DATE_TRUNC(STRING unit, TIMESTAMP / DATE ts)
</dt>
<dd>
<b>Purpose:</b> Returns the <varname>ts</varname> value truncated to the specified
<varname>unit</varname>.
<p>
<b>Argument:</b> The <codeph>unit</codeph> argument is not case-sensitive. This
argument string can be one of:
</p>
<table frame="all" rowsep="1" colsep="1" id="table_ucy_trp_p3b">
<tgroup cols="3" align="left">
<colspec colname="c1" colnum="1" colwidth="1*"/>
<colspec colname="c2" colnum="2" colwidth="1.28*"/>
<colspec colname="c3" colnum="3" colwidth="1.66*"/>
<thead>
<row>
<entry>
Unit
</entry>
<entry>
Supported for TIMESTAMP
</entry>
<entry>
Supported for DATE
</entry>
</row>
</thead>
<tbody>
<row>
<entry>
<codeph>'MICROSECONDS'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'MILLISECONDS'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'SECOND'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'MINUTE'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'HOUR'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'DAY'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'WEEK'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'MONTH'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'YEAR'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'DECADE'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'CENTURY'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'MILLENNIUM'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
</tbody>
</tgroup>
</table>
<p conref="../shared/impala_common.xml#common/added_in_2110"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
Although this function is similar to calling <codeph>TRUNC()</codeph> with a
<codeph>TIMESTAMP</codeph> or <codeph>DATE</codeph> argument, the order of arguments
and the recognized units are different between <codeph>TRUNC()</codeph> and
<codeph>DATE_TRUNC()</codeph>. Therefore, these functions are not interchangeable.
</p>
<p>
This function is typically used in <codeph>GROUP BY</codeph> queries to aggregate
results from the same hour, day, week, month, quarter, and so on. You can also use
this function in an <codeph>INSERT ... SELECT</codeph> into a partitioned table to
divide <codeph>TIMESTAMP</codeph> or <codeph>DATE</codeph> values into the correct
partition.
</p>
<p>
<b>Return type:</b>
<ul>
<li>
<codeph>TIMESTAMP</codeph> if the second argument, <varname>ts</varname>, is
<codeph>TIMESTAMP</codeph>.
</li>
<li>
<codeph>DATE</codeph> if the second argument, <varname>ts</varname>, is
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p>
<b>Examples:</b>
</p>
<p>
<codeph>DATE_TRUNC('HOUR', NOW())</codeph> returns <codeph>2017-12-05
13:00:00</codeph>.
</p>
<p>
<codeph>DATE_TRUNC('MILLENNIUM', DATE'2019-08-02')</codeph> returns
<codeph>2001-01-01</codeph>.
</p>
</dd>
</dlentry>
<dlentry id="datediff">
<dt>
DATEDIFF(TIMESTAMP / DATE enddate, TIMESTAMP / DATE startdate)
</dt>
<dd>
<b>Purpose:</b> Returns the number of days from <varname>startdate</varname> to
<varname>enddate</varname>.
<p>
If <varname>enddate</varname> > <varname>startdate</varname>, the return value is
positive.
</p>
<p>
If <varname>enddate</varname> &lt; <varname>startdate</varname>, the return value is
negative.
</p>
<p>
If <varname>enddate</varname> = <varname>startdate</varname>, the return value is
zero.
</p>
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
<p>
<b>Usage notes:</b>
</p>
<p>
The time portions of the <varname>enddate</varname> and <varname>startdate</varname>
values are ignored. For example, 11:59 PM on one day and 12:01 AM on the next day
represent a <codeph>DATEDIFF()</codeph> of -1 because the date/time values represent
different days, even though the <codeph>TIMESTAMP</codeph> values differ by only 2
minutes.
</p>
</dd>
</dlentry>
<dlentry id="day">
<dt>
DAY(TIMESTAMP / DATE date), DAYOFMONTH(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the day value from the <varname>date</varname> argument. The
value represents the day of the month, therefore is in the range 1-31, or less for
months without 31 days.
<p>
Returns <codeph>NULL</codeph> for nonexistent dates, e.g. <codeph>Feb 30</codeph>,
or misformatted date strings, e.g. <codeph>'1999-02-013'</codeph>.
</p>
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.2" id="dayname">
<dt>
DAYNAME(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the day name of the <varname>date</varname> argument. The
range of return values is <codeph>'Sunday'</codeph> to <codeph>'Saturday'</codeph>.
Used in report-generating queries, as an alternative to calling
<codeph>DAYOFWEEK()</codeph> and turning that numeric return value into a string using
a <codeph>CASE</codeph> expression.
<p>
<b>Return type:</b> <codeph>STRING</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.1" id="dayofweek">
<dt>
DAYOFWEEK(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the day field of the <varname>date</varname> arguement,
corresponding to the day of the week. The range of return values is 1 (Sunday) to 7
(Saturday).
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="dayofyear">
<dt>
DAYOFYEAR(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the day field from the <varname>date</varname> argument,
corresponding to the day of the year. The range of return values is 1 (January 1) to
366 (December 31 of a leap year).
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="days_add">
<dt>
DAYS_ADD(TIMESTAMP / DATE date, INT / BIGINT days)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>days</varname> added to
<varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="days_sub">
<dt>
DAYS_SUB(TIMESTAMP / DATE date, INT / BIGINT days)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>days</varname>
subtracted from <varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
</dd>
</dlentry>
<dlentry rev="1.4.0" id="extract">
<dt>
EXTRACT(TIMESTAMP / DATE ts, STRING unit), EXTRACT(unit FROM TIMESTAMP / DATE ts)
</dt>
<dd>
<b>Purpose:</b> Returns one of the numeric date or time fields, specified by
<varname>unit</varname>, from <varname>ts</varname>.
