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| <!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd"> |
| <concept id="date" rev="2.0.0"> |
| |
| <title>DATE Data Type</title> |
| |
| <titlealts audience="PDF"> |
| |
| <navtitle>DATE</navtitle> |
| |
| </titlealts> |
| |
| <prolog> |
| <metadata> |
| <data name="Category" value="Impala"/> |
| <data name="Category" value="Impala Data Types"/> |
| <data name="Category" value="SQL"/> |
| <data name="Category" value="Data Analysts"/> |
| <data name="Category" value="Developers"/> |
| <data name="Category" value="Dates and Times"/> |
| </metadata> |
| </prolog> |
| |
| <conbody> |
| |
| <p> Use the <codeph>DATE</codeph> data type to store date values. The |
| <codeph>DATE</codeph> type is supported for HBase, Text, Avro, and |
| Parquet. </p> |
| |
| <p> |
| <b>Range:</b> |
| </p> |
| |
| <p> 0001-01-01 to 9999-12-31 </p> |
| |
| <p> |
| <b>Literals and expressions:</b> |
| </p> |
| |
| <p> The <codeph>DATE</codeph> literals are in the form of |
| <codeph>DATE'YYYY-MM-DD'</codeph>. For examplep, <codeph>DATE |
| '2013-01-01'</codeph> |
| </p> |
| |
| <p> |
| <b>Parquet and Avro considerations:</b> |
| </p> |
| |
| <p> Parquet and Avro use <codeph>DATE</codeph> logical type for dates. The |
| <codeph>DATE</codeph> logical type annotates an <codeph>INT32</codeph> |
| that stores the number of days from the Unix epoch, January 1, 1970. This |
| representation introduces an interoperability issue between Impala and |
| older versions of Hive: </p> |
| |
| <p> If Hive versions lower than 3.1 wrote dates earlier than 1582-10-15 to a |
| Parquet or Avro table, those dates would be read back incorrectly by |
| Impala and vice versa. In Hive 3.1 and higher, this is no longer an issue. </p> |
| |
| <p> |
| <b>Explicit casting between DATE and other data types:</b> |
| </p> |
| |
| <p> |
| <codeph>DATE</codeph> type can only be converted to/from <codeph>DATE</codeph>, |
| <codeph>TIMESTAMP</codeph>, or <codeph>STRING</codeph> types as described below. |
| </p> |
| |
| <table id="table_ovw_zt1_p3b"> |
| <tgroup cols="3"> |
| <colspec colnum="1" colname="col1" colwidth="1*"/> |
| <colspec colname="newCol2" colnum="2" colwidth="1.09*"/> |
| <colspec colnum="3" colname="col2" colwidth="3.46*"/> |
| <thead> |
| <row> |
| <entry> |
| Cast from |
| </entry> |
| <entry> |
| Cast to |
| </entry> |
| <entry> |
| Result |
| </entry> |
| </row> |
| </thead> |
| <tbody> |
| <row> |
| <entry> |
| <codeph>TIMESTAMP</codeph> |
| </entry> |
| <entry> |
| <codeph>DATE</codeph> |
| </entry> |
| <entry> |
| The date component of the <codeph>TIMESTAMP</codeph> is returned, and the time of |
| the day component of the <codeph>TIMESTAMP</codeph> is ignored. |
| </entry> |
| </row> |
| <row> |
| <entry> |
| <codeph>STRING</codeph> |
| </entry> |
| <entry> |
| <codeph>DATE</codeph> |
| </entry> |
| <entry> |
| The <codeph>DATE</codeph> value of <codeph>yyyy-MM-dd</codeph> is returned. |
| |
| <p> |
| The <codeph>STRING</codeph> value must be in the <codeph>yyyy-MM-dd</codeph> or |
| <codeph>yyyy-MM-dd HH:mm:ss.SSSSSSSSS</codeph> pattern. |
| </p> |
| |
| |
| |
| <p> |
| If the time component is present in <codeph>STRING</codeph>, it is silently |
| ignored. |
| </p> |
| |
| |
| |
| <p> |
| If the <codeph>STRING</codeph> value does not match the above formats, an error |
| is returned. |
| </p> |
| </entry> |
| </row> |
| <row> |
| <entry> |
| <codeph>DATE</codeph> |
| </entry> |
| <entry> |
| <codeph>TIMESTAMP</codeph> |
| </entry> |
| <entry> |
| The year, month, and day of the <codeph>DATE</codeph> is returned along with the |
| time of day component set to <codeph>00:00:00</codeph>. |
| </entry> |
| </row> |
| <row> |
| <entry> |
| <codeph>DATE</codeph> |
| </entry> |
| <entry> |
| <codeph>STRING</codeph> |
| </entry> |
| <entry> |
| The <codeph>STRING</codeph> value, <codeph>'yyyy-MM-dd'</codeph>, is returned. |
| </entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </table> |
| |
| <p> |
| <b>Implicit casting between DATE and other types: </b> |
| </p> |
| |
| <p> |
| Implicit casting is supported: |
| </p> |
| |
| <ul> |
| <li> |
| From <codeph>STRING</codeph> to <codeph>DATE</codeph> if the source |
| <codeph>STRING</codeph> value is in the <codeph>yyyy-MM-dd</codeph> or |
| <codeph>yyyy-MM-dd HH:mm:ss.SSSSSSSSS</codeph> pattern. |
| </li> |
| |
| <li> |
| From <codeph>DATE</codeph> to <codeph>TIMESTAMP</codeph>. |
| </li> |
| </ul> |
| |
| <p> |
| <b>Added in:</b> |
| </p> |
| |
| <p> |
| The <codeph>DATE</codeph> type is available in Impala 3.3 and higher. |
| </p> |
| |
| </conbody> |
| |
| </concept> |