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求sql语句,mysql多对多查询

select * from (select id,sum(money) as mm from a表 group by id) aaa, (select id,sum(money) as nn from b表 group by id) bbb where aaa.id=bbb.id and aaa.mm=bbb.nn; ----------------------------- 说明: 先用语句,得到aaa,bbb两个临...

一使用SELECT子句进行多表查询 SELECT 字段名 FROM 表1,表2 … WHERE 表1.字段 = 表2.字段 AND 其它查询条件 SELECT a.id,a.name,a.address,a.date,b.math,b.english,b.chinese FROM tb_demo065_tel AS b,tb_demo065 AS a WHERE a.id=b.id 注:在...

在每条sql语句的后面加上;号,即可同时执行多条语句。

select col1,col2,col3 from test ; 像这种将需要查询出的字段名列举出来即可, 欢迎追问,满意请采纳

1. 子查询方法 select * from DB2.table2 where 字段 in (select table1中相应字段 from DB1.table1 where table1中相应字段=相应值) 2. 左连接方法 select table2.* from DB2.table2 left join DB1.table1 on table1.字段 = table2.相应字段 wh...

不知道你说的执行多条sql语句具体是什么,我理解为查多个表的数据,可以用联合查询,例如: select * from a order by id union select * from b order id;

不知道你的a,b两表有没有关联,假定没有关联 select count(1)from (select idfrom a where id>5union allselect id from b where id>5)

1先通过status命令查看Mysql运行状态 mysql> status; -------------- mysql Ver 14.14 Distrib 5.1.73, for redhat-linux-gnu (x86_64) using readline 5.1 Connection id: 113752 Current database: information_schema Current user: push_use...

select * from `order` r inner join (select order_id ,sum(cost) as c from order_details ) as x on r.order_id = x.order_id where r.subtotal x.c 或 select * from 'order' r where r.subtotal (select sum(cost) from order_details d wh...

selectt1.id,t1.from_uid,t2.name as from_name,t1.to_uid,t3.name as to_name,t1.contentfromchat t1,user t2,user t3where 1=1and t1.from_uid = t2.idand t1.to_uid = t3.idand t2.name in ('张三', '李四')and t3.name in ('张三', '李四')...

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