Oracle merge into 的用法详解实例
作用:
merge into 解决用B表跟新A表数据,如果A表中没有,则把B表的数据插入A表;
语法:
MERGE INTO [your table-name] [rename your table here]
USING ( [write your query here] )[rename your query-sql and using just like a table]
ON ([conditional expression here] AND [...]...)
WHEN MATHED THEN [here you can execute some update sql or something else ]
WHEN NOT MATHED THEN [execute something else here ! ]
-------实例-------
merge into a
using (select id,name from b ) c
on(a.id=c.id )
when matched then update set a.name=c.name
when not matched then insert (a.id,a.name) values (c.id,c.name);
作用:利用表 b 跟新表a ,条件是a.id=b.id,如果a表中没有该条件的数据就插入。
如果你的数据量很大,此sql效率非常高。
--转自