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add colimns function in table select (#714)
* add colimns function in table select * add colimns function in table select
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Lines changed: 490 additions & 2 deletions

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‎src/UserGuide/Master/Table/SQL-Manual/Select-Clause.md‎

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- It supports aggregate functions (e.g., `SUM`, `AVG`, `COUNT`) and window functions, logically executed last in the query process.
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- DISTINCT Keyword: `SELECT DISTINCT column_name` ensures that the values in the query results are unique, removing duplicates.
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- COLUMNS Function: The COLUMNS function is supported in the SELECT clause for column filtering. It can be combined with expressions, allowing the expression's logic to apply to all columns selected by the function.
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## 2. Detailed Syntax:
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3. **AGROUP BY Clause**: Use ALL and DISTINCT quantifiers in the GROUP BY clause to determine whether each duplicate grouping set produces distinct output rows.
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`COLUMNS` Function:
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1. **`COLUMNS(*)`**: Matches all columns and supports combining with expressions.
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2. **`COLUMNS(regexStr) ? AS identifier`**: Regular expression matching
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- Selects columns whose names match the specified regular expression `(regexStr)` and supports combining with expressions.
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- Allows renaming columns by referencing groups captured by the regular expression. If `AS` is omitted, the original column name is displayed in the format `_coln_original_name` (where `n` is the column’s position in the result table).
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- Renaming Syntax:
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- Use parentheses () in regexStr to define capture groups.
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- Reference captured groups in identifier using `'$index'`.
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- Note: The identifier must be enclosed in double quotes if it contains special characters like `$`.
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## 3. Example Data
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262274
It costs 0.189s
263275
```
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### 3.2 Colums Function
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1. Without combining expressions
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```sql
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-- Query data from columns whose names start with 'm'
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IoTDB:database1> select columns('^m.*') from table1 limit 5
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+--------+-----------+
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|model_id|maintenance|
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+--------+-----------+
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| E| 180|
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| E| 180|
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| C| 90|
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| C| 90|
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| C| 90|
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+--------+-----------+
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-- Query columns whose names start with 'o' - throw an exception if no columns match
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IoTDB:database1> select columns('^o.*') from table1 limit 5
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Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 701: No matching columns found that match regex '^o.*'
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-- Query data from columns whose names start with 'm' and rename them with 'series_' prefix
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IoTDB:database1> select columns('^m(.*)') AS "series_$0" from table1 limit 5
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+---------------+------------------+
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|series_model_id|series_maintenance|
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+---------------+------------------+
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| E| 180|
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| E| 180|
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| C| 90|
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| C| 90|
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| C| 90|
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+---------------+------------------+
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```
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2. With Expression Combination
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- Single COLUMNS Function
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```sql
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-- Query the minimum value of all columns
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IoTDB:database1> select min(columns(*)) from table1
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+-----------------------------+------------+--------------+---------------+--------------+-----------------+-----------------+--------------+------------+-----------------------------+
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| _col0_time|_col1_region|_col2_plant_id|_col3_device_id|_col4_model_id|_col5_maintenance|_col6_temperature|_col7_humidity|_col8_status| _col9_arrival_time|
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+-----------------------------+------------+--------------+---------------+--------------+-----------------+-----------------+--------------+------------+-----------------------------+
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|2024-11-26T13:37:00.000+08:00| 上海| 1001| 100| A| 180| 85.0| 34.8| false|2024-11-26T13:37:34.000+08:00|
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+-----------------------------+------------+--------------+---------------+--------------+-----------------+-----------------+--------------+------------+-----------------------------+
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```
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- Multiple COLUMNS Functions in Same Expression
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> Usage Restriction: When multiple COLUMNS functions appear in the same expression, their parameters must be identical.
