--創建測試表
if object_id('test') is not null
drop table test
create table test
(
id int identity(1,1) primary key,
name varchar(50)
)
--插入幾條測試數據
insert into test select 'a' union all
select 'a' union all
select 'a' union all
select 'a' union all
select 'a' union all
select 'a' union all
select 'b' union all
select 'b' union all
select 'b' union all
select 'b' union all
select 'b' union all
select 'b' union all
select 'b' union all
select 'c' union all
select 'c' union all
select 'c' union all
select 'd' union all
select 'd'
--查看當前記錄
select * from test
if object_id('#') is not null
drop table #
--注意(是單個字段的不同還是多個字段,這里是name)
select distinct (name) into # from test
--查看新表中的數據
select from #
--清空舊表
truncate table test
--將新表中的數據插入到舊表
insert test select from #
--刪除新