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sql 查询时如何去掉重复的部分写在whErE中

select col1,col2,col3 from (select col1,col2,col3, row_number() over(partition by col1 order by col2 desc) rn from table_name ) a where rn=1

关键字Distinct 去除重复 如下列SQL,去除Test相同的记录; select distinct Test from Table 如果是要删除表中存在的重复记录,那就逻辑处理,如下: select Test from Table group by Test having count(test)>1 先查询存在重复的数据,后面...

SELECT * FROM 表名 WHERE ROWID IN ( SELECT MIN(ROWID) FROM 表名 GROUP BY 列1, 列2, 列3 ) 如果不是Oracle数据库,可以将ROWID替换为主键来进行。

having 主要用于聚合函数的 条件 比如 查询 总数 A

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...

sqlserver: with t as ( select top 300 row_number() over(order by 字段) r, * from 表) select * from t where r>=200 oracle: with t as ( select rownum r, * from 表 where rownum=200 mysql: select * from 表 limit 199,100 db2: with t...

如果是sqlserver: where left(p.end_time,4) = '2012' 如果是Oracle: where substr(p.end_time,0,4) = '2012'

select * from shiyan003 a where exists (select 1 from (select xm, sfzhm from shiyan003 group by xm, sfzhm having count(*) > 1) s where s.xm = a.xm and s.sfzhm = a.sfzhm)

比如重复字段是 A 表 的 name 字段 select name from A group by name having count(name)>1 显示的就是 重复数 大于 1 的 name了 如果你要查看重复的数据 外面就加个 in name select * from A where name in( select name from A group by name...

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