几个实用的SQL语句

原创
2013/07/03 00:57
阅读数 34
在对数据进行分析处理时,有时候会遇到要处理重复记录的问题,下面分享下针对重复记录的几个SQL语法。
http://www.powerbibbs.com/thread-184-1-1.html

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 peopleId in (select   peopleId from people group by   peopleId   having count 
(peopleId) > 1) 
and rowid not in (select min(rowid) from   people group by peopleId having count(peopleId 
)>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) 
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