mysql三表查询 mysql三表联合查询

select * from table1 a,table2 b,table3 c where a.1id = b.1id inner join a.1id = c.2id;

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

select * from table1 t1,table2 t2,table3 t3 where t1.id=t2.id and t1.id=t3.id

select *from travelerinfo t1 left join tickorderinfo t2 on t1.orderId=t2.orderId left join pnrauth t3 on t2.tickOrderId=t3.tickOrderIdwhere t2.status=28 and t3.authPCC='ABC'order by t1.orderidlimit 1000

建议你三表联合查询.编程时首选语句简单、逻辑清晰的方式,其次是尽量减少查询的次数、网络交换的数据量,查询的效率应该通过合适的索引优化到最佳.

使用UNION联合两个语句即可:select * from a where cid=1 UNION select * from b where cid=1

select a.*, b.*, c.* from tablea as aleft join tableb as b on a.xx = b.xxleft join tableb as c on b.xx = c.xx

如果a是唯一的话那就select table1.id,table2.id,table3.id from table1,table2,table3 where table1.a='12' and table1.a=table2.a and table2.a=table3.a;或者如果对下你给数据相同的话,可以用union 连接 在用一个标志位,区分三张表!

从存储过程返回表类型的值也有二种:1.存储过程使用浮标参数,即同时指定cursor varying output项.调用者可以使用while及fetch循环遍历该浮标.2.直接将存储过程返回的.

这样写:SELECT S.SName AS 姓名, CS.CourseName AS 课程, C.Score AS 成. (CS.CourseID = C.CourseID 扩展资料:SQL联合查询的分类 一、内连接查询:只查.