转:mysql 各种级联查询后更新(update select)


mysql 各种级联查询后更新(update select).

CREATE TABLE `tb1` (
`id` int(11) NOT NULL,
`A` varchar(100) default NULL,
`B` varchar(100) default NULL,
`C` varchar(20) default NULL,
PRIMARY KEY (`id`),
KEY `id` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

CREATE TABLE `tb2` (
`id` int(11) NOT NULL,
`A` varchar(100) default NULL,
`B` varchar(100) default NULL,
PRIMARY KEY (`id`),
KEY `id` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

级联更新1:

update tb1,
tb2
set tb1.a=tb2.a,tb1.b=tb2.b
where tb1.id=tb2.id

级联更新2:

update tb1,
(select * from tb2) as tb2
set tb1.a=tb2.a,tb1.b=tb2.b
where tb1.id=tb2.id

级联更新3:

update (select * from tb1 group by C) as temp,
tb2,
tb1
set tb1.a = tb2.a,
tb1.b = tb2.b
where tb1.id = tb2.id and
temp.id = tb2.id

级联更新4:

update tb1 left join tb2 on tb1.id = tb2.id
set tb1.a = tb2.a,
tb1.b = tb2.b
where ……

http://blog.csdn.net/wslyy99/article/details/4336602

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