一：需求

A表和B表的表结构相同，A表是历史表，B表是增量数据表；想要根据关联条件更新A表中的数据。

二：表结构

CREATE TABLE `A` (

`id` bigint(20) NOT NULL AUTO_INCREMENT,

`bid` bigint(20) NOT NULL ,

`sid` bigint(20) NOT NULL ,

`grid` bigint(20) NOT NULL ,

`age` bigint(20) NOT NULL ,

`pv` bigint(20) NOT NULL ,

`uv` bigint(20) NOT NULL ,

`pay_count` bigint(20) NOT NULL,

`charge_amount` bigint(20) NOT NULL ,

`last_pay_count` bigint(20) NOT NULL ,

`last_charge_amount` bigint(20) NOT NULL ,

`ftime` bigint(20) NOT NULL ,

`dtime` bigint(20) NOT NULL DEFAULT ‘0‘ COMMENT ‘详细时间(yyyyMMddHH)‘

PRIMARY KEY (`id`,`ftime`),

KEY `IX_FTIME` (`ftime`) USING BTREE,

KEY `IX_HTIME` (`htime`) USING BTREE,

KEY `IX_DTIME` (`dtime`),

KEY `IX_B_F_S_G` (`bid`,`ftime`,`sid`,`grid`),

KEY `IX_B_S_G` (`bid`,`sid`,`grid`),

KEY `IX_B_D_S` (`bid`,`dtime`,`sid`)

) ENGINE=InnoDB  DEFAULT CHARSET=utf8;

注意：mysql 只有2种索引(BTREE 和 HASH)

三：注意

1、只更新A表的部分字段：pv、uv和pay_amount

2、确定唯一一条记录的关联字段是：bid、sid、dtime、qrid

四：实现

1、使用inner join实现

UPDATE A as aa

INNER JOIN B as bb ON bb.bid = aa.bid

AND bb.sid=aa.sid

AND bb.grid=aa.grid

SET aa.pv=bb.pv,

aa.uv=bb.uv,

aa.pay_amount=bb.pay_amount

WHERE aa.dtime=?

AND aa.bid=? ;

2、使用exists实现

UPDATE A aa

SET aa.pv = (SELECT bb.pv

FROM B bb

WHERE bb.bid = aa.bid

AND bb.sid = aa.sid

AND bb.grid = aa.grid),

aa.uv = (SELECT bb.uv

FROM B bb

WHERE bb.bid = aa.bid

AND bb.sid = aa.sid

AND bb.grid = aa.grid),

aa.pay_amount = (SELECT bb.pay_amount

FROM B bb

WHERE bb.bid = aa.bid

AND bb.sid = aa.sid

AND bb.grid = aa.grid)

WHERE EXISTS (SELECT 1

FROM B bb

WHERE bb.bid = aa.bid

AND bb.sid = aa.sid

AND bb.grid = aa.grid)

AND aa.dtime = ?

AND aa.bid = ?;