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```sql
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-- Query the sum of minimum and maximum values for columns starting with 'h'
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IoTDB:database1> select min(columns('^h.*')) + max(columns('^h.*')) from table1
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+--------------+
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|_col0_humidity|
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+--------------+
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| 79.899994|
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+--------------+
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-- Error Case: Non-Identical COLUMNS Functions
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IoTDB:database1> select min(columns('^h.*')) + max(columns('^t.*')) from table1
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Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 701: Multiple different COLUMNS in the same expression are not supported
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```
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- Multiple COLUMNS Functions in Different Expressions
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```sql
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-- Query minimum of 'h'-columns and maximum of 'h'-columns separately
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IoTDB:database1> select min(columns('^h.*')) , max(columns('^h.*')) from table1
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+--------------+--------------+
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|_col0_humidity|_col1_humidity|
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+--------------+--------------+
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| 34.8| 45.1|
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+--------------+--------------+
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-- Query minimum of 'h'-columns and maximum of 'te'-columns
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IoTDB:database1> select min(columns('^h.*')) , max(columns('^te.*')) from table1
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+--------------+-----------------+
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|_col0_humidity|_col1_temperature|
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+--------------+-----------------+
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| 34.8| 90.0|
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+--------------+-----------------+
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```
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3. In Where Clause
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```sql
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-- Query data where all 'h'-columns must be > 40 (equivalent to)
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IoTDB:database1> select * from table1 where columns('^h.*') > 40
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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| time|region|plant_id|device_id|model_id|maintenance|temperature|humidity|status| arrival_time|
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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|2024-11-29T11:00:00.000+08:00| 上海| 3002| 100| E| 180| null| 45.1| true| null|
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|2024-11-28T09:00:00.000+08:00| 上海| 3001| 100| C| 90| null| 40.9| true| null|
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|2024-11-28T11:00:00.000+08:00| 上海| 3001| 100| C| 90| 88.0| 45.1| true|2024-11-28T11:00:12.000+08:00|
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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--Alternative syntax
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IoTDB:database1> select * from table1 where humidity > 40
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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| time|region|plant_id|device_id|model_id|maintenance|temperature|humidity|status| arrival_time|
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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|2024-11-29T11:00:00.000+08:00| 上海| 3002| 100| E| 180| null| 45.1| true| null|
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|2024-11-28T09:00:00.000+08:00| 上海| 3001| 100| C| 90| null| 40.9| true| null|
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|2024-11-28T11:00:00.000+08:00| 上海| 3001| 100| C| 90| 88.0| 45.1| true|2024-11-28T11:00:12.000+08:00|
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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```
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## 4. Column Order in the Result Set
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- **Column Order**: The order of columns in the result set matches the order specified in the `SELECT` clause.

‎src/UserGuide/latest-Table/SQL-Manual/Select-Clause.md‎

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# SELECT Clauses
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**SELECT Clause** specifies the columns included in the query results.
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**SELECT Clause** specifies the columns included in the query results.
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## 1. Syntax Overview
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4141

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- It supports aggregate functions (e.g., `SUM`, `AVG`, `COUNT`) and window functions, logically executed last in the query process.
4343
- DISTINCT Keyword: `SELECT DISTINCT column_name` ensures that the values in the query results are unique, removing duplicates.
44+
- COLUMNS Function: The COLUMNS function is supported in the SELECT clause for column filtering. It can be combined with expressions, allowing the expression's logic to apply to all columns selected by the function.
4445

4546
## 2. Detailed Syntax:
4647

@@ -58,6 +59,17 @@ Usage scenarios for DISTINCT:
5859

5960
3. **AGROUP BY Clause**: Use ALL and DISTINCT quantifiers in the GROUP BY clause to determine whether each duplicate grouping set produces distinct output rows.
6061

62+
`COLUMNS` Function:
63+
64+
1. **`COLUMNS(*)`**: Matches all columns and supports combining with expressions.
65+
2. **`COLUMNS(regexStr) ? AS identifier`**: Regular expression matching
66+
- Selects columns whose names match the specified regular expression `(regexStr)` and supports combining with expressions.
67+
- Allows renaming columns by referencing groups captured by the regular expression. If `AS` is omitted, the original column name is displayed in the format `_coln_original_name` (where `n` is the column’s position in the result table).
68+
- Renaming Syntax:
69+
- Use parentheses () in regexStr to define capture groups.
70+
- Reference captured groups in identifier using `'$index'`.
71+
- Note: The identifier must be enclosed in double quotes if it contains special characters like `$`.
