mysql怎么查重复记录 mysql怎么查出重复的数据

mysql 怎样找出重复的记录

SQL语句：SELECT `lcontent` FROM `caiji_ym_liuyan`这样查询的时候就会有很多重复的记录

例子：

就会出现这样的重复

2

修改后的SQL语句：

SELECT distinct(`lcontent`) FROM `caiji_ym_liuyan`

查询结果：

mysql去重复 保留一条

mysql去重复 保留一条怎么操作呢？一起来看下吧：

1、查找表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断

SELECT     * FROM     people WHERE     peopleId IN (         SELECT             peopleId         FROM             people         GROUP BY             peopleId         HAVING             count(peopleId)  1     )

2、删除表中多余的重复记录，重复记录是根据单个字段（peopleId）来判断，只留有rowid最小的记录

DELETE FROM     people WHERE     peopleName IN (         SELECT             peopleName         FROM             people         GROUP BY             peopleName         HAVING             count(peopleName)  1     ) AND peopleId NOT IN (     SELECT         min(peopleId)     FROM         people     GROUP BY         peopleName     HAVING         count(peopleName)  1 )

3、查找表中多余的重复记录（多个字段）

SELECT     * FROM     vitae a WHERE     (a.peopleId, a.seq) IN (         SELECT             peopleId,             seq         FROM             vitae         GROUP BY             peopleId,             seq         HAVING             count(*)  1     )

4、删除表中多余的重复记录（多个字段），只留有rowid最小的记录

DELETE FROM     vitae a WHERE     (a.peopleId, a.seq) IN (         SELECT             peopleId,             seq         FROM             vitae         GROUP BY             peopleId,             seq         HAVING             count(*)  1     ) AND rowid NOT IN (     SELECT         min(rowid)     FROM         vitae     GROUP BY         peopleId,         seq     HAVING         count(*)  1 )

5、查找表中多余的重复记录（多个字段），不包含rowid最小的记录

SELECT     * FROM     vitae a WHERE     (a.peopleId, a.seq) IN (         SELECT             peopleId,             seq         FROM             vitae         GROUP BY             peopleId,             seq         HAVING             count(*)  1     ) AND rowid NOT IN (     SELECT         min(rowid)     FROM         vitae     GROUP BY         peopleId,         seq     HAVING         count(*)  1 )

6、消除一个字段的左边的第一位：

UPDATE tableName SET [ Title ]= RIGHT ([ Title ],(len([ Title ]) - 1)) WHERE     Title LIKE '村%'

7、消除一个字段的右边的第一位：

UPDATE tableName SET [ Title ]= LEFT ([ Title ],(len([ Title ]) - 1)) WHERE     Title LIKE '%村'

8、假删除表中多余的重复记录（多个字段），不包含rowid最小的记录

UPDATE vitae SET ispass =- 1 WHERE     peopleId IN (         SELECT             peopleId         FROM             vitae         GROUP BY             peopleId

mysql查询某字段相同的记录

select * from 表名 where match_id in (select match_id from 表名 where team_id='a' or team_id='b' group by match_id)

mysql如何查询重复记录

select * from tableName where (bookname,borrowtime) in (select bookname,borrowtime from tableName group by bookname,borrowtime having count(*)  1);

MySql怎么查询重复的数据

select name,sum(num) from table group by name

--group by 分组查询可以实现，根据名称分组查询累加数量

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