sql判斷表字段是否存在

mysql

1、判斷乙個表是否存在

語法：select table_name from information_schema.tables where table_name ='表名';

sql例子：

select table_name from information_schema.tables where table_name ='t_iov_vehicle_owner_info'

存在：

不存在：

備註，sql也可以這樣寫：

select count(*) from information_schema.tables where table_name='t_iov_vehicle_owner_info'

2、判斷表中乙個字段是否存在語法：select count(*) from information_schema.columns where table_name = '表名' and column_name = '欄位名'

sql例子：

select count(*) from information_schema.columns where table_name = 't_iov_vehicle_owner_info' and column_name = 'id'

存在：

不存在：

知識點延伸：

1、mssql server

表：select count(*) from dbo.sysobjects where name= 'table_name'；

字段：select count(*) from syscolumns where id=object_id(『table_name』) and name= 'column_name'；

2、oracle

表：select count(*) from user_objects where object_name = 'table_name'；

字段：select count(*) from user_tab_columns where table_name = 'table_name' and column_name = 'column_name'；

3、postgresql

表：select count(*) from information_schema.tables where table_schema='table_schema' and table_name ='table_name'；

字段：select count(*) from information_schema.columns where table_schema='table_schema' and table_name ='table_name' and column_name='column_name'；

sql判斷表 字段是否存在