目录SQL UNION运算符演示数据库SQL UNION示例SQL UNION ALL示例带有WHERE的SQL UNION带有WHERE的SQL UNION ALL另一个UNION示例SQL GROUP BY语句演示数据库SQL GROUP BY示例演示数据库带有JOIN的GROUP BY示例SQL UNIO
This question is related to another I ask recently, it can be found here for some background information.