<p>
<b>Argument:</b> The <codeph>unit</codeph> argument value is not case-sensitive. The
<codeph>unit</codeph> string can be one of:
</p>
<p>
<table frame="all" rowsep="1" colsep="1" id="table_itt_ktp_p3b">
<tgroup cols="3" align="left">
<colspec colname="c1" colnum="1" colwidth="1*"/>
<colspec colname="c2" colnum="2" colwidth="1.28*"/>
<colspec colname="c3" colnum="3" colwidth="1.66*"/>
<thead>
<row>
<entry>
Unit
</entry>
<entry>
Supported for TIMESTAMP ts
</entry>
<entry>
Supported for DATE ts
</entry>
</row>
</thead>
<tbody>
<row>
<entry>
<codeph>'EPOCH'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'MILLISECOND'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'SECOND'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'MINUTE'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'HOUR'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
</row>
<row>
<entry>
<codeph>'DAY'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'MONTH'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'QUARTER'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
<row>
<entry>
<codeph>'YEAR'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
</row>
</tbody>
</tgroup>
</table>
</p>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
Typically used in <codeph>GROUP BY</codeph> queries to arrange results by hour, day,
month, and so on. You can also use this function in an <codeph>INSERT ...
SELECT</codeph> statement to insert into a partitioned table to split up
<codeph>TIMESTAMP</codeph> values into individual parts, if the partitioned table
has separate partition key columns representing year, month, day, and so on. If you
need to divide by more complex units of time, such as by week or by quarter, use the
<codeph>TRUNC()</codeph> function instead.
</p>
<p>
<b>Return type:</b> <codeph>BIGINT</codeph>
</p>
<p conref="../shared/impala_common.xml#common/example_blurb"/>
<codeph>EXTRACT(DAY FROM DATE'2019-08-17')</codeph> returns <codeph>17</codeph>.
<p>
If you specify <codeph>'MILLISECOND'</codeph> for the <varname>unit</varname>
argument, the function returns the seconds component and the milliseconds component.
</p>
<p>
<codeph>EXTRACT(CAST('2006-05-12 18:27:28.123456789' AS TIMESTAMP),
'MILLISECOND')</codeph> returns <codeph>28123</codeph>.
</p>
</dd>
</dlentry>
<dlentry id="from_timestamp" rev="2.3.0 IMPALA-2190">
<dt>
FROM_TIMESTAMP(TIMESTAMP datetime, STRING pattern), FROM_TIMESTAMP(STRING datetime,
STRING pattern)
</dt>
<dd>
<b>Purpose:</b> Converts a <codeph>TIMESTAMP</codeph> value into a string representing
the same value.
<p>
<b>Return type:</b> <codeph>STRING</codeph>
</p>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
The <codeph>FROM_TIMESTAMP()</codeph> function provides a flexible way to convert
<codeph>TIMESTAMP</codeph> values into arbitrary string formats for reporting
purposes.
</p>
<p>
Because Impala implicitly converts string values into <codeph>TIMESTAMP</codeph>,
you can pass date/time values represented as strings (in the standard
<codeph>yyyy-MM-dd HH:mm:ss.SSS</codeph> format) to this function. The result is a
string using different separator characters, order of fields, spelled-out month
names, or other variation of the date/time string representation.
</p>
<p>
The allowed tokens for the pattern string are the same as for the
<codeph>FROM_UNIXTIME()</codeph> function.
</p>
</dd>
</dlentry>
<dlentry id="from_unixtime">
<dt>
FROM_UNIXTIME(BIGINT unixtime [, STRING pattern])
</dt>
<dd>
<b>Purpose:</b> Converts the number of seconds from the Unix epoch to the specified
time into a string in the local time zone.
<p>
<b>Return type:</b> <codeph>STRING</codeph>
</p>
<p rev="1.3.0">
The <varname>pattern</varname> string supports the following subset of Java
SimpleDateFormat.
</p>
<table frame="all"
rowsep="1" colsep="1" id="table_dzg_zpm_1jb">
<tgroup cols="2" align="left">
<thead>
<row>
<entry>
Pattern
</entry>
<entry>
Description
</entry>
</row>
</thead>
<tbody>
<row>
<entry>
<codeph>y</codeph>
</entry>
<entry>
Year
</entry>
</row>
<row>
<entry>
<codeph>M</codeph>
</entry>
<entry>
Month
</entry>
</row>
<row>
<entry>
<codeph>d</codeph>
</entry>
<entry>
Day
</entry>
</row>
<row>
<entry>
<codeph>H</codeph>
</entry>
<entry>
Hour
</entry>
</row>
<row>
<entry>
<codeph>m</codeph>
</entry>
<entry>
Minute
</entry>
</row>
<row>
<entry>
<codeph>s</codeph>
</entry>
<entry>
Second
</entry>
</row>
<row>
<entry>
<codeph>S</codeph>
</entry>
<entry>
Fractional second
</entry>
</row>
<row>
<entry>
<codeph>+/-hh:mm</codeph>
</entry>
<entry>
Time zone offset
</entry>
</row>
<row>
<entry>
<codeph>+/-hhmm</codeph>
</entry>
<entry>
Time zone offset
</entry>
</row>
<row>
<entry>
<codeph>+/-hh</codeph>
</entry>
<entry>
Time zone offset
</entry>
</row>
</tbody>
</tgroup>
</table>
<p>
The following rules apply to the <varname>pattern</varname> string:
</p>
<ul>
<li>
The <varname>pattern</varname> string is case-sensitive.
</li>
<li>
All fields are variable length, and thus must use separators to specify the
boundaries of the fields, with the exception of the time zone values.
</li>
<li>
Time zone offset formats must be at the end of the <varname>pattern</varname>
string.
</li>
<li>
Formatting character groups can appear in any order along with any separators
except for the time zone offset. For example:
<ul>
<li>
<codeph>yyyy/MM/dd</codeph>
</li>
<li>
<codeph>dd-MMM-yy</codeph>
</li>
<li>
<codeph>(dd)(MM)(yyyy) HH:mm:ss</codeph>
</li>
<li>
<codeph>yyyy-MM-dd HH:mm:ss+hh:mm</codeph>
</li>
</ul>
</li>
</ul>
<p rev="1.3.0">
In Impala 1.3 and later, you can switch the order of elements, use alternative
separator characters, and use a different number of placeholders for each unit.
