MySQL多表join时候update更新数据的方法

2022-11-12 09:24:54

内容摘要

这篇文章主要为大家详细介绍了MySQL多表join时候update更新数据的方法，具有一定的参考价值，可以用来参考一下。对此感兴趣的朋友，看看idc笔记做的技术笔记！sql语句：代码如下:

文章正文

这篇文章主要为大家详细介绍了MySQL多表join时候update更新数据的方法，具有一定的参考价值，可以用来参考一下。

对此感兴趣的朋友，看看idc笔记做的技术笔记！

sql语句：

代码如下:

<code>update item i,resource_library r,resource_review_link l set i.name=CONCAT('Review:',r.resource_name) where i.item_id=l.instance_id 
and l.level='item' and r.resource_id=l.resource_id and i.name=''
</code>

JOIN UPDATE & JOIN DELETE

代码如下:

<code> 
update a 
set a.schoolname = b.schoolname 
from tb_Std as a join tb_Sch as b on a.School = b.School 
where a.std_year = 2005 
go 
/* 
(2 row(s) affected) 
*/
select * 
from tb_Std as a join tb_Sch as b on a.School = b.School 
/* 
A School A A School 
2 2005 A A School A A School 
3 2004 C A School C C School 
4 2005 D D School D D School 
(4 row(s) affected) 
*/
</code>

代码如下:

<code> 
delete a 
from table1 a, table2 b 
where a.col1 = b.col1 
and a.col2 = b.col2 
</code>

The above SQL statement runs fine in SQL Server.If the Oracle 9i has different syntax or if there is any other way to accomplish this with a single delete statement that would be really helpful.> Hi,>> Is the following delete statement possible in Oracle 9i.>> delete a> from table1 a, table2 b> where a.col1 = b.col1> and a.col2 = b.col2>> The above SQL statement runs fine in SQL Server.>> If the Oracle 9i has different syntax or if there is any other way to accomplish this with a single delete statement that would be really helpful.>> Thanx in advance.>> -BheemBheem,Try this:DELETE FROM table1 a where exists (select 1 from table2 bwhere a.col1 = b.col1 and a.col2 = b.col2);Hope this helps,Tom K.

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代码注释

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作者：喵哥笔记

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