假如有表t1,t2,t3,三个表结构完全相同,怎样能够一次取出这三个表里面的内容?用存储过程写的话?
(select * from t1) union (select * from t2) union (select * from t3)
如果表结构一样,可以用union将结果连接起来。
select * from t1 union select * from t2 union select * from t3
如果表结构一样,可以用union将结果连接起来。
select * from t1 union select * from t2 union select * from t3