Adding more instances of <codeph>y</codeph>, <codeph>d</codeph>, <codeph>H</codeph>,
and so on produces output strings zero-padded to the requested number of characters.
The exception is <codeph>M</codeph> for months, where <codeph>M</codeph> produces a
non-padded value such as <codeph>3</codeph>, <codeph>MM</codeph> produces a
zero-padded value such as <codeph>03</codeph>, <codeph>MMM</codeph> produces an
abbreviated month name such as <codeph>Mar</codeph>, and sequences of 4 or more
<codeph>M</codeph> are not allowed.
</p>
<p rev="1.3.0">
A date string including all fields could be <codeph>'yyyy-MM-dd
HH:mm:ss.SSSSSS'</codeph>, <codeph>'dd/MM/yyyy HH:mm:ss.SSSSSS'</codeph>,
<codeph>'MMM dd, yyyy HH.mm.ss (SSSSSS)'</codeph> or other combinations of
placeholders and separator characters.
</p>
<p
conref="../shared/impala_common.xml#common/y2k38"/>
<p
conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p
conref="../shared/impala_common.xml#common/timezone_conversion_caveat"
/>
</dd>
</dlentry>
<dlentry id="from_utc_timestamp">
<dt>
FROM_UTC_TIMESTAMP(TIMESTAMP ts, STRING timezone)
</dt>
<dd>
<b>Purpose:</b> Converts a specified UTC timestamp value into the appropriate value
for a specified time zone.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
<p>
<b>Usage notes:</b> Often used to translate UTC time zone data stored in a table
back to the local date and time for reporting. The opposite of the
<codeph>TO_UTC_TIMESTAMP()</codeph> function.
</p>
<p conref="../shared/impala_common.xml#common/current_timezone_tip"
/>
<p>
See discussion of time zones in
<xref
href="impala_timestamp.xml#timestamp"/> for information about
using this function for conversions between the local time zone and UTC.
</p>
</dd>
</dlentry>
<dlentry id="hour">
<dt>
HOUR(TIMESTAMP ts)
</dt>
<dd>
<b>Purpose:</b> Returns the hour field from a <codeph>TIMESTAMP</codeph> field.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="hours_add">
<dt>
HOURS_ADD(TIMESTAMP date, INT hours), HOURS_ADD(TIMESTAMP date, BIGINT hours)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time plus some number of hours.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="hours_sub">
<dt>
HOURS_SUB(TIMESTAMP date, INT hours), HOURS_SUB(TIMESTAMP date, BIGINT hours)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time minus some number of hours.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="2.3.0" id="int_months_between">
<dt>
INT_MONTHS_BETWEEN(TIMESTAMP / DATE enddate, TIMESTAMP / DATE startdate)
</dt>
<dd>
<b>Purpose:</b> Returns the number of months from <varname>startdate</varname> to
<varname>enddate</varname>, representing only the full months that passed.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
<p conref="../shared/impala_common.xml#common/added_in_230"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
Typically used in business contexts, for example to determine whether a specified
number of months have passed or whether some end-of-month deadline was reached.
</p>
<p>
The method of determining the number of elapsed months includes some special
handling of months with different numbers of days that creates edge cases for dates
between the 28th and 31st days of certain months. See
<codeph>MONTHS_BETWEEN()</codeph> for details. The
<codeph>INT_MONTHS_BETWEEN()</codeph> result is essentially the
<codeph>FLOOR()</codeph> of the <codeph>MONTHS_BETWEEN()</codeph> result.
</p>
<p>
If either value is <codeph>NULL</codeph>, which could happen for example when
converting a nonexistent date string such as <codeph>'2015-02-29'</codeph> to a
<codeph>TIMESTAMP</codeph>, the result is also <codeph>NULL</codeph>.
</p>
<p>
If the first argument represents an earlier time than the second argument, the
result is negative.
</p>
</dd>
</dlentry>
<dlentry id="last_day" rev="2.9.0 IMPALA-5316">
<dt>
LAST_DAY(TIMESTAMP / DATE ts)
</dt>
<dd>
<b>Purpose:</b> Returns the beginning of the last calendar day in the same month of
<varname>ts</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
Returns <codeph>TIMESTAMP</codeph> if <varname>ts</varname> is of the
<codeph>TIMESTAMP</codeph> type.
</li>
<li>
Returns <codeph>DATE</codeph> if <varname>ts</varname> is of the
<codeph>DATE</codeph> type.
</li>
</ul>
</p>
<p conref="../shared/impala_common.xml#common/added_in_290"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
If the input argument does not represent a valid Impala <codeph>TIMESTAMP</codeph>
including both date and time portions, the function returns <codeph>NULL</codeph>.
For example, if the input argument is a string that cannot be implicitly cast to
<codeph>TIMESTAMP</codeph>, does not include a date portion, or is out of the
allowed range for Impala <codeph>TIMESTAMP</codeph> values, the function returns
<codeph>NULL</codeph>.
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="microseconds_add">
<dt>
MICROSECONDS_ADD(TIMESTAMP date, INT microseconds), MICROSECONDS_ADD(TIMESTAMP date,
BIGINT microseconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time plus some number of microseconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="microseconds_sub">
<dt>
MICROSECONDS_SUB(TIMESTAMP date, INT microseconds), MICROSECONDS_SUB(TIMESTAMP date,
BIGINT microseconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time minus some number of microseconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="IMPALA-1772 2.6.0" id="millisecond">
<dt>
MILLISECOND(TIMESTAMP ts)
</dt>
<dd>
<b>Purpose:</b> Returns the millisecond portion of a <codeph>TIMESTAMP</codeph> value.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
<p conref="../shared/impala_common.xml#common/added_in_250"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
The millisecond value is truncated, not rounded, if the <codeph>TIMESTAMP</codeph>
value contains more than 3 significant digits to the right of the decimal point.
