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# SQL Manual

## 1. DATABASE MANAGEMENT

For more details, see document [Operate-Metadata](../Basic-Concept/Operate-Metadata_apache.md).

### 1.1 Create Database

```sql
create database root.ln;
create database root.sgcc;
```

### 1.2 Show Databases

```sql
SHOW DATABASES;
SHOW DATABASES root.**;
```

### 1.3 Delete Database

```sql
DELETE DATABASE root.ln;
DELETE DATABASE root.sgcc;
// delete all data, all timeseries and all databases;
DELETE DATABASE root.**;
```

### 1.4 Count Databases

```sql
count databases;
count databases root.*;
count databases root.sgcc.*;
count databases root.sgcc;
```

### 1.5 Setting up heterogeneous databases (Advanced operations)

#### Set heterogeneous parameters when creating a Database

```sql
CREATE DATABASE root.db WITH SCHEMA_REPLICATION_FACTOR=1, DATA_REPLICATION_FACTOR=3, SCHEMA_REGION_GROUP_NUM=1, DATA_REGION_GROUP_NUM=2;
```

#### Adjust heterogeneous parameters at run time

```sql
ALTER DATABASE root.db WITH SCHEMA_REGION_GROUP_NUM=1, DATA_REGION_GROUP_NUM=2;
```

#### Show heterogeneous databases

```sql
SHOW DATABASES DETAILS;
```

### 1.6 TTL

#### Set TTL

```sql
set ttl to root.ln 3600000;
set ttl to root.sgcc.** 3600000;
set ttl to root.** 3600000;
```

#### Unset TTL

```sql
unset ttl from root.ln;
unset ttl from root.sgcc.**;
unset ttl from root.**;
```

#### Show TTL

```sql
SHOW ALL TTL;
SHOW TTL ON StorageGroupNames;
SHOW DEVICES;
```

## 2. DEVICE TEMPLATE

For more details, see document [Operate-Metadata](../Basic-Concept/Operate-Metadata_apache.md).

![img](/img/%E6%A8%A1%E6%9D%BF.png)


![img](/img/templateEN.jpg)

### 2.1 Create Device Template

**Example 1:** Create a template containing two non-aligned timeseires

```sql
create device template t1 (temperature FLOAT, status BOOLEAN);
```

**Example 2:** Create a template containing a group of aligned timeseires

```sql
create device template t2 aligned (lat FLOAT, lon FLOAT);
```

The` lat` and `lon` measurements are aligned.

### 2.2 Set Device Template

```sql
set device template t1 to root.sg1.d1;
```

### 2.3 Activate Device Template

```sql
set device template t1 to root.sg1.d1;
set device template t2 to root.sg1.d2;
create timeseries using device template on root.sg1.d1;
create timeseries using device template on root.sg1.d2;
```

### 2.4 Show Device Template

```sql
show device templates;
show nodes in device template t1;
show paths set device template t1;
show paths using device template t1;
```

### 2.5 Deactivate Device Template

```sql
delete timeseries of device template t1 from root.sg1.d1;
deactivate device template t1 from root.sg1.d1;
delete timeseries of device template t1 from root.sg1.*, root.sg2.*;
deactivate device template t1 from root.sg1.*, root.sg2.*;
```

### 2.6 Unset Device Template

```sql
unset device template t1 from root.sg1.d1;
```

### 2.7 Drop Device Template

```sql
drop device template t1;
```

### 2.8 Alter Device Template

```sql
alter device template t1 add (speed FLOAT);
```

## 3. TIMESERIES MANAGEMENT

For more details, see document [Operate-Metadata](../Basic-Concept/Operate-Metadata_apache.md).

### 3.1 Create Timeseries

```sql
create timeseries root.ln.wf01.wt01.status with datatype=BOOLEAN;
create timeseries root.ln.wf01.wt01.temperature with datatype=FLOAT;
create timeseries root.ln.wf02.wt02.hardware with datatype=TEXT;
create timeseries root.ln.wf02.wt02.status with datatype=BOOLEAN;
create timeseries root.sgcc.wf03.wt01.status with datatype=BOOLEAN;
create timeseries root.sgcc.wf03.wt01.temperature with datatype=FLOAT;
```

- From v0.13, you can use a simplified version of the SQL statements to create timeseries:

```sql
create timeseries root.ln.wf01.wt01.status with datatype=BOOLEAN;
create timeseries root.ln.wf01.wt01.temperature with datatype=FLOAT;
create timeseries root.ln.wf02.wt02.hardware with datatype=TEXT;
create timeseries root.ln.wf02.wt02.status with datatype=BOOLEAN;
create timeseries root.sgcc.wf03.wt01.status with datatype=BOOLEAN;
create timeseries root.sgcc.wf03.wt01.temperature with datatype=FLOAT;
```

- Notice that when in the CREATE TIMESERIES statement the encoding method conflicts with the data type, the system gives the corresponding error prompt as shown below:

```sql
create timeseries root.ln.wf02.wt02.status WITH DATATYPE=BOOLEAN, ENCODING=TS_2DIFF;
error: encoding TS_2DIFF does not support BOOLEAN
```

### 3.2 Create Aligned Timeseries

```sql
CREATE ALIGNED TIMESERIES root.ln.wf01.GPS(latitude FLOAT , longitude FLOAT);
```

### 3.3 Delete Timeseries

```sql
delete timeseries root.ln.wf01.wt01.status;
delete timeseries root.ln.wf01.wt01.temperature, root.ln.wf02.wt02.hardware;
delete timeseries root.ln.wf02.*;
drop timeseries root.ln.wf02.*;
```

### 3.4 Show Timeseries

```sql
show timeseries root.**;
show timeseries root.ln.**;
show timeseries root.ln.** limit 10 offset 10;
show timeseries root.ln.** where timeseries contains 'wf01.wt';
show timeseries root.ln.** where dataType=FLOAT;
```

### 3.5 Count Timeseries

```sql
COUNT TIMESERIES root.**;
COUNT TIMESERIES root.ln.**;
COUNT TIMESERIES root.ln.*.*.status;
COUNT TIMESERIES root.ln.wf01.wt01.status;
COUNT TIMESERIES root.** WHERE TIMESERIES contains 'sgcc' ;
COUNT TIMESERIES root.** WHERE DATATYPE = INT64;
COUNT TIMESERIES root.** WHERE TAGS(unit) contains 'c' ;
COUNT TIMESERIES root.** WHERE TAGS(unit) = 'c' ;
COUNT TIMESERIES root.** WHERE TIMESERIES contains 'sgcc' group by level = 1;
COUNT TIMESERIES root.** GROUP BY LEVEL=1;
COUNT TIMESERIES root.ln.** GROUP BY LEVEL=2;
COUNT TIMESERIES root.ln.wf01.* GROUP BY LEVEL=2;
```

### 3.6 Tag and Attribute Management

```sql
create timeseries root.turbine.d1.s1(temprature) with datatype=FLOAT tags(tag1=v1, tag2=v2) attributes(attr1=v1, attr2=v2);
```

* Rename the tag/attribute key

```SQL
ALTER timeseries root.turbine.d1.s1 RENAME tag1 TO newTag1;
```

