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

1. 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     |            |         |
+-------+-----------------+-----------+------+------+---------+---------+------------+---------+

2. 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     |
+-------+-----------------+------+------+---------+---------+