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="milliseconds_add">
<dt>
MILLISECONDS_ADD(TIMESTAMP date, INT milliseconds), MILLISECONDS_ADD(TIMESTAMP date,
BIGINT milliseconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time plus some number of milliseconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="milliseconds_sub">
<dt>
MILLISECONDS_SUB(TIMESTAMP date, INT milliseconds), MILLISECONDS_SUB(TIMESTAMP date,
BIGINT milliseconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time minus some number of milliseconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry id="minute">
<dt>
MINUTE(TIMESTAMP date)
</dt>
<dd>
<b>Purpose:</b> Returns the minute field from a <codeph>TIMESTAMP</codeph> value.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="minutes_add">
<dt>
MINUTES_ADD(TIMESTAMP date, INT minutes), MINUTES_ADD(TIMESTAMP date, BIGINT minutes)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time plus some number of minutes.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="minutes_sub">
<dt>
MINUTES_SUB(TIMESTAMP date, INT minutes), MINUTES_SUB(TIMESTAMP date, BIGINT minutes)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time minus some number of minutes.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry id="month">
<dt>
MONTH(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the month field, represented as an integer, from the
<varname>date</varname> argument.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry id="monthname">
<dt>
MONTHNAME(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the month name of the <varname>date</varname> argument.
<p>
<b>Return type:</b> <codeph>STRING</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="months_add">
<dt>
MONTHS_ADD(TIMESTAMP / DATE date, INT / BIGINT months)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>months</varname> added
to <varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p>
<b>Usage notes:</b>
</p>
<p>
If <varname>date</varname> is the last day of a month, the return date will fall on
the last day of the target month, e.g. <codeph>MONTHS_ADD(DATE'2019-01-31',
1)</codeph> returns <codeph>DATE'2019-02-28'</codeph>.
</p>
</dd>
</dlentry>
<dlentry rev="2.3.0" id="months_between">
<dt>
MONTHS_BETWEEN(TIMESTAMP / DATE enddate, TIMESTAMP / DATE startdate)
</dt>
<dd>
<b>Purpose:</b> Returns the number of months from <varname>startdate</varname> to
<varname>enddate</varname>.
</dd>
<dd>
This result can include a fractional part representing extra days in addition to the
full months between the dates. The fractional component is computed by dividing the
difference in days by 31 (regardless of the month).
<p>
<b>Return type:</b> <codeph>DOUBLE</codeph>
</p>
<p conref="../shared/impala_common.xml#common/added_in_230"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
Typically used in business contexts, for example to determine whether a specified
number of months have passed or whether some end-of-month deadline was reached.
</p>
<p>
If the only consideration is the number of full months and any fractional value is
not significant, use <codeph>INT_MONTHS_BETWEEN()</codeph> instead.
</p>
<p>
The method of determining the number of elapsed months includes some special
handling of months with different numbers of days that creates edge cases for dates
between the 28th and 31st days of certain months.
</p>
<p>
If either value is <codeph>NULL</codeph>, which could happen for example when
converting a nonexistent date string such as <codeph>'2015-02-29'</codeph> to a
<codeph>TIMESTAMP</codeph>, the result is also <codeph>NULL</codeph>.
</p>
<p>
If the first argument represents an earlier time than the second argument, the
result is negative.
</p>
<p>
The time portion of the input arguements are ignored.
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="months_sub">
<dt>
MONTHS_SUB(TIMESTAMP / DATE date, INT / BIGINT months)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>months</varname>
subtracted from <varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p>
<b>Usage notes:</b>
</p>
<p>
If <varname>date</varname> is the last day of a month, the return date will fall on
the last day of the target month, e.g. <codeph>MONTHS_SUB(DATE'2019-02-28',
1)</codeph> returns <codeph>DATE'2019-01-31'</codeph>.
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="nanoseconds_add">
<dt>
NANOSECONDS_ADD(TIMESTAMP date, INT nanoseconds), NANOSECONDS_ADD(TIMESTAMP date,
BIGINT nanoseconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time plus some number of nanoseconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
<p conref="../shared/impala_common.xml#common/kudu_blurb"/>
<p
conref="../shared/impala_common.xml#common/kudu_timestamp_nanoseconds_caveat"
/>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="nanoseconds_sub">
<dt>
NANOSECONDS_SUB(TIMESTAMP date, INT nanoseconds), NANOSECONDS_SUB(TIMESTAMP date,
BIGINT nanoseconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time minus some number of nanoseconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
<p conref="../shared/impala_common.xml#common/kudu_blurb"/>
<p
conref="../shared/impala_common.xml#common/kudu_timestamp_nanoseconds_caveat"
/>
</dd>
</dlentry>
<dlentry id="next_day">
<dt>
NEXT_DAY(TIMESTAMP / DATE date, STRING weekday)
</dt>
<dd>
<b>Purpose:</b> Returns the date of the <varname>weekday</varname> that follows the
specified <varname>date</varname>.
<p>
<b>Argument:</b> The <varname>weekday</varname> is not case-sensitive.
</p>
<p>
The following values are accepted for <varname>weekday</varname>:
<codeph>"Sunday"</codeph>/<codeph>"Sun"</codeph>,
<codeph>"Monday"</codeph>/<codeph>"Mon"</codeph>,
<codeph>"Tuesday"</codeph>/<codeph>"Tue"</codeph>,
<codeph>"Wednesday"</codeph>/<codeph>"Wed"</codeph>,
<codeph>"Thursday"</codeph>/<codeph>"Thu"</codeph>,
<codeph>"Friday"</codeph>/<codeph>"Fri"</codeph>,
<codeph>"Saturday"</codeph>/<codeph>"Sat"</codeph>
</p>
<p>
<b>Return type:</b>
<ul>
<li>
Returns <codeph>TIMESTAMP</codeph> if <varname>date</varname> is of the
<codeph>TIMESTAMP</codeph> type.
</li>
<li>
Returns <codeph>DATE</codeph> if <varname>date</varname> is of the
<codeph>DATE</codeph> type.
</li>
</ul>
</p>
<p conref="../shared/impala_common.xml#common/example_blurb"/>
<p>
<codeph>NEXT_DAY('2013-12-25','Saturday')</codeph> returns <codeph>'2013-12-28
00:00:00'</codeph> which is the first Saturday after December 25, 2013.