* Reset the tag/attribute value

```SQL
ALTER timeseries root.turbine.d1.s1 SET newTag1=newV1, attr1=newV1;
```

* Delete the existing tag/attribute

```SQL
ALTER timeseries root.turbine.d1.s1 DROP tag1, tag2;
```

* Add new tags

```SQL
ALTER timeseries root.turbine.d1.s1 ADD TAGS tag3=v3, tag4=v4;
```

* Add new attributes

```SQL
ALTER timeseries root.turbine.d1.s1 ADD ATTRIBUTES attr3=v3, attr4=v4;
```

* Upsert alias, tags and attributes

> add alias or a new key-value if the alias or key doesn't exist, otherwise, update the old one with new value.

```SQL
ALTER timeseries root.turbine.d1.s1 UPSERT ALIAS=newAlias TAGS(tag3=v3, tag4=v4) ATTRIBUTES(attr3=v3, attr4=v4);
```

* Show timeseries using tags. Use TAGS(tagKey) to identify the tags used as filter key

```SQL
SHOW TIMESERIES (<`PathPattern`>)? timeseriesWhereClause;
```

returns all the timeseries information that satisfy the where condition and match the pathPattern. SQL statements are as follows:

```SQL
ALTER timeseries root.ln.wf02.wt02.hardware ADD TAGS unit=c;
ALTER timeseries root.ln.wf02.wt02.status ADD TAGS description=test1;
show timeseries root.ln.** where TAGS(unit)='c';
show timeseries root.ln.** where TAGS(description) contains 'test1';
```

- count timeseries using tags

```SQL
COUNT TIMESERIES (<`PathPattern`>)? timeseriesWhereClause;
COUNT TIMESERIES (<`PathPattern`>)? timeseriesWhereClause GROUP BY LEVEL=<INTEGER>;
```

returns all the number of timeseries that satisfy the where condition and match the pathPattern. SQL statements are as follows:

```SQL
count timeseries;
count timeseries root.** where TAGS(unit)='c';
count timeseries root.** where TAGS(unit)='c' group by level = 2;
```

create aligned timeseries

```SQL
create aligned timeseries root.sg1.d1(s1 INT32 tags(tag1=v1, tag2=v2) attributes(attr1=v1, attr2=v2), s2 DOUBLE tags(tag3=v3, tag4=v4) attributes(attr3=v3, attr4=v4));
```

The execution result is as follows:

```SQL
show timeseries;
```
```shell
+--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+
|    timeseries|alias|     database|dataType|encoding|compression|                     tags|                 attributes|deadband|deadband parameters|
+--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+
|root.sg1.d1.s1| null|     root.sg1|   INT32|     RLE|     SNAPPY|{"tag1":"v1","tag2":"v2"}|{"attr2":"v2","attr1":"v1"}|    null|               null|
|root.sg1.d1.s2| null|     root.sg1|  DOUBLE| GORILLA|     SNAPPY|{"tag4":"v4","tag3":"v3"}|{"attr4":"v4","attr3":"v3"}|    null|               null|
+--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+
```

Support query：

```SQL
show timeseries where TAGS(tag1)='v1';
```
```shell
+--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+
|    timeseries|alias|     database|dataType|encoding|compression|                     tags|                 attributes|deadband|deadband parameters|
+--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+
|root.sg1.d1.s1| null|     root.sg1|   INT32|     RLE|     SNAPPY|{"tag1":"v1","tag2":"v2"}|{"attr2":"v2","attr1":"v1"}|    null|               null|
+--------------+-----+-------------+--------+--------+-----------+-------------------------+---------------------------+--------+-------------------+
```

The above operations are supported for timeseries tag, attribute updates, etc.

## 4. NODE MANAGEMENT

For more details, see document [Operate-Metadata](../Basic-Concept/Operate-Metadata_apache.md).

### 4.1 Show Child Paths

```SQL
SHOW CHILD PATHS pathPattern;
```

### 4.2 Show Child Nodes

```SQL
SHOW CHILD NODES pathPattern;
```

### 4.3 Count Nodes

```SQL
COUNT NODES root.** LEVEL=2;
COUNT NODES root.ln.** LEVEL=2;
COUNT NODES root.ln.wf01.** LEVEL=3;
COUNT NODES root.**.temperature LEVEL=3;
```

### 4.4 Show Devices

```SQL
show devices;
show devices root.ln.**;
show devices root.ln.** where device contains 't';
show devices with database;
show devices root.ln.** with database;
```

### 4.5 Count Devices

```SQL
show devices;
count devices;
count devices root.ln.**;
```

## 5. INSERT & LOAD DATA

### 5.1 Insert Data

For more details, see document [Write-Data](../Basic-Concept/Write-Data_apache).

#### Use of INSERT Statements

-   Insert Single Timeseries

```sql
insert into root.ln.wf02.wt02(timestamp,status) values(1,true);
insert into root.ln.wf02.wt02(timestamp,hardware) values(1, 'v1');
```

-   Insert Multiple Timeseries

```sql
insert into root.ln.wf02.wt02(timestamp, status, hardware) VALUES (2, false, 'v2');
insert into root.ln.wf02.wt02(timestamp, status, hardware) VALUES (3, false, 'v3'),(4, true, 'v4');
```

-   Use the Current System Timestamp as the Timestamp of the Data Point

```SQL
insert into root.ln.wf02.wt02(status, hardware) values (false, 'v2');
```

#### Insert Data Into Aligned Timeseries

```SQL
create aligned timeseries root.sg1.d1(s1 INT32, s2 DOUBLE);
insert into root.sg1.d1(time, s1, s2) aligned values(1, 1, 1);
insert into root.sg1.d1(time, s1, s2) aligned values(2, 2, 2), (3, 3, 3);
select * from root.sg1.d1;
```

### 5.2 Load External TsFile Tool

For more details, see document [Data Import](../Tools-System/Data-Import-Tool_apache).

#### Load with SQL

1.   Load a single tsfile by specifying a file path (absolute path). 

- `load '/Users/Desktop/data/1575028885956-101-0.tsfile'`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' sglevel=1`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' onSuccess=delete`
- `load '/Users/Desktop/data/1575028885956-101-0.tsfile' sglevel=1 onSuccess=delete`


2.   Load a batch of files by specifying a folder path (absolute path). 

- `load '/Users/Desktop/data'`
- `load '/Users/Desktop/data' sglevel=1`
- `load '/Users/Desktop/data' onSuccess=delete`
- `load '/Users/Desktop/data' sglevel=1 onSuccess=delete`

#### Load with Script

```sql
./load-rewrite.bat -f D:\IoTDB\data -h 192.168.0.101 -p 6667 -u root -pw root
```

## 6. DELETE DATA

For more details, see document [Write-Delete-Data](../Basic-Concept/Write-Data_apache).

