rowid 对应mysql_请教一下相当于MySQL中Oracle的RowID

在MySql中,通常使用会话变量来实现功能:

SELECT @rowid:=@rowid+1 as rowid

FROM table1, (SELECT @rowid:=0) as init

ORDER BY sorter_field

但是您无法在要从子查询中删除的表上进行排序。

UPD:也就是说,您将需要创建一个临时表,将测距子查询插入到该临时表中,并通过与临时表联接来从原始表中删除(您将需要一些唯一的行标识符):

CREATE TEMPORARY TABLE duplicates ...

INSERT INTO duplicates (rowid, field1, field2, some_row_uid)

SELECT

@rowid:=IF(@f1=field1 AND @f2=field2, @rowid+1, 0) as rowid,

@f1:=field1 as field1,

@f2:=field2 as field2,

some_row_uid

FROM testruns t, (SELECT @rowid:=NULL, @f1:=NULL, @f2:=NULL) as init

ORDER BY field1, field2 DESC;

DELETE FROM my_table USING my_table JOIN duplicates

ON my_table.some_row_uid = duplicates.some_row_uid AND duplicates.rowid > 0

由于这是一次操作,因此不会带来太多开销。


版权声明:本文为weixin_39928648原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接和本声明。