</p>
</dd>
</dlentry>
<dlentry id="now">
<dt>
NOW()
</dt>
<dd>
<b>Purpose:</b> Returns the current date and time (in the local time zone) as a
<codeph>TIMESTAMP</codeph> value.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
To find a date/time value in the future or the past relative to the current date and
time, add or subtract an <codeph>INTERVAL</codeph> expression to the return value of
<codeph>NOW()</codeph>. See
<xref
href="impala_timestamp.xml#timestamp"/> for examples.
</p>
<p>
To produce a <codeph>TIMESTAMP</codeph> representing the current date and time that
can be shared or stored without interoperability problems due to time zone
differences, use the <codeph>TO_UTC_TIMESTAMP()</codeph> function and specify the
time zone of the server. When <codeph>TIMESTAMP</codeph> data is stored in UTC form,
any application that queries those values can convert them to the appropriate local
time zone by calling the inverse function, <codeph>FROM_UTC_TIMESTAMP()</codeph>.
</p>
<p conref="../shared/impala_common.xml#common/current_timezone_tip"/>
<p>
Any references to the <codeph>NOW()</codeph> function are evaluated at the start of
a query. All calls to <codeph>NOW()</codeph> within the same query return the same
value, and the value does not depend on how long the query takes.
</p>
</dd>
</dlentry>
<dlentry id="quarter">
<dt>
QUARTER(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the quarter in the input <varname>date</varname> argument as
an integer value, 1, 2, 3, or 4, where 1 represents January 1 through March 31.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry id="second">
<dt>
SECOND(TIMESTAMP date)
</dt>
<dd>
<b>Purpose:</b> Returns the second field from a <codeph>TIMESTAMP</codeph> value.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="seconds_add">
<dt>
SECONDS_ADD(TIMESTAMP date, INT seconds), SECONDS_ADD(TIMESTAMP date, BIGINT seconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time plus some number of seconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="seconds_sub">
<dt>
SECONDS_SUB(TIMESTAMP date, INT seconds), SECONDS_SUB(TIMESTAMP date, BIGINT seconds)
</dt>
<dd>
<b>Purpose:</b> Returns the specified date and time minus some number of seconds.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="subdate">
<dt>
SUBDATE(TIMESTAMP / DATE date, INT / BIGINT days)
</dt>
<dd>
<b>Purpose:</b> Subtracts <varname>days</varname> from <varname>date</varname> and
returns the new date value.
<p>
The <varname>days</varname> value can be negative, which gives the same result as
the <codeph>ADDDATE()</codeph> function.
</p>
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
</dd>
</dlentry>
<dlentry rev="2.3.0" id="timeofday">
<dt>
TIMEOFDAY()
</dt>
<dd>
<b>Purpose:</b> Returns a string representation of the current date and time,
according to the time of the local system, including any time zone designation.
<p>
<b>Return type:</b> <codeph>STRING</codeph>
</p>
<p conref="../shared/impala_common.xml#common/added_in_230"/>
<p>
<b>Usage notes:</b> The result value represents similar information as the
<codeph>now()</codeph> function, only as a <codeph>STRING</codeph> type and with
somewhat different formatting. For example, the day of the week and the time zone
identifier are included. This function is intended primarily for compatibility with
SQL code from other systems that also have a <codeph>timeofday()</codeph> function.
Prefer to use <codeph>now()</codeph> if practical for any new Impala code.
</p>
</dd>
</dlentry>
<dlentry rev="2.3.0" id="timestamp_cmp">
<dt>
TIMESTAMP_CMP(TIMESTAMP t1, TIMESTAMP t2)
</dt>
<dd>
<b>Purpose:</b> Tests if one <codeph>TIMESTAMP</codeph> value is newer than, older
than, or identical to another <codeph>TIMESTAMP</codeph>
<ul>
<li>
<p>
If the first argument represents a later point in time than the second argument,
the result is 1.
</p>
</li>
<li>
<p>
If the first argument represents an earlier point in time than the second
argument, the result is -1.
</p>
</li>
<li>
<p>
If the first and second arguments represent identical points in time, the result
is 0.
</p>
</li>
<li>
<p>
If either argument is <codeph>NULL</codeph>, the result is
<codeph>NULL</codeph>.
</p>
</li>
</ul>
<p>
<b>Return type:</b> <codeph>INT</codeph> (either -1, 0, 1, or <codeph>NULL</codeph>)
</p>
<p conref="../shared/impala_common.xml#common/added_in_230"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
<b>Usage notes:</b> A comparison function for <codeph>TIMESTAMP</codeph> values that
only tests whether the date and time increases, decreases, or stays the same.
Similar to the <codeph>SIGN()</codeph> function for numeric values.
</p>
</dd>
</dlentry>
<dlentry id="to_date">
<dt>
TO_DATE(TIMESTAMP ts)
</dt>
<dd>
<b>Purpose:</b> Returns a string representation of the date field from the
<varname>ts</varname> argument.
<p>
<b>Return type:</b> <codeph>STRING</codeph>
</p>
</dd>
</dlentry>
<dlentry id="to_timestamp" rev="2.3.0 IMPALA-2190">
<dt>
TO_TIMESTAMP(BIGINT unixtime), TO_TIMESTAMP(STRING date, STRING pattern)
</dt>
<dd>
<b>Purpose:</b> Converts an integer or string representing a date/time value into the
corresponding <codeph>TIMESTAMP</codeph> value.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
<p conref="../shared/impala_common.xml#common/added_in_230"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
An integer argument represents the number of seconds past the epoch (midnight on
January 1, 1970). It is the converse of the <codeph>UNIX_TIMESTAMP()</codeph>
function, which produces a <codeph>BIGINT</codeph> representing the number of
seconds past the epoch.
</p>
<p>
A string argument, plus another string argument representing the pattern, turns an
arbitrary string representation of a date and time into a true
<codeph>TIMESTAMP</codeph> value. The ability to parse many kinds of date and time
formats allows you to deal with temporal data from diverse sources, and if desired
to convert to efficient <codeph>TIMESTAMP</codeph> values during your ETL process.