### 6.1 Delete Single Timeseries

```sql
delete from root.ln.wf02.wt02.status where time<=2017-11-01T16:26:00;
delete from root.ln.wf02.wt02.status where time>=2017-01-01T00:00:00 and time<=2017-11-01T16:26:00;
delete from root.ln.wf02.wt02.status where time < 10;
delete from root.ln.wf02.wt02.status where time <= 10;
delete from root.ln.wf02.wt02.status where time < 20 and time > 10;
delete from root.ln.wf02.wt02.status where time <= 20 and time >= 10;
delete from root.ln.wf02.wt02.status where time > 20;
delete from root.ln.wf02.wt02.status where time >= 20;
delete from root.ln.wf02.wt02.status where time = 20;
delete from root.ln.wf02.wt02.status where time > 4 or time < 0;
Msg: 303: Check metadata error: For delete statement, where clause can only contain atomic;
expressions like : time > XXX, time <= XXX, or two atomic expressions connected by 'AND';
delete from root.ln.wf02.wt02.status;
```

### 6.2 Delete Multiple Timeseries

```sql
delete from root.ln.wf02.wt02 where time <= 2017-11-01T16:26:00;
delete from root.ln.wf02.wt02.* where time <= 2017-11-01T16:26:00;
delete from root.ln.wf03.wt02.status where time < now();
Msg: The statement is executed successfully.
```

### 6.3 Delete Time Partition (experimental)

```sql
DELETE PARTITION root.ln 0,1,2;
```

## 7. QUERY DATA

For more details, see document [Query-Data](../Basic-Concept/Query-Data_apache).

```sql
SELECT [LAST] selectExpr [, selectExpr] ...
    [INTO intoItem [, intoItem] ...]
    FROM prefixPath [, prefixPath] ...
    [WHERE whereCondition]
    [GROUP BY {
        ([startTime, endTime), interval [, slidingStep]) |
        LEVEL = levelNum [, levelNum] ... |
        TAGS(tagKey [, tagKey] ... ) |
        VARIATION(expression[,delta][,ignoreNull=true/false]) |
        CONDITION(expression,[keep>/>=/=/</<=]threshold[,ignoreNull=true/false]) |
        SESSION(timeInterval) |
        COUNT(expression, size[,ignoreNull=true/false])
    }]
    [HAVING havingCondition]
    [ORDER BY sortKey {ASC | DESC}]
    [FILL ({PREVIOUS | LINEAR | constant} (, interval=DURATION_LITERAL)?)]
    [SLIMIT seriesLimit] [SOFFSET seriesOffset]
    [LIMIT rowLimit] [OFFSET rowOffset]
    [ALIGN BY {TIME | DEVICE}]
```

### 7.1 Basic Examples

#### Select a Column of Data Based on a Time Interval

```sql
select temperature from root.ln.wf01.wt01 where time < 2017-11-01T00:08:00.000;
```

#### Select Multiple Columns of Data Based on a Time Interval

```sql
select status, temperature from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000;
```

#### Select Multiple Columns of Data for the Same Device According to Multiple Time Intervals

```sql
select status,temperature from root.ln.wf01.wt01 where (time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000) or (time >= 2017-11-01T16:35:00.000 and time <= 2017-11-01T16:37:00.000);
```

#### Choose Multiple Columns of Data for Different Devices According to Multiple Time Intervals

```sql
select wf01.wt01.status,wf02.wt02.hardware from root.ln where (time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000) or (time >= 2017-11-01T16:35:00.000 and time <= 2017-11-01T16:37:00.000);
```

#### Order By Time Query

```sql
select * from root.ln.** where time > 1 order by time desc limit 10;
```

### 7.2 `SELECT` CLAUSE

#### Use Alias

```sql
select s1 as temperature, s2 as speed from root.ln.wf01.wt01;
```

#### Nested Expressions

##### Nested Expressions with Time Series Query

```sql
select a,
       b,
       ((a + 1) * 2 - 1) % 2 + 1.5,
       sin(a + sin(a + sin(b))),
       -(a + b) * (sin(a + b) * sin(a + b) + cos(a + b) * cos(a + b)) + 1
from root.sg1;

select (a + b) * 2 + sin(a) from root.sg;

select (a + *) / 2  from root.sg1;

select (a + b) * 3 from root.sg, root.ln;
```

##### Nested Expressions query with aggregations

```sql
select avg(temperature),
       sin(avg(temperature)),
       avg(temperature) + 1,
       -sum(hardware),
       avg(temperature) + sum(hardware)
from root.ln.wf01.wt01;

select avg(*), 
	   (avg(*) + 1) * 3 / 2 -1 
from root.sg1;

select avg(temperature),
       sin(avg(temperature)),
       avg(temperature) + 1,
       -sum(hardware),
       avg(temperature) + sum(hardware) as custom_sum
from root.ln.wf01.wt01
GROUP BY([10, 90), 10ms);
```

#### Last Query

```sql
select last status from root.ln.wf01.wt01;
select last status, temperature from root.ln.wf01.wt01 where time >= 2017-11-07T23:50:00;
select last * from root.ln.wf01.wt01 order by timeseries desc;
select last * from root.ln.wf01.wt01 order by dataType desc;
```

### 7.3 `WHERE` CLAUSE

#### Time Filter

```sql
select s1 from root.sg1.d1 where time > 2022-01-01T00:05:00.000;
select s1 from root.sg1.d1 where time = 2022-01-01T00:05:00.000;
select s1 from root.sg1.d1 where time >= 2022-01-01T00:05:00.000 and time < 2017-11-01T00:12:00.000;
```

#### Value Filter

```sql
select temperature from root.sg1.d1 where temperature > 36.5;
select status from root.sg1.d1 where status = true;
select temperature from root.sg1.d1 where temperature between 36.5 and 40;
select temperature from root.sg1.d1 where temperature not between 36.5 and 40;
select code from root.sg1.d1 where code in ('200', '300', '400', '500');
select code from root.sg1.d1 where code not in ('200', '300', '400', '500');
select code from root.sg1.d1 where temperature is null;
select code from root.sg1.d1 where temperature is not null;
```

#### Fuzzy Query

-   Fuzzy matching using `Like`

```sql
select * from root.sg.d1 where value like '%cc%';
select * from root.sg.device where value like '_b_';
```

-   Fuzzy matching using `Regexp`

```sql
select * from root.sg.d1 where value regexp '^[A-Za-z]+$';
select * from root.sg.d1 where value regexp '^[a-z]+$' and time > 100;
```

### 7.4 `GROUP BY` CLAUSE

-   Aggregate By Time without Specifying the Sliding Step Length

```sql
select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d);
```

-   Aggregate By Time Specifying the Sliding Step Length

```sql
select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01 00:00:00, 2017-11-07 23:00:00), 3h, 1d);
```

-   Aggregate by Natural Month

```sql
select count(status) from root.ln.wf01.wt01 group by([2017-11-01T00:00:00, 2019-11-07T23:00:00), 1mo, 2mo);
select count(status) from root.ln.wf01.wt01 group by([2017-10-31T00:00:00, 2019-11-07T23:00:00), 1mo, 2mo);                                                    
```

-   Left Open And Right Close Range

```sql
select count(status) from root.ln.wf01.wt01 group by ((2017-11-01T00:00:00, 2017-11-07T23:00:00],1d);
```

