查库: show databases; select schema_name from information_schema.schemata; 查表: show tables; select table_name from information_schema.tables where table_schema=‘security’; 查列: select * from users; select column_name from information_schema.columns where table_name=‘users’; 查字段: select username,password from security.users; (这里以security数据库中,users表中,username,password列为例) —————————————————————————————