Using <codeph>TIMESTAMP</codeph> directly in queries and expressions lets you
perform date and time calculations without the overhead of extra function calls and
conversions each time you reference the applicable columns.
</p>
<p conref="../shared/impala_common.xml#common/example_blurb"/>
<p>
The following examples demonstrate how to convert an arbitrary string representation
to <codeph>TIMESTAMP</codeph> based on a pattern string:
</p>
<codeblock>
select to_timestamp('Sep 25, 1984', 'MMM dd, yyyy');
+----------------------------------------------+
| to_timestamp('sep 25, 1984', 'mmm dd, yyyy') |
+----------------------------------------------+
| 1984-09-25 00:00:00 |
+----------------------------------------------+
select to_timestamp('1984/09/25', 'yyyy/MM/dd');
+------------------------------------------+
| to_timestamp('1984/09/25', 'yyyy/mm/dd') |
+------------------------------------------+
| 1984-09-25 00:00:00 |
+------------------------------------------+
</codeblock>
<p>
The following examples show how to convert a <codeph>BIGINT</codeph> representing
seconds past epoch into a <codeph>TIMESTAMP</codeph> value:
</p>
<codeblock>
-- One day past the epoch.
select to_timestamp(24 * 60 * 60);
+----------------------------+
| to_timestamp(24 * 60 * 60) |
+----------------------------+
| 1970-01-02 00:00:00 |
+----------------------------+
-- 60 seconds in the past.
select now() as 'current date/time',
unix_timestamp(now()) 'now in seconds',
to_timestamp(unix_timestamp(now()) - 60) as '60 seconds ago';
+-------------------------------+----------------+---------------------+
| current date/time | now in seconds | 60 seconds ago |
+-------------------------------+----------------+---------------------+
| 2017-10-01 22:03:46.885624000 | 1506895426 | 2017-10-01 22:02:46 |
+-------------------------------+----------------+---------------------+
</codeblock>
</dd>
</dlentry>
<dlentry id="to_utc_timestamp">
<dt>
TO_UTC_TIMESTAMP(TIMESTAMP ts, STRING timezone)
</dt>
<dd>
<b>Purpose:</b> Converts a specified timestamp value in a specified time zone into the
corresponding value for the UTC time zone.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
Often used in combination with the <codeph>now()</codeph> function, to translate
local date and time values to the UTC time zone for consistent representation on
disk. The opposite of the <codeph>FROM_UTC_TIMESTAMP()</codeph> function.
</p>
<p>
See discussion of time zones in
<xref
href="impala_timestamp.xml#timestamp"/> for information about
using this function for conversions between the local time zone and UTC.
</p>
<p conref="../shared/impala_common.xml#common/example_blurb"/>
<p>
The simplest use of this function is to turn a local date/time value to one with the
standardized UTC time zone. Because the time zone specifier is not saved as part of
the Impala <codeph>TIMESTAMP</codeph> value, all applications that refer to such
data must agree in advance which time zone the values represent. If different parts
of the ETL cycle, or different instances of the application, occur in different time
zones, the ideal reference point is to convert all <codeph>TIMESTAMP</codeph> values
to UTC for storage.
</p>
<codeblock>
select now() as 'Current time in California USA',
to_utc_timestamp(now(), 'PDT') as 'Current time in Greenwich UK';
+--------------------------------+-------------------------------+
| current time in california usa | current time in greenwich uk |
+--------------------------------+-------------------------------+
| 2016-06-01 15:52:08.980072000 | 2016-06-01 22:52:08.980072000 |
+--------------------------------+-------------------------------+
</codeblock>
<p>
Once a value is converted to the UTC time zone by
<codeph>TO_UTC_TIMESTAMP()</codeph>, it can be converted back to the local time zone
with <codeph>FROM_UTC_TIMESTAMP()</codeph>. You can combine these functions using
different time zone identifiers to convert a <codeph>TIMESTAMP</codeph> between any
two time zones. This example starts with a <codeph>TIMESTAMP</codeph> value
representing Pacific Daylight Time, converts it to UTC, and converts it to the
equivalent value in Eastern Daylight Time.
</p>
<codeblock>
select now() as 'Current time in California USA',
from_utc_timestamp
(
to_utc_timestamp(now(), 'PDT'),
'EDT'
) as 'Current time in New York, USA';
+--------------------------------+-------------------------------+
| current time in california usa | current time in new york, usa |
+--------------------------------+-------------------------------+
| 2016-06-01 18:14:12.743658000 | 2016-06-01 21:14:12.743658000 |
+--------------------------------+-------------------------------+
</codeblock>
</dd>
</dlentry>
<dlentry rev="1.4.0" id="trunc">
<dt id="trunc_timestamp">
TRUNC(TIMESTAMP / DATE ts, STRING unit)
</dt>
<dd>
<b>Purpose:</b> Returns the <varname>ts</varname> truncated to the
<varname>unit</varname> specified.