-   Aggregation By Variation

```sql
select __endTime, avg(s1), count(s2), sum(s3) from root.sg.d group by variation(s6);
select __endTime, avg(s1), count(s2), sum(s3) from root.sg.d group by variation(s6, ignoreNull=false);
select __endTime, avg(s1), count(s2), sum(s3) from root.sg.d group by variation(s6, 4);
select __endTime, avg(s1), count(s2), sum(s3) from root.sg.d group by variation(s6+s5, 10);
```

-   Aggregation By Condition

```sql
select max_time(charging_status),count(vehicle_status),last_value(soc) from root.** group by condition(charging_status=1,KEEP>=2,ignoringNull=true);
select max_time(charging_status),count(vehicle_status),last_value(soc) from root.** group by condition(charging_status=1,KEEP>=2,ignoringNull=false);
```

-   Aggregation By Session

```sql
select __endTime,count(*) from root.** group by session(1d);
select __endTime,sum(hardware) from root.ln.wf02.wt01 group by session(50s) having sum(hardware)>0 align by device;
```

-   Aggregation By Count

```sql
select count(charging_stauts), first_value(soc) from root.sg group by count(charging_status,5);
select count(charging_stauts), first_value(soc) from root.sg group by count(charging_status,5,ignoreNull=false);
```

-   Aggregation By Level

```sql
select count(status) from root.** group by level = 1;
select count(status) from root.** group by level = 3;
select count(status) from root.** group by level = 1, 3;
select max_value(temperature) from root.** group by level = 0;
select count(*) from root.ln.** group by level = 2;
```

-   Aggregate By Time with Level Clause

```sql
select count(status) from root.ln.wf01.wt01 group by ((2017-11-01T00:00:00, 2017-11-07T23:00:00],1d), level=1;
select count(status) from root.ln.wf01.wt01 group by ([2017-11-01 00:00:00, 2017-11-07 23:00:00), 3h, 1d), level=1;
```

-   Aggregation query by one single tag

```sql
SELECT AVG(temperature) FROM root.factory1.** GROUP BY TAGS(city);
```

-   Aggregation query by multiple tags

```sql
SELECT avg(temperature) FROM root.factory1.** GROUP BY TAGS(city, workshop);
```

-   Downsampling Aggregation by tags based on Time Window

```sql
SELECT avg(temperature) FROM root.factory1.** GROUP BY ([1000, 10000), 5s), TAGS(city, workshop);
```

### 7.5 `HAVING` CLAUSE

Correct:

```sql
select count(s1) from root.** group by ([1,11),2ms), level=1 having count(s2) > 1;
select count(s1), count(s2) from root.** group by ([1,11),2ms) having count(s2) > 1 align by device;
```

Incorrect: 

```sql
select count(s1) from root.** group by ([1,3),1ms) having sum(s1) > s1;
select count(s1) from root.** group by ([1,3),1ms) having s1 > 1;
select count(s1) from root.** group by ([1,3),1ms), level=1 having sum(d1.s1) > 1;
select count(d1.s1) from root.** group by ([1,3),1ms), level=1 having sum(s1) > 1;
```

### 7.6 `FILL` CLAUSE

#### `PREVIOUS` Fill

```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(previous);
```

#### `PREVIOUS` FILL and specify the fill timeout threshold
```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(previous, 2m);
```

#### `LINEAR` Fill

```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(linear);
```

#### Constant Fill

```sql
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(2.0);
select temperature, status from root.sgcc.wf03.wt01 where time >= 2017-11-01T16:37:00.000 and time <= 2017-11-01T16:40:00.000 fill(true);
```

### 7.7 `LIMIT` and `SLIMIT` CLAUSES (PAGINATION)

#### Row Control over Query Results

```sql
select status, temperature from root.ln.wf01.wt01 limit 10;
select status, temperature from root.ln.wf01.wt01 limit 5 offset 3;
select status,temperature from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time< 2017-11-01T00:12:00.000 limit 2 offset 3;
select count(status), max_value(temperature) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d) limit 5 offset 3;
```

#### Column Control over Query Results

```sql
select * from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000 slimit 1;
select * from root.ln.wf01.wt01 where time > 2017-11-01T00:05:00.000 and time < 2017-11-01T00:12:00.000 slimit 1 soffset 1;
select max_value(*) from root.ln.wf01.wt01 group by ([2017-11-01T00:00:00, 2017-11-07T23:00:00),1d) slimit 1 soffset 1;
```

#### Row and Column Control over Query Results

```sql
select * from root.ln.wf01.wt01 limit 10 offset 100 slimit 2 soffset 0;
```

### 7.8 `ORDER BY` CLAUSE

#### Order by in ALIGN BY TIME mode

```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 order by time desc;
```

#### Order by in ALIGN BY DEVICE mode

```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 order by device desc,time asc align by device;
select * from root.ln.** where time <= 2017-11-01T00:01:00 order by time asc,device desc align by device;
select * from root.ln.** where time <= 2017-11-01T00:01:00 align by device;
select count(*) from root.ln.** group by ((2017-11-01T00:00:00.000+08:00,2017-11-01T00:03:00.000+08:00],1m) order by device asc,time asc align by device;
```

#### Order by arbitrary expressions

```sql
select score from root.** order by score desc align by device;
select score,total from root.one order by base+score+bonus desc;
select score,total from root.one order by total desc;
select base, score, bonus, total from root.** order by total desc NULLS Last,
                                  score desc NULLS Last,
                                  bonus desc NULLS Last,
                                  time desc align by device;
select min_value(total) from root.** order by min_value(total) asc align by device;
select min_value(total),max_value(base) from root.** order by max_value(total) desc align by device;
select score from root.** order by device asc, score desc, time asc align by device;
```

### 7.9 `ALIGN BY` CLAUSE

#### Align by Device

```sql
select * from root.ln.** where time <= 2017-11-01T00:01:00 align by device;
```

### 7.10 `INTO` CLAUSE (QUERY WRITE-BACK)

```sql
select s1, s2 into root.sg_copy.d1(t1), root.sg_copy.d2(t1, t2), root.sg_copy.d1(t2) from root.sg.d1, root.sg.d2;
select count(s1 + s2), last_value(s2) into root.agg.count(s1_add_s2), root.agg.last_value(s2) from root.sg.d1 group by ([0, 100), 10ms);
select s1, s2 into root.sg_copy.d1(t1, t2), root.sg_copy.d2(t1, t2) from root.sg.d1, root.sg.d2 align by device;
select s1 + s2 into root.expr.add(d1s1_d1s2), root.expr.add(d2s1_d2s2) from root.sg.d1, root.sg.d2 align by device;
```

-   Using variable placeholders:

```sql
select s1, s2
into root.sg_copy.d1(::), root.sg_copy.d2(s1), root.sg_copy.d1(${3}), root.sg_copy.d2(::)
from root.sg.d1, root.sg.d2;

select d1.s1, d1.s2, d2.s3, d3.s4
into ::(s1_1, s2_2), root.sg.d2_2(s3_3), root.${2}_copy.::(s4)
from root.sg;

select * into root.sg_bk.::(::) from root.sg.**;

select s1, s2, s3, s4
into root.backup_sg.d1(s1, s2, s3, s4), root.backup_sg.d2(::), root.sg.d3(backup_${4})
from root.sg.d1, root.sg.d2, root.sg.d3
align by device;

select avg(s1), sum(s2) + sum(s3), count(s4)
into root.agg_${2}.::(avg_s1, sum_s2_add_s3, count_s4)
from root.**
align by device;

select * into ::(backup_${4}) from root.sg.** align by device;

select s1, s2 into root.sg_copy.d1(t1, t2), aligned root.sg_copy.d2(t1, t2) from root.sg.d1, root.sg.d2 align by device;
```

## 8. Maintennance
Generate the corresponding query plan:
```sql
explain select s1,s2 from root.sg.d1;
```
Execute the corresponding SQL, analyze the execution and output:
```sql
explain analyze select s1,s2 from root.sg.d1 order by s1;
``` 
## 9. OPERATOR

For more details, see document [Operator-and-Expression](./Operator-and-Expression.md).

