Question

MySQL三表联合查询

如图三个表都是一样的，分别为 student，teacher，admin，现在我要查询这三个表中字段GH为 特定值 的PWD,GH,QX字段，sql语句该如何写，十分感谢。

Answer 1

select PWD,GH,QX from student where GH = '特定值';

追问

这只查了student表的字段，还有两个表的没查，能不能同时在三个表里查 GH=“特定值”的字段

追答

select PWD,GH,QX from student where GH = '特定值'
union all (select PWD,GH,QX from teacher where GH = '特定值')
union all (select PWD,GH,QX from admin where GH = '特定值')