数据仓库服务 GAUSSDB(DWS)-注释信息函数:col_description(table_oid, column_number)

时间：2024-06-29 17:51:35

col_description(table_oid, column_number)

描述：获取一个表字段的注释。

返回类型：text

备注：col_description返回一个表中字段的注释，通过表OID和字段号来声明。

示例：查询pg_class系统表获取表OID，查询INFORMATION_SCHEMA.COLUMNS系统视图获取column_number。

  
       SELECT COLUMN_NAME,ORDINAL_POSITION FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 't' AND COLUMN_NAME = 'a';
column_name | ordinal_position
-------------+------------------
a           |                1
(1 row)

SELECT oid FROM pg_class WHERE relname='t';
  oid
-------
 44020
(1 row)

SELECT col_description(44020,1);
    col_description
-----------------------
 This is a test table.
(1 row)