### 9.1 Arithmetic Operators

For details and examples, see the document [Arithmetic Operators and Functions](./Operator-and-Expression.md#_1-1-arithmetic-operators).

```sql
select s1, - s1, s2, + s2, s1 + s2, s1 - s2, s1 * s2, s1 / s2, s1 % s2 from root.sg.d1;
```

### 9.2 Comparison Operators

For details and examples, see the document [Comparison Operators and Functions](./Operator-and-Expression.md#_1-2-comparison-operators).

```sql
# Basic comparison operators
select a, b, a > 10, a <= b, !(a <= b), a > 10 && a > b from root.test;

# `BETWEEN ... AND ...` operator
select temperature from root.sg1.d1 where temperature between 36.5 and 40;
select temperature from root.sg1.d1 where temperature not between 36.5 and 40;

# Fuzzy matching operator: Use `Like` for fuzzy matching
select * from root.sg.d1 where value like '%cc%';
select * from root.sg.device where value like '_b_';

# Fuzzy matching operator: Use `Regexp` for fuzzy matching
select * from root.sg.d1 where value regexp '^[A-Za-z]+$';
select * from root.sg.d1 where value regexp '^[a-z]+$' and time > 100;
select b, b like '1%', b regexp '[0-2]' from root.test;

# `IS NULL` operator
select code from root.sg1.d1 where temperature is null;
select code from root.sg1.d1 where temperature is not null;

# `IN` operator
select code from root.sg1.d1 where code in ('200', '300', '400', '500');
select code from root.sg1.d1 where code not in ('200', '300', '400', '500');
select a, a in (1, 2) from root.test;
```

### 9.3 Logical Operators

For details and examples, see the document [Logical Operators](./Operator-and-Expression.md#_1-3-logical-operators).

```sql
select a, b, a > 10, a <= b, !(a <= b), a > 10 && a > b from root.test;
```

## 10. BUILT-IN FUNCTIONS

For more details, see document [Operator-and-Expression](./Operator-and-Expression.md#_2-built-in-functions).

### 10.1 Aggregate Functions

For details and examples, see the document [Aggregate Functions](./Operator-and-Expression.md#_2-1-aggregate-functions).

```sql
select count(status) from root.ln.wf01.wt01;

select count_if(s1=0 & s2=0, 3), count_if(s1=1 & s2=0, 3) from root.db.d1;
select count_if(s1=0 & s2=0, 3, 'ignoreNull'='false'), count_if(s1=1 & s2=0, 3, 'ignoreNull'='false') from root.db.d1;

select time_duration(s1) from root.db.d1;
```

### 10.2 Arithmetic Functions

For details and examples, see the document [Arithmetic Operators and Functions](./Operator-and-Expression.md#_2-2-arithmetic-functions).

```sql
select s1, sin(s1), cos(s1), tan(s1) from root.sg1.d1 limit 5 offset 1000;
select s4,round(s4),round(s4,2),round(s4,-1) from root.sg1.d1;
```

### 10.3 Comparison Functions

For details and examples, see the document [Comparison Operators and Functions](./Operator-and-Expression.md#_2-3-comparison-functions).

```sql
select ts, on_off(ts, 'threshold'='2') from root.test;
select ts, in_range(ts, 'lower'='2', 'upper'='3.1') from root.test;
```

### 10.4 String Processing Functions

For details and examples, see the document [String Processing](./Operator-and-Expression.md#_2-4-string-processing-functions).

```sql
select s1, string_contains(s1, 's'='warn') from root.sg1.d4;
select s1, string_matches(s1, 'regex'='[^\\s]+37229') from root.sg1.d4;
select s1, length(s1) from root.sg1.d1;
select s1, locate(s1, "target"="1") from root.sg1.d1;
select s1, locate(s1, "target"="1", "reverse"="true") from root.sg1.d1;
select s1, startswith(s1, "target"="1") from root.sg1.d1;
select s1, endswith(s1, "target"="1") from root.sg1.d1;
select s1, s2, concat(s1, s2, "target1"="IoT", "target2"="DB") from root.sg1.d1;
select s1, s2, concat(s1, s2, "target1"="IoT", "target2"="DB", "series_behind"="true") from root.sg1.d1;
select s1, substring(s1 from 1 for 2) from root.sg1.d1;
select s1, replace(s1, 'es', 'tt') from root.sg1.d1;
select s1, upper(s1) from root.sg1.d1;
select s1, lower(s1) from root.sg1.d1;
select s3, trim(s3) from root.sg1.d1;
select s1, s2, strcmp(s1, s2) from root.sg1.d1;
select strreplace(s1, "target"=",", "replace"="/", "limit"="2") from root.test.d1;
select strreplace(s1, "target"=",", "replace"="/", "limit"="1", "offset"="1", "reverse"="true") from root.test.d1;
select regexmatch(s1, "regex"="\d+\.\d+\.\d+\.\d+", "group"="0") from root.test.d1;
select regexreplace(s1, "regex"="192\.168\.0\.(\d+)", "replace"="cluster-$1", "limit"="1") from root.test.d1;
select regexsplit(s1, "regex"=",", "index"="-1") from root.test.d1;
select regexsplit(s1, "regex"=",", "index"="3") from root.test.d1;
```

### 10.5 Data Type Conversion Function

For details and examples, see the document [Data Type Conversion Function](./Operator-and-Expression.md#_2-5-data-type-conversion-function).

```sql
SELECT cast(s1 as INT32) from root.sg;
```

### 10.6 Constant Timeseries Generating Functions

For details and examples, see the document [Constant Timeseries Generating Functions](./Operator-and-Expression.md#_2-6-constant-timeseries-generating-functions).

```sql
select s1, s2, const(s1, 'value'='1024', 'type'='INT64'), pi(s2), e(s1, s2) from root.sg1.d1; 
```

### 10.7 Selector Functions

For details and examples, see the document [Selector Functions](./Operator-and-Expression.md#_2-7-selector-functions).

```sql
select s1, top_k(s1, 'k'='2'), bottom_k(s1, 'k'='2') from root.sg1.d2 where time > 2020-12-10T20:36:15.530+08:00;
```

