mysql一库多表查询主键

mysql> show databases;

mysql> use information_schema;

mysql> show tables;

mysql> select * from KEY_COLUMN_USAGE;    //查询每个库里每个表的信息

mysql> select * from KEY_COLUMN_USAGE where TABLE_SCHEMA='table_name' and CONSTRAINT_NAME='PRIMARY';  //根据条件查询需要的表格