sql查询表内重复数据

语法如下: SELECT [字段名],COUNT(1) FROM [表名] Group By [字段名] Having Count(1) > 1 如下图所示,我们要查询表内年龄重复的个数 SELECT Age,COUNT(1) AS RepeatData FROM Student Group by Age having COUNT(1)>1 Group by :根据什么进行分组,上面那句话的意思就是根据 Age 分组: Having:筛选满足条件的组,就是在分组之后过滤数据:查询结果为什么没有

1.如表中没有主键,先添加自动增长主键 alter table 表名 add 列名 int identity (1,1) primary key 2.删除重复数据 delete from 表名 where id not in (select min(id) from 表名 group by id)

数据库环境:SQL SERVER 2005 现有一个表的数据如下,id是主键,p1,p2是字符串类型,如果当前行的p1,p2字段的值分别等于其它行 的字段p2,p1的值,则视这2行记录为一组.比如,id=1和id=5就属于同一组数据.同一组数据只显示id最小 的那行记录,没有组的数据全部显示. 实现思路: 将表进行自关联左联,假设表的别名是a,b,根据id进行关联,对关联后的结果集进行过滤.如果b.id是空的,则保留, 如果b.id不为空,则只保留a.id比b.id小的记录. 实现的SQL脚本:

数据库UserInfo 删除重复数据 即删除重复的用户名手机号 同一个用户名手机号只保留一个用户 01.根据多个字段查询重复数据 with data1 as( select MobilePhone,Name from UserInfogroup by MobilePhone,Namehaving count(*)>1 ), 02.对重复数据分配编号 data2 as ( select u.*,row_number() over(partition by u.MobilePhone,u.Name

sql不重复的查找统计数据2007-06-29 11:04例表如下: 表名:MYTEST TID    COL1    COL2     COL3 1           1           A            A 2           1           A            A 3           2           A            A 4           2           B            A 5           3       

查询及删除重复记录的方法(一)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 peoplewhere 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,只留有一个记录delete from peoplewhere peopleId in (s

1.查询单列重复: 1 select * from test 2 where name in (select name from Y_ShipOrder group by name having count 3 (name) > 1) 2.查询多列重复 1 SELECT a.* FROM test a,( 2 SELECT name,code 3 FROM test 4 GROUP BY name,code 5 HAVING COUNT(1)>1 6 7 ) AS b 8 WHERE a.na

<span style="font-family:Microsoft YaHei;font-size:18px;">select tt1.LSH from (select t1.zblsh,t1.lsh, row_number() over(partition by t1.ZBLSH order by t1.XT_XGRQ desc) rn from grjx_zbgl_bhgzl t1 WHERE t1.nf = '2015' ) tt1 where tt1.rn <

SELECT * FROM user WHERE Uid IN ( select min(Uid) from user group by Sid ) 原文地址:https://www.cnblogs.com/gjack/p/10326651.html