### 10.8 Continuous Interval Functions

For details and examples, see the document [Continuous Interval Functions](./Operator-and-Expression.md#_2-8-continuous-interval-functions).

```sql
select s1, zero_count(s1), non_zero_count(s2), zero_duration(s3), non_zero_duration(s4) from root.sg.d2;
```

### 10.9 Variation Trend Calculation Functions

For details and examples, see the document [Variation Trend Calculation Functions](./Operator-and-Expression.md#_2-9-variation-trend-calculation-functions).

```sql
select s1, time_difference(s1), difference(s1), non_negative_difference(s1), derivative(s1), non_negative_derivative(s1) from root.sg1.d1 limit 5 offset 1000; 

SELECT DIFF(s1), DIFF(s2) from root.test;
SELECT DIFF(s1, 'ignoreNull'='false'), DIFF(s2, 'ignoreNull'='false') from root.test;
```

### 10.10 Sample Functions

For details and examples, see the document [Sample Functions](./Operator-and-Expression.md#_2-10-sample-functions).

```sql
select equal_size_bucket_random_sample(temperature,'proportion'='0.1') as random_sample from root.ln.wf01.wt01;
select equal_size_bucket_agg_sample(temperature, 'type'='avg','proportion'='0.1') as agg_avg, equal_size_bucket_agg_sample(temperature, 'type'='max','proportion'='0.1') as agg_max, equal_size_bucket_agg_sample(temperature,'type'='min','proportion'='0.1') as agg_min, equal_size_bucket_agg_sample(temperature, 'type'='sum','proportion'='0.1') as agg_sum, equal_size_bucket_agg_sample(temperature, 'type'='extreme','proportion'='0.1') as agg_extreme, equal_size_bucket_agg_sample(temperature, 'type'='variance','proportion'='0.1') as agg_variance from root.ln.wf01.wt01;
select equal_size_bucket_m4_sample(temperature, 'proportion'='0.1') as M4_sample from root.ln.wf01.wt01;
select equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='avg', 'number'='2') as outlier_avg_sample, equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='stendis', 'number'='2') as outlier_stendis_sample, equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='cos', 'number'='2') as outlier_cos_sample, equal_size_bucket_outlier_sample(temperature, 'proportion'='0.1', 'type'='prenextdis', 'number'='2') as outlier_prenextdis_sample from root.ln.wf01.wt01;

select M4(s1,'timeInterval'='25','displayWindowBegin'='0','displayWindowEnd'='100') from root.vehicle.d1;
select M4(s1,'windowSize'='10') from root.vehicle.d1;
```

### 10.11 Change Points Function

For details and examples, see the document [Time-Series](./Operator-and-Expression.md#_2-11-change-points-function).

```sql
select change_points(s1), change_points(s2), change_points(s3), change_points(s4), change_points(s5), change_points(s6) from root.testChangePoints.d1;
```

## 11. DATA QUALITY FUNCTION LIBRARY

For more details, see document [Operator-and-Expression](../SQL-Manual/UDF-Libraries.md).

### 11.1 Data Quality

For details and examples, see the document [Data-Quality](../SQL-Manual/UDF-Libraries.md#data-quality).

```sql
# Completeness
select completeness(s1) from root.test.d1 where time <= 2020-01-01 00:00:30;
select completeness(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00;

# Consistency
select consistency(s1) from root.test.d1 where time <= 2020-01-01 00:00:30;
select consistency(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00;

# Timeliness
select timeliness(s1) from root.test.d1 where time <= 2020-01-01 00:00:30;
select timeliness(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00;

# Validity
select Validity(s1) from root.test.d1 where time <= 2020-01-01 00:00:30;
select Validity(s1,"window"="15") from root.test.d1 where time <= 2020-01-01 00:01:00;

# Accuracy
select Accuracy(t1,t2,t3,m1,m2,m3) from root.test;
```

### 11.2 Data Profiling

For details and examples, see the document [Data-Profiling](../SQL-Manual/UDF-Libraries.md#data-profiling).

```sql
# ACF
select acf(s1) from root.test.d1 where time <= 2020-01-01 00:00:05;

# Distinct
select distinct(s2) from root.test.d2;

# Histogram
select histogram(s1,"min"="1","max"="20","count"="10") from root.test.d1;

# Integral
select integral(s1) from root.test.d1 where time <= 2020-01-01 00:00:10;
select integral(s1, "unit"="1m") from root.test.d1 where time <= 2020-01-01 00:00:10;

# IntegralAvg
select integralavg(s1) from root.test.d1 where time <= 2020-01-01 00:00:10;

# Mad
select mad(s0) from root.test;
select mad(s0, "error"="0.01") from root.test;

# Median
select median(s0, "error"="0.01") from root.test;

# MinMax
select minmax(s1) from root.test;

# Mode
select mode(s2) from root.test.d2;

# MvAvg
select mvavg(s1, "window"="3") from root.test;

# PACF
select pacf(s1, "lag"="5") from root.test;

# Percentile
select percentile(s0, "rank"="0.2", "error"="0.01") from root.test;

# Quantile
select quantile(s0, "rank"="0.2", "K"="800") from root.test;

# Period
select period(s1) from root.test.d3;

# QLB
select QLB(s1) from root.test.d1;

# Resample
select resample(s1,'every'='5m','interp'='linear') from root.test.d1;
select resample(s1,'every'='30m','aggr'='first') from root.test.d1;
select resample(s1,'every'='30m','start'='2021-03-06 15:00:00') from root.test.d1;

# Sample
select sample(s1,'method'='reservoir','k'='5') from root.test.d1;
select sample(s1,'method'='isometric','k'='5') from root.test.d1;

# Segment
select segment(s1, "error"="0.1") from root.test;

# Skew
select skew(s1) from root.test.d1;

# Spline
select spline(s1, "points"="151") from root.test;

# Spread
select spread(s1) from root.test.d1 where time <= 2020-01-01 00:00:30;

# Stddev
select stddev(s1) from root.test.d1;

# ZScore
select zscore(s1) from root.test;
```

### 11.3 Anomaly Detection

For details and examples, see the document [Anomaly-Detection](../SQL-Manual/UDF-Libraries.md#anomaly-detection).

```sql
# IQR
select iqr(s1) from root.test;

# KSigma
select ksigma(s1,"k"="1.0") from root.test.d1 where time <= 2020-01-01 00:00:30;

# LOF
select lof(s1,s2) from root.test.d1 where time<1000;
select lof(s1, "method"="series") from root.test.d1 where time<1000;

# MissDetect
select missdetect(s2,'minlen'='10') from root.test.d2;

# Range
select range(s1,"lower_bound"="101.0","upper_bound"="125.0") from root.test.d1 where time <= 2020-01-01 00:00:30;

# TwoSidedFilter
select TwoSidedFilter(s0, 'len'='5', 'threshold'='0.3') from root.test;

# Outlier
select outlier(s1,"r"="5.0","k"="4","w"="10","s"="5") from root.test;

# MasterTrain
select MasterTrain(lo,la,m_lo,m_la,'p'='3','eta'='1.0') from root.test;

# MasterDetect
select MasterDetect(lo,la,m_lo,m_la,model,'output_type'='repair','p'='3','k'='3','eta'='1.0') from root.test;
select MasterDetect(lo,la,m_lo,m_la,model,'output_type'='anomaly','p'='3','k'='3','eta'='1.0') from root.test;
```

