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(一)
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) > )
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) > )
and rowid not in (select min(rowid) from people group by peopleId having count(peopleId )>)
查找表中多余的重复记录（多个字段）
select * from vitae a
where (apeopleIdaseq) in (select peopleIdseq from vitae group by peopleIdseq having count(*) > )
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 (apeopleIdaseq) in (select peopleIdseq from vitae group by peopleIdseq having count(*) > )
and rowid not in (select min(rowid) from vitae group by peopleIdseq having count(*)>) 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 (apeopleIdaseq) in (select peopleIdseq from vitae group by peopleIdseq having count(*) > )
and rowid not in (select min(rowid) from vitae group by peopleIdseq having count(*)>)
(二)
比方说
在A表中存在一个字段“name”
而且不同记录之间的“name”值有可能会相同
现在就是需要查询出在该表中的各记录之间“name”值存在重复的项
Select NameCount(*) From A Group By Name Having Count(*) >
如果还查性别也相同大则如下:
Select Name*Count(*) From A Group By Name* Having Count(*) > (三)
方法一
declare @max integer@id integer
declare cur_rows cursor local for select 主字段count(*) from 表名 group by 主字段 having count(*) >
open cur_rows
fetch cur_rows into @id@max
while @@fetch_status=
begin
select @max = @max
set rowcount @max
delete from 表名 where 主字段 = @id
fetch cur_rows into @id@max
end
close cur_rows
set rowcount
方法二
有两个意义上的重复记录一是完全重复的记录也即所有字段均重复的记录二是部分关键字段重复的记录比如Name字段重复而其他字段不一定重复或都重复可以忽略
对于第一种重复比较容易解决使用
select distinct * from tableName
就可以得到无重复记录的结果集
如果该表需要删除重复的记录（重复记录保留条）可以按以下方法删除
select distinct * into #Tmp from tableName
drop table tableName
select * into tableName from #Tmp
drop table #Tmp
发生这种重复的原因是表设计不周产生的增加唯一索引列即可解决
这类重复问题通常要求保留重复记录中的第一条记录操作方法如下
假设有重复的字段为NameAddress要求得到这两个字段唯一的结果集
select identity(int) as autoID * into #Tmp from tableName
select min(autoID) as autoID into #Tmp from #Tmp group by NameautoID
select * from #Tmp where autoID in(select autoID from #tmp)
最后一个select即得到了NameAddress不重复的结果集（但多了一个autoID字段实际写时可以写在select子句中省去此列）
(四)
查询重复
select * from tablename where id in (
select id from tablename
group by id
having count(id) >
)
查找表中多余的重复记录（多个字段）
select * from vitae a
where (apeopleIdaseq) in (select peopleIdseq from vitae group by peopleIdseq having count(*) > )
运行会产生问题where(apeopleIdaseq)这样的写发是通不过的！！！ |
