原文:08. 删除重复&海量数据 重复数据,通常有两种:一是完全重复的记录,也就是所有字段的值都一样:二是部分字段值重复的记录. 一. 删除完全重复的记录完全重复的数据,通常是由于没有设置主键/唯一键约束导致的.测试数据: if OBJECT_ID('duplicate_all') is not null drop table duplicate_all GO create table duplicate_all ( c1 int, c2 int, c3 ) ) GO insert into d…
08. 删除重复&海量数据 重复数据,通常有两种:一是完全重复的记录,也就是所有字段的值都一样:二是部分字段值重复的记录. 一. 删除完全重复的记录完全重复的数据,通常是由于没有设置主键/唯一键约束导致的.测试数据: if OBJECT_ID('duplicate_all') is not null drop table duplicate_all GO create table duplicate_all ( c1 int, c2 int, c3 varchar(100) ) GO ins…
例如: id name value 1 a pp 2 a pp 3 b iii 4 b pp 5 b pp 6 c pp 7 c pp 8 c iii id是主键 要求得到这样的结果 id name value 1 a pp 3 b iii 4 b pp 6 c pp 8 c iii 方法1 delete YourTable where [id] not in ( select max([id]) from YourTable group by (name + value)) 方法2 delet…
Write a SQL query to delete all duplicate email entries in a table named Person, keeping only unique emails based on its smallest Id. +----+------------------+ | Id | Email | +----+------------------+ | 1 | john@example.com | | 2 | bob@example.com |…
查询及删除重复记录的SQL语句 1.查找表中多余的重复记录,重复记录是根据单个字段(Id)来判断 select * from 表 where Id in (select Id from 表 group byId having count(Id) > 1) 2.删除表中多余的重复记录,重复记录是根据单个字段(Id)来判断,只留有rowid最小的记录 DELETE from 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING C…
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 Server删除重复行是我们最常见的操作之一,下面就为您介绍六种适合不同情况的SQL Server删除重复行的方法,供您参考. 1.如果有ID字段,就是具有唯一性的字段 delect table tableName where id not in ( select max(id) from table group by col1,col2,col3... ) group by 子句后跟的字段就是你用来判断重复的条件,如…
delete from co_jobinformation cwhere c.name in (select cc.name from co_jobinformation cc group by cc.name having count(cc.name) > 1)and rowid not in (select min(rowid) from co_jobinformation e group by e.name having count(e.name )>1) 之前在oracle数…