### 11.4 Frequency Domain

For details and examples, see the document [Frequency-Domain](../SQL-Manual/UDF-Libraries.md#frequency-domain-analysis).

```sql
# Conv
select conv(s1,s2) from root.test.d2;

# Deconv
select deconv(s3,s2) from root.test.d2;
select deconv(s3,s2,'result'='remainder') from root.test.d2;

# DWT
select dwt(s1,"method"="haar") from root.test.d1;

# FFT
select fft(s1) from root.test.d1;
select fft(s1, 'result'='real', 'compress'='0.99'), fft(s1, 'result'='imag','compress'='0.99') from root.test.d1;

# HighPass
select highpass(s1,'wpass'='0.45') from root.test.d1;

# IFFT
select ifft(re, im, 'interval'='1m', 'start'='2021-01-01 00:00:00') from root.test.d1;

# LowPass
select lowpass(s1,'wpass'='0.45') from root.test.d1;

# Envelope
select envelope(s1) from root.test.d1;
```

### 11.5 Data Matching

For details and examples, see the document [Data-Matching](../SQL-Manual/UDF-Libraries.md#data-matching).

```sql
# Cov
select cov(s1,s2) from root.test.d2;

# DTW
select dtw(s1,s2) from root.test.d2;

# Pearson
select pearson(s1,s2) from root.test.d2;

# PtnSym
select ptnsym(s4, 'window'='5', 'threshold'='0') from root.test.d1;

# XCorr
select xcorr(s1, s2) from root.test.d1 where time <= 2020-01-01 00:00:05;
```

### 11.6 Data Repairing

For details and examples, see the document [Data-Repairing](../SQL-Manual/UDF-Libraries.md#data-repairing).

```sql
# TimestampRepair
select timestamprepair(s1,'interval'='10000') from root.test.d2;
select timestamprepair(s1) from root.test.d2;

# ValueFill
select valuefill(s1) from root.test.d2;
select valuefill(s1,"method"="previous") from root.test.d2;

# ValueRepair
select valuerepair(s1) from root.test.d2;
select valuerepair(s1,'method'='LsGreedy') from root.test.d2;

# MasterRepair
select MasterRepair(t1,t2,t3,m1,m2,m3) from root.test;

# SeasonalRepair
select seasonalrepair(s1,'period'=3,'k'=2) from root.test.d2;
select seasonalrepair(s1,'method'='improved','period'=3) from root.test.d2;
```

### 11.7 Series Discovery

For details and examples, see the document [Series-Discovery](../SQL-Manual/UDF-Libraries.md#series-discovery).

```sql
# ConsecutiveSequences
select consecutivesequences(s1,s2,'gap'='5m') from root.test.d1;
select consecutivesequences(s1,s2) from root.test.d1;

# ConsecutiveWindows
select consecutivewindows(s1,s2,'length'='10m') from root.test.d1;
```

### 11.8 Machine Learning

For details and examples, see the document [Machine-Learning](../SQL-Manual/UDF-Libraries.md#machine-learning).

```sql
# AR
select ar(s0,"p"="2") from root.test.d0;

# Representation
select representation(s0,"tb"="3","vb"="2") from root.test.d0;

# RM
select rm(s0, s1,"tb"="3","vb"="2") from root.test.d0;
```

## 12. CONDITIONAL EXPRESSION

For details and examples, see the document [Conditional Expressions](../SQL-Manual/UDF-Libraries.md#conditional-expressions).

```sql
select T, P, case
when 1000<T and T<1050 and 1000000<P and P<1100000 then "good!"
when T<=1000 or T>=1050 then "bad temperature"
when P<=1000000 or P>=1100000 then "bad pressure"
end as `result`
from root.test1;

select str, case
when str like "%cc%" then "has cc"
when str like "%dd%" then "has dd"
else "no cc and dd" end as `result`
from root.test2;

select
count(case when x<=1 then 1 end) as `(-∞,1]`,
count(case when 1<x and x<=3 then 1 end) as `(1,3]`,
count(case when 3<x and x<=7 then 1 end) as `(3,7]`,
count(case when 7<x then 1 end) as `(7,+∞)`
from root.test3;

select x, case x when 1 then "one" when 2 then "two" else "other" end from root.test4;

select x, case x when 1 then true when 2 then false end as `result` from root.test4;

select x, case x
when 1 then 1
when 2 then 222222222222222
when 3 then 3.3
when 4 then 4.4444444444444
end as `result`
from root.test4;
```

## 13. TRIGGER

For more details, see document [TRIGGER](../User-Manual/Trigger.md).

### 13.1 Create Trigger

```sql
// Create Trigger
createTrigger
    : CREATE triggerType TRIGGER triggerName=identifier triggerEventClause ON pathPattern AS className=STRING_LITERAL uriClause? triggerAttributeClause?
    ;

triggerType
    : STATELESS | STATEFUL
    ;

triggerEventClause
    : (BEFORE | AFTER) INSERT
    ;
        
uriClause
    : USING URI uri
    ;

uri
    : STRING_LITERAL
    ;
    
triggerAttributeClause
    : WITH LR_BRACKET triggerAttribute (COMMA triggerAttribute)* RR_BRACKET
    ;

triggerAttribute
    : key=attributeKey operator_eq value=attributeValue
    ;
```

### 13.2 Drop Trigger

```sql
// Drop Trigger
dropTrigger
  : DROP TRIGGER triggerName=identifier
;
```

### 13.3 Show Trigger

```sql
SHOW TRIGGERS
```

## 14. CONTINUOUS QUERY (CQ)

For more details, see document [CONTINUOUS QUERY](../User-Manual/Database-Programming.md).

```sql
CREATE (CONTINUOUS QUERY | CQ) <cq_id> 
[RESAMPLE 
  [EVERY <every_interval>] 
  [BOUNDARY <execution_boundary_time>]
  [RANGE <start_time_offset>[, end_time_offset]] 
]
[TIMEOUT POLICY BLOCKED|DISCARD]
BEGIN
  SELECT CLAUSE
    INTO CLAUSE
    FROM CLAUSE
    [WHERE CLAUSE]
    [GROUP BY(<group_by_interval>[, <sliding_step>]) [, level = <level>]]
    [HAVING CLAUSE]
    [FILL ({PREVIOUS | LINEAR | constant} (, interval=DURATION_LITERAL)?)]
    [LIMIT rowLimit OFFSET rowOffset]
    [ALIGN BY DEVICE]
END
```

### 14.1 Configuring execution intervals

```sql
CREATE CONTINUOUS QUERY cq1
RESAMPLE EVERY 20s
BEGIN
SELECT max_value(temperature)
  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)
  FROM root.ln.*.*
  GROUP BY(10s)
END;
```

### 14.2 Configuring time range for resampling

```sql
CREATE CONTINUOUS QUERY cq2
RESAMPLE RANGE 40s
BEGIN
  SELECT max_value(temperature)
  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)
  FROM root.ln.*.*
  GROUP BY(10s)
END;
```