<p>
<b>Argument:</b> The <varname>unit</varname> argument is not case-sensitive. This
argument string can be one of:
</p>
<p>
<table frame="all" rowsep="1" colsep="1" id="table_evg_bhp_p3b">
<tgroup cols="4" align="left">
<colspec colname="c1" colnum="1" colwidth="1*"/>
<colspec colname="c2" colnum="2" colwidth="1*"/>
<colspec colname="c3" colnum="3" colwidth="1*"/>
<colspec colname="newCol4" colnum="4" colwidth="1*"/>
<thead>
<row>
<entry>
Unit
</entry>
<entry>
Supported for TIMESTAMP ts
</entry>
<entry>
Supported for DATE ts
</entry>
<entry>
Description
</entry>
</row>
</thead>
<tbody>
<row>
<entry>
<p>
<codeph>'SYYYY'</codeph>
</p>
<p>
<codeph>'YYYY'</codeph>
</p>
<p>
<codeph>'YEAR'</codeph>
</p>
<p>
<codeph>'SYEAR'</codeph>
</p>
<p>
<codeph>'YYY'</codeph>
</p>
<p>
<codeph>'YY'</codeph>
</p>
<p>
<codeph>'Y'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
<entry>
Year
</entry>
</row>
<row>
<entry>
<p>
<codeph>'Q'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
<entry>
Quarter
</entry>
</row>
<row>
<entry>
<p>
<codeph>'MONTH'</codeph>
</p>
<p>
<codeph>'MON'</codeph>
</p>
<p>
<codeph>'MM'</codeph>
</p>
<p>
<codeph>'RM'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
<entry>
Month
</entry>
</row>
<row>
<entry>
<p>
<codeph>'WW'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
<entry>
The most recent date that is the same day of the week as the first day of
the year
</entry>
</row>
<row>
<entry>
<p>
<codeph>'W'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
<entry>
The most recent date that is the same day of the week as the first day of
the month
</entry>
</row>
<row>
<entry>
<p>
<codeph>'DDD'</codeph>
</p>
<p>
<codeph>'DD'</codeph>
</p>
<p>
<codeph>'J'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
<entry>
Day
</entry>
</row>
<row>
<entry>
<p>
<codeph>'DAY'</codeph>
</p>
<p>
<codeph>'DY'</codeph>
</p>
<p>
<codeph>'D'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
Yes
</entry>
<entry>
Starting day of the week (Monday)
</entry>
</row>
<row>
<entry>
<p>
<codeph>'HH'</codeph>
</p>
<p>
<codeph>'HH12'</codeph>
</p>
<p>
<codeph>'HH24'</codeph>
</p>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
<entry>
Hour. A <codeph>TIMESTAMP</codeph> value truncated to the hour is always
represented in 24-hour notation, even for the <codeph>HH12</codeph>
argument string.
</entry>
</row>
<row>
<entry>
<codeph>'MI'</codeph>
</entry>
<entry>
Yes
</entry>
<entry>
No
</entry>
<entry>
Minute
</entry>
</row>
</tbody>
</tgroup>
</table>
</p>
<p>
<b>Added in:</b> The ability to truncate numeric values is new starting in
<keyword keyref="impala210_full"/>.
</p>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
The <codeph>TIMESTAMP</codeph> form is typically used in <codeph>GROUP BY</codeph>
queries to aggregate results from the same hour, day, week, month, quarter, and so
on. You can also use this function in an <codeph>INSERT ... SELECT</codeph> into a
partitioned table to divide <codeph>TIMESTAMP</codeph> values into the correct
partition.
</p>
<p>
<b>Return type:</b>
<ul>
<li>
<codeph>TIMESTAMP</codeph> if the first argument, <varname>ts</varname>, is
<codeph>TIMESTAMP</codeph>.
</li>
<li>
<codeph>DATE</codeph> if the first argument, <varname>ts</varname>, is
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p>
<b>Example:</b>
</p>
<p>
<codeph>TRUNC(DATE'2019-05-08','YEAR')</codeph> returns <codeph>2019-01-01</codeph>.
</p>
<p>
<codeph>TRUNC(DATE'2019-05-08', 'QUARTER')</codeph> returns
<codeph>2019-04-01</codeph>.
</p>
</dd>
</dlentry>
<dlentry id="unix_timestamp">
<dt>
UNIX_TIMESTAMP(), UNIX_TIMESTAMP(STRING datetime), UNIX_TIMESTAMP(STRING datetime,
STRING pattern), UNIX_TIMESTAMP(TIMESTAMP datetime)
</dt>
<dd>
<b>Purpose:</b> Returns a Unix time, which is a number of seconds elapsed since
'1970-01-01 00:00:00' UTC. If called with no argument, the current date and time is
converted to its Unix time. If called with arguments, the first argument represented
as the <codeph>TIMESTAMP</codeph> or <codeph>STRING</codeph> is converted to its Unix
time.
<p>
<b>Return type:</b> <codeph rev="2.2.0">BIGINT</codeph>
</p>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p rev="1.3.0">
See <codeph>FROM_UNIXTIME()</codeph> for details about the patterns you can use in
the <varname>pattern</varname> string to represent the position of year, month, day,
and so on in the <codeph>date</codeph> string. In Impala 1.3 and higher, you have
more flexibility to switch the positions of elements and use different separator
characters.
</p>
<p rev="2.2.3">
In <keyword keyref="impala223"/> and higher, you can include a trailing uppercase
<codeph>Z</codeph> qualifier to indicate <q>Zulu</q> time, a synonym for UTC.
</p>
<p rev="2.3.0">
In <keyword keyref="impala23_full"/> and higher, you can include a timezone offset
specified as minutes and hours, provided you also specify the details in the
<varname>pattern</varname> string argument. The offset is specified in the
<varname>pattern</varname> string as a plus or minus sign followed by
<codeph>hh:mm</codeph>, <codeph>hhmm</codeph>, or <codeph>hh</codeph>. The
<codeph>hh</codeph> must be lowercase, to distinguish it from the
<codeph>HH</codeph> represent hours in the actual time value. Currently, only
numeric timezone offsets are allowed, not symbolic names.
</p>
<p conref="../shared/impala_common.xml#common/y2k38"/>
<p
conref="../shared/impala_common.xml#common/datetime_function_chaining"/>
<p
conref="../shared/impala_common.xml#common/timezone_conversion_caveat"/>
<p conref="../shared/impala_common.xml#common/example_blurb"/>
<p>
The following examples show different ways of turning the same date and time into an
integer value. A <varname>pattern</varname> string that Impala recognizes by default
is interpreted as a UTC date and time. The trailing <codeph>Z</codeph> is a
confirmation that the timezone is UTC. If the date and time string is formatted
differently, a second argument specifies the position and units for each of the date
and time values.
</p>
<p>
The final two examples show how to specify a timezone offset of Pacific Daylight
Saving Time, which is 7 hours earlier than UTC. You can use the numeric offset
<codeph>-07:00</codeph> and the equivalent suffix of <codeph>-hh:mm</codeph> in the
pattern string, or specify the mnemonic name for the time zone in a call to
<codeph>TO_UTC_TIMESTAMP()</codeph>. This particular date and time expressed in PDT
translates to a different number than the same date and time expressed in UTC.
