BEGIN DELETE TB FROM TableName TB WHERE TB.ID IN (SELECT MIN(ID) FROM TableName TB2 GROUP BY TB2.Column1,TB2.Column2,...TB2.ColumnN ) ); SET @Count = @@ROWCOUNT; END 这里使用了循环删除,并不是最优的方法,欢迎园友不吝批评指正. 其实还有一种方法是先查询重复的数据,然后在重复数据中保留一条. 下面用例子说明. 例如表City有如下的数
在网上看过一些解决方法 我在此给出的方法适用于无唯一ID的情形 表:TB_MACVideoAndPicture 字段只有2个:mac,content mac作为ID,正常情况下mac数据是唯一的,由于操作失误导致数据插入多次,导致出现多个mac,content重复数据,现在只保留一条,删除多余的 大体思想是给重复数据一个自增ID,过滤出每组里面最小ID,删除原数据中所有重复数据再将最小ID插入 --查询出所有重复数据,并给定递增id , ) AS id , mac , content INTO
删除表中重复数据,留下ID比较小的行 delete from 表 where [重复字段] in (select [重复字段] from 表 group by 字段 having count([字段]) > 1) and ID not in (select min(ID) from [表] group by [字段] having count([字段])> 1)
数据库操作中,经常会因为导数据造成数据重复,需要进行数据清理,去掉冗余的数据,只保留正确的数据 一:重复数据根据单个字段进行判断 1.首先,查询表中多余的数据,由关键字段(name)来查询. select * from table_name where name in (select name from table_name group by name having count(name)>1) 2.删除表中重复数据,重复数据是根据单个字段(name)来判断,只留有rowid最小的记录
SELECT * FROM (SELECT addTime FROM motorcade.car_msg_info GROUP BY addTime HAVING COUNT(addTime) > 1) AS b) AND ID NOT IN (SELECT * FROM (SELECT MIN(ID) FROM motorcade.car_msg_info GROUP BY addTime HAVING COUNT(addTime) > 1) AS c) delete from people
比如,某个表要按照id和name重复,就算重复数据 delete from 表名 where rowid not in (select min(rowid) from 表名 group by id,name); commit; 如果以id,name和grade重复算作重复数据 delete from 表名 where rowid not in (select min(rowid) from 表名 group by id,name,grade); commit; 注意 min也可以换成max
方法一:使用在T-SQL的编程中 分配一个列号码,以COL1,COL2组合来分区排序,删除DATABASE重复的行(重复数据),只保留一行 // COL1,COL2是数据库DATABASE的栏位 delete a from (select COL1,COL2,row_number() over (partition by COL1,COL2 order by COL1) as rn from DATABASE) a where a.rn>1 方法二:使用在ETL中 select distant
1. 查询SQL表中某个字段的重复数据 SELECT user_name,COUNT(*) AS count FROM db_user_info GROUP BY user_name HAVING count > 1; SELECT user_name FROM db_user_info GROUP BY user_name HAVING COUNT(1) > 1; SELECT * FROM db_user_info WHERE user_name IN (SELECT user_name
SQL查询语句,怎样查询重复数据 2012-02-22 14:50神奇的马骁勇 | 浏览 0 次 有表A, 中有字段id, name, memo现在有很多id重复的数据,怎么把这些重复的都查出来?group by? 请写出SQL语句, 谢谢 提问者采纳 select id, name, memofrom Awhere id in (select id from A group by id having count(1) >= 2)
Access数据库删除重复记录,只保留一条记录的做法: 只保留id最小的记录方法: delete from [表名] where id not in (select min(id) from [表名] group by [带重复记录的字段名称]) 只保留id最大的记录方法: delete from [表名] where id not in (select max(id) from [表名] group by [带重复记录的字段名称])
delete from 表名 where id not in (select d.id from (SELECT id FROM 表名 GROUP BY c1,c2,c3,c4)as d) #去重复,把url重复,且区为空的中去掉.select * from TABLE where url in (select u.url from (select * from TABLE where id not in (select d.id from (SELECT id FROM TABLE GROUP
问题背景 在一个多表查询的sql中正常情况下产生的数据都是唯一的,但因为数据库中存在错误(某张表中存在相同的外键ID)导致我这边查询出来的数据就会有重复的问题 下面结果集中UserID:15834存在多个 查询Sql如下: SELECT * FROM ( SELECT ROW_NUMBER() OVER ( ORDER BY T.USERID asc )AS Row ,T.USERID ,T.CreateTime FROM UserInfo T LEFT JOIN DiseaseInfo i
(一)单个字段 1.查找表中多余的重复记录,根据(question_title)字段来判断 代码如下 复制代码 select * from questions where question_title in (select question_title from people group by question_title having count(question_title) > 1) 2.删除表中多余的重复记录,根据(question_title)字段来判断,只留有一个记录 代码如下 复制