### 14.3 Configuring execution intervals and CQ time ranges

```sql
CREATE CONTINUOUS QUERY cq3
RESAMPLE EVERY 20s RANGE 40s
BEGIN
  SELECT max_value(temperature)
  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)
  FROM root.ln.*.*
  GROUP BY(10s)
  FILL(100.0)
END;
```

### 14.4 Configuring end_time_offset for CQ time range

```sql
CREATE CONTINUOUS QUERY cq4
RESAMPLE EVERY 20s RANGE 40s, 20s
BEGIN
  SELECT max_value(temperature)
  INTO root.ln.wf02.wt02(temperature_max), root.ln.wf02.wt01(temperature_max), root.ln.wf01.wt02(temperature_max), root.ln.wf01.wt01(temperature_max)
  FROM root.ln.*.*
  GROUP BY(10s)
  FILL(100.0)
END;
```

### 14.5 CQ without group by clause

```sql
CREATE CONTINUOUS QUERY cq5
RESAMPLE EVERY 20s
BEGIN
  SELECT temperature + 1
  INTO root.precalculated_sg.::(temperature)
  FROM root.ln.*.*
  align by device
END;
```

### 14.6 CQ Management

#### Listing continuous queries

```sql
SHOW (CONTINUOUS QUERIES | CQS) ;
```

#### Dropping continuous queries

```sql
DROP (CONTINUOUS QUERY | CQ) <cq_id>;
```

#### Altering continuous queries

CQs can't be altered once they're created. To change a CQ, you must `DROP` and re`CREATE` it with the updated settings.

## 15. USER-DEFINED FUNCTION (UDF)

For more details, see document [UDF Libraries](../SQL-Manual/UDF-Libraries.md).

### 15.1 UDF Registration

```sql
CREATE FUNCTION <UDF-NAME> AS <UDF-CLASS-FULL-PATHNAME> (USING URI URI-STRING)?
```

### 15.2 UDF Deregistration

```sql
DROP FUNCTION <UDF-NAME>
```

### 15.3 UDF Queries

```sql
SELECT example(*) from root.sg.d1;
SELECT example(s1, *) from root.sg.d1;
SELECT example(*, *) from root.sg.d1;

SELECT example(s1, 'key1'='value1', 'key2'='value2'), example(*, 'key3'='value3') FROM root.sg.d1;
SELECT example(s1, s2, 'key1'='value1', 'key2'='value2') FROM root.sg.d1;

SELECT s1, s2, example(s1, s2) FROM root.sg.d1;
SELECT *, example(*) FROM root.sg.d1 DISABLE ALIGN;
SELECT s1 * example(* / s1 + s2) FROM root.sg.d1;
SELECT s1, s2, s1 + example(s1, s2), s1 - example(s1 + example(s1, s2) / s2) FROM root.sg.d1;
```

### 15.4 Show All Registered UDFs

```sql
SHOW FUNCTIONS
```

## 16. ADMINISTRATION MANAGEMENT

For more details, see document [Authority Management](../User-Manual/Authority-Management_apache.md).

### 16.1 SQL Statements

- Create user (Requires MANAGE_USER permission)

```SQL
CREATE USER <userName> <password>;
eg: CREATE USER user1 'passwd';
```

- Delete user (Requires MANAGE_USER permission)

```sql
DROP USER <userName>;
eg: DROP USER user1;
```

- Create role (Requires MANAGE_ROLE permission)

```sql
CREATE ROLE <roleName>;
eg: CREATE ROLE role1;
```

- Delete role (Requires MANAGE_ROLE permission)

```sql
DROP ROLE <roleName>;
eg: DROP ROLE role1;
```

- Grant role to user (Requires MANAGE_ROLE permission)

```sql
GRANT ROLE <ROLENAME> TO <USERNAME>;
eg: GRANT ROLE admin TO user1;
```

- Revoke role from user(Requires MANAGE_ROLE permission)

```sql
REVOKE ROLE <ROLENAME> FROM <USER>;
eg: REVOKE ROLE admin FROM user1;
```

- List all user (Requires MANAGE_USER permission)

```sql
LIST USER
```

- List all role (Requires MANAGE_ROLE permission)

```sql
LIST ROLE
```

- List all users granted specific role.（Requires MANAGE_USER permission)

```sql
LIST USER OF ROLE <roleName>;
eg: LIST USER OF ROLE roleuser;
```

- List all role granted to specific user.

```sql
LIST ROLE OF USER <username>;
eg: LIST ROLE OF USER tempuser;
```

- List all privileges of user

```sql
LIST PRIVILEGES OF USER <username>;
eg: LIST PRIVILEGES OF USER tempuser;
```

- List all privileges of role

```sql
LIST PRIVILEGES OF ROLE <roleName>;
eg: LIST PRIVILEGES OF ROLE actor;
```

- Modify password

```sql
ALTER USER <username> SET PASSWORD <password>;
eg: ALTER USER tempuser SET PASSWORD 'newpwd';
```

### 16.2 Authorization and Deauthorization


```sql
GRANT <PRIVILEGES> ON <PATHS> TO ROLE/USER <NAME> [WITH GRANT OPTION];
eg: GRANT READ ON root.** TO ROLE role1;
eg: GRANT READ_DATA, WRITE_DATA ON root.t1.** TO USER user1;
eg: GRANT READ_DATA, WRITE_DATA ON root.t1.**,root.t2.** TO USER user1;
eg: GRANT MANAGE_ROLE ON root.** TO USER user1 WITH GRANT OPTION;
eg: GRANT ALL ON root.** TO USER user1 WITH GRANT OPTION;
```

```sql
REVOKE <PRIVILEGES> ON <PATHS> FROM ROLE/USER <NAME>;
eg: REVOKE READ ON root.** FROM ROLE role1;
eg: REVOKE READ_DATA, WRITE_DATA ON root.t1.** FROM USER user1;
eg: REVOKE READ_DATA, WRITE_DATA ON root.t1.**, root.t2.** FROM USER user1;
eg: REVOKE MANAGE_ROLE ON root.** FROM USER user1;
eg: REVOKE ALL ON root.** FROM USER user1;
```


#### Delete Time Partition (experimental)

```sql
Eg: DELETE PARTITION root.ln 0,1,2;
```

#### Continuous Query,CQ

```sql
Eg: CREATE CONTINUOUS QUERY cq1 BEGIN SELECT max_value(temperature) INTO temperature_max FROM root.ln.*.* GROUP BY time(10s) END;
```

#### Maintenance Command

- FLUSH

```sql
Eg: flush
```

- MERGE

```sql
Eg: MERGE;
Eg: FULL MERGE;
```

- CLEAR CACHE

```sql
Eg: CLEAR CACHE
```

- START REPAIR DATA

```sql
Eg: START REPAIR DATA
```

- STOP REPAIR DATA

```sql
Eg: STOP REPAIR DATA
```

- SET SYSTEM TO READONLY / WRITABLE

```sql
Eg: SET SYSTEM TO READONLY / WRITABLE
```

- Query abort

```sql
Eg: KILL QUERY 1
```