</p>
<codeblock rev="2.3.0">
-- 3 ways of expressing the same date/time in UTC and converting to an integer.
select unix_timestamp('2015-05-15 12:00:00');
+---------------------------------------+
| unix_timestamp('2015-05-15 12:00:00') |
+---------------------------------------+
| 1431691200 |
+---------------------------------------+
select unix_timestamp('2015-05-15 12:00:00Z');
+----------------------------------------+
| unix_timestamp('2015-05-15 12:00:00z') |
+----------------------------------------+
| 1431691200 |
+----------------------------------------+
select unix_timestamp
(
'May 15, 2015 12:00:00',
'MMM dd, yyyy HH:mm:ss'
) as may_15_month_day_year;
+-----------------------+
| may_15_month_day_year |
+-----------------------+
| 1431691200 |
+-----------------------+
-- 2 ways of expressing the same date and time but in a different timezone.
-- The resulting integer is different from the previous examples.
select unix_timestamp
(
'2015-05-15 12:00:00-07:00',
'yyyy-MM-dd HH:mm:ss-hh:mm'
) as may_15_year_month_day;
+-----------------------+
| may_15_year_month_day |
+-----------------------+
| 1431716400 |
+-----------------------+
select unix_timestamp
(to_utc_timestamp(
'2015-05-15 12:00:00',
'PDT')
) as may_15_pdt;
+------------+
| may_15_pdt |
+------------+
| 1431716400 |
+------------+
</codeblock>
</dd>
</dlentry>
<dlentry id="utc_timestamp" rev="2.10.0 IMPALA-3504">
<dt>
UTC_TIMESTAMP()
</dt>
<dd>
<b>Purpose:</b> Returns a <codeph>TIMESTAMP</codeph> corresponding to the current date
and time in the UTC time zone.
<p>
<b>Return type:</b> <codeph>TIMESTAMP</codeph>
</p>
<p conref="../shared/impala_common.xml#common/added_in_210"/>
<p conref="../shared/impala_common.xml#common/usage_notes_blurb"/>
<p>
Similar to the <codeph>NOW()</codeph> or <codeph>CURRENT_TIMESTAMP()</codeph>
functions, but does not use the local time zone as those functions do. Use
<codeph>UTC_TIMESTAMP()</codeph> to record <codeph>TIMESTAMP</codeph> values that
are interoperable with servers around the world, in arbitrary time zones, without
the need for additional conversion functions to standardize the time zone of each
value representing a date/time.
</p>
<p>
For working with date/time values represented as integer values, you can convert
back and forth between <codeph>TIMESTAMP</codeph> and <codeph>BIGINT</codeph> with
the <codeph>UNIX_MICROS_TO_UTC_TIMESTAMP()</codeph> and
<codeph>UTC_TO_UNIX_MICROS()</codeph> functions. The integer values represent the
number of microseconds since the Unix epoch (midnight on January 1, 1970).
</p>
<p conref="../shared/impala_common.xml#common/example_blurb"/>
<p>
The following example shows how <codeph>NOW()</codeph> and
<codeph>CURRENT_TIMESTAMP()</codeph> represent the current date/time in the local
time zone (in this case, UTC-7), while <codeph>utc_timestamp()</codeph> represents
the same date/time in the standardized UTC time zone:
</p>
<codeblock>
select now(), utc_timestamp();
+-------------------------------+-------------------------------+
| now() | utc_timestamp() |
+-------------------------------+-------------------------------+
| 2017-10-01 23:33:58.919688000 | 2017-10-02 06:33:58.919688000 |
+-------------------------------+-------------------------------+
select current_timestamp(), utc_timestamp();
+-------------------------------+-------------------------------+
| current_timestamp() | utc_timestamp() |
+-------------------------------+-------------------------------+
| 2017-10-01 23:34:07.400642000 | 2017-10-02 06:34:07.400642000 |
+-------------------------------+-------------------------------+
</codeblock>
</dd>
</dlentry>
<dlentry id="weekofyear">
<dt>
WEEK(TIMESTAMP / DATE date), WEEKOFYEAR(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the corresponding week (1-53) from the <varname>date</varname>
argument.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="weeks_add">
<dt>
WEEKS_ADD(TIMESTAMP / DATE date, INT / BIGINT weeks)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>weeks</varname> added to
<varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="weeks_sub">
<dt>
WEEKS_SUB(TIMESTAMP / DATE date, INT / BIGINT weeks)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>weeks</varname>
subtracted from <varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
</dd>
</dlentry>
<dlentry id="year">
<dt>
YEAR(TIMESTAMP / DATE date)
</dt>
<dd>
<b>Purpose:</b> Returns the year field from the <varname>date</varname> argument.
<p>
<b>Return type:</b> <codeph>INT</codeph>
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="years_add">
<dt>
YEARS_ADD(TIMESTAMP / DATE date, INT / BIGINT years)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>years</varname> added to
<varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p>
<b>Usage notes:</b>
</p>
<p>
If the equivalent date does not exist in the year of the result due to a leap year,
the date is changed to the last day of the appropriate month.
</p>
</dd>
</dlentry>
<dlentry rev="1.3.0" id="years_sub">
<dt>
YEARS_SUB(TIMESTAMP / DATE date, INT / BIGINT years)
</dt>
<dd>
<b>Purpose:</b> Returns the value with the number of <varname>years</varname>
subtracted from <varname>date</varname>.
<p>
<b>Return type:</b>
<ul>
<li>
If <varname>date</varname> is <codeph>TIMESTAMP</codeph>, returns
<codeph>TIMESTAMP</codeph>.
</li>
<li>
If <varname>date</varname> is <codeph>DATE</codeph>, returns
<codeph>DATE</codeph>.
</li>
</ul>
</p>
<p>
<b>Usage notes:</b>
</p>
<p>
If the equivalent date does not exist in the year of the result due to a leap year,
the date is changed to the last day of the appropriate month.
</p>
<p/>
</dd>
</dlentry>
</dl>
</conbody>
</concept>