SHOW COLUMNS
Description
This statement is used to specify the column information of a table.
Syntax
SHOW [ FULL ] COLUMNS FROM <tbl>;
Required Parameters
1. <tbl>
The name of the table for which column information needs to be viewed must be specified.
Optional Parameters
1. FULL
If the FULL keyword is specified, detailed information about the columns will be returned, including the aggregation type, permissions, comments, etc. of the columns.
Return Value
| Column | DataType | Note |
|---|---|---|
| Field | varchar | Column Name |
| Type | varchar | Column Data Type |
| Collation | varchar | Column Collation |
| Null | varchar | Whether NULL is Allowed |
| Key | varchar | Table's Primary Key |
| Default | varchar | Default Value |
| Extra | varchar | Extra Info |
| Privileges | varchar | Column Privileges |
| Comment | varchar | Column Comment |
Access Control Requirements
Requires the SHOW privilege for the table to be viewed.
Examples
- View detailed column information of the specified table
SHOW FULL COLUMNS FROM t_agg;
+-------+-----------------+-----------+------+------+---------+---------+------------+---------+
| Field | Type | Collation | Null | Key | Default | Extra | Privileges | Comment |
+-------+-----------------+-----------+------+------+---------+---------+------------+---------+
| k1 | tinyint | | YES | YES | NULL | | | |
| k2 | decimalv3(10,2) | | YES | YES | 10.5 | | | |
| v1 | char(10) | | YES | NO | NULL | REPLACE | | |
| v2 | int | | YES | NO | NULL | SUM | | |
+-------+-----------------+-----------+------+------+---------+---------+------------+---------+
- View the normal column information of the specified table
SHOW COLUMNS FROM t_agg;
+-------+-----------------+------+------+---------+---------+
| Field | Type | Null | Key | Default | Extra |
+-------+-----------------+------+------+---------+---------+
| k1 | tinyint | YES | YES | NULL | |
| k2 | decimalv3(10,2) | YES | YES | 10.5 | |
| v1 | char(10) | YES | NO | NULL | REPLACE |
| v2 | int | YES | NO | NULL | SUM |
+-------+-----------------+------+------+---------+---------+
