Mysql判断表字段是否存在；MySQL判断数据表是否存在

1、判断表字段是否存在

根据系统表 information_schema.columns

select count(*) from information_schema.columns 
where 
table_name = 'user_power_back' 
and 
column_name = 'user_id';

还可以加强判断为哪个数据库的表字段

SELECT count(*) from information_schema.columns 
WHERE 
table_name = 'user_power_back' 
AND 
column_name = 'user_id'AND table_schema='config_center';

2、判断表是否存在

根据系统表 information_schema.TABLES

SELECT * FROM information_schema.TABLES WHERE table_name ='crontab_config' AND table_schema='config_center';