72+
6173
## 3. Example Data
6274

6375

@@ -262,6 +274,116 @@ Total line number = 18
262274
It costs 0.189s
263275
```
264276

277+
### 3.2 Colums Function
278+
279+
1. Without combining expressions
280+
```sql
281+
-- Query data from columns whose names start with 'm'
282+
IoTDB:database1> select columns('^m.*') from table1 limit 5
283+
+--------+-----------+
284+
|model_id|maintenance|
285+
+--------+-----------+
286+
| E| 180|
287+
| E| 180|
288+
| C| 90|
289+
| C| 90|
290+
| C| 90|
291+
+--------+-----------+
292+
293+
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-- Query columns whose names start with 'o' - throw an exception if no columns match
295+
IoTDB:database1> select columns('^o.*') from table1 limit 5
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Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 701: No matching columns found that match regex '^o.*'
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298+
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-- Query data from columns whose names start with 'm' and rename them with 'series_' prefix
300+
IoTDB:database1> select columns('^m(.*)') AS "series_$0" from table1 limit 5
301+
+---------------+------------------+
302+
|series_model_id|series_maintenance|
303+
+---------------+------------------+
304+
| E| 180|
305+
| E| 180|
306+
| C| 90|
307+
| C| 90|
308+
| C| 90|
309+
+---------------+------------------+
310+
```
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312+
2. With Expression Combination
313+
314+
- Single COLUMNS Function
315+
```sql
316+
-- Query the minimum value of all columns
317+
IoTDB:database1> select min(columns(*)) from table1
318+
+-----------------------------+------------+--------------+---------------+--------------+-----------------+-----------------+--------------+------------+-----------------------------+
319+
| _col0_time|_col1_region|_col2_plant_id|_col3_device_id|_col4_model_id|_col5_maintenance|_col6_temperature|_col7_humidity|_col8_status| _col9_arrival_time|
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+-----------------------------+------------+--------------+---------------+--------------+-----------------+-----------------+--------------+------------+-----------------------------+
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|2024-11-26T13:37:00.000+08:00| 上海| 1001| 100| A| 180| 85.0| 34.8| false|2024-11-26T13:37:34.000+08:00|
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+-----------------------------+------------+--------------+---------------+--------------+-----------------+-----------------+--------------+------------+-----------------------------+
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```
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- Multiple COLUMNS Functions in Same Expression
326+
327+
> Usage Restriction: When multiple COLUMNS functions appear in the same expression, their parameters must be identical.
328+
329+
```sql
330+
-- Query the sum of minimum and maximum values for columns starting with 'h'
331+
IoTDB:database1> select min(columns('^h.*')) + max(columns('^h.*')) from table1
332+
+--------------+
333+
|_col0_humidity|
334+
+--------------+
335+
| 79.899994|
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+--------------+
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-- Error Case: Non-Identical COLUMNS Functions
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IoTDB:database1> select min(columns('^h.*')) + max(columns('^t.*')) from table1
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Msg: org.apache.iotdb.jdbc.IoTDBSQLException: 701: Multiple different COLUMNS in the same expression are not supported
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```
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- Multiple COLUMNS Functions in Different Expressions
344+
345+
```sql
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-- Query minimum of 'h'-columns and maximum of 'h'-columns separately
347+
IoTDB:database1> select min(columns('^h.*')) , max(columns('^h.*')) from table1
348+
+--------------+--------------+
349+
|_col0_humidity|_col1_humidity|
350+
+--------------+--------------+
351+
| 34.8| 45.1|
352+
+--------------+--------------+
353+
354+
-- Query minimum of 'h'-columns and maximum of 'te'-columns
355+
IoTDB:database1> select min(columns('^h.*')) , max(columns('^te.*')) from table1
356+
+--------------+-----------------+
357+
|_col0_humidity|_col1_temperature|
358+
+--------------+-----------------+
359+
| 34.8| 90.0|
360+
+--------------+-----------------+
361+
```
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3. In Where Clause
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```sql
366+
-- Query data where all 'h'-columns must be > 40 (equivalent to)
367+
IoTDB:database1> select * from table1 where columns('^h.*') > 40
368+
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
369+
| time|region|plant_id|device_id|model_id|maintenance|temperature|humidity|status| arrival_time|
370+
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
371+
|2024-11-29T11:00:00.000+08:00| 上海| 3002| 100| E| 180| null| 45.1| true| null|
372+
|2024-11-28T09:00:00.000+08:00| 上海| 3001| 100| C| 90| null| 40.9| true| null|
373+
|2024-11-28T11:00:00.000+08:00| 上海| 3001| 100| C| 90| 88.0| 45.1| true|2024-11-28T11:00:12.000+08:00|
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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--Alternative syntax
377+
IoTDB:database1> select * from table1 where humidity > 40
378+
+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
379+
| time|region|plant_id|device_id|model_id|maintenance|temperature|humidity|status| arrival_time|
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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|2024-11-29T11:00:00.000+08:00| 上海| 3002| 100| E| 180| null| 45.1| true| null|
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|2024-11-28T09:00:00.000+08:00| 上海| 3001| 100| C| 90| null| 40.9| true| null|
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|2024-11-28T11:00:00.000+08:00| 上海| 3001| 100| C| 90| 88.0| 45.1| true|2024-11-28T11:00:12.000+08:00|
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+-----------------------------+------+--------+---------+--------+-----------+-----------+--------+------+-----------------------------+
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```
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## 4. Column Order in the Result Set
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267389
- **Column Order**: The order of columns in the result set matches the order specified in the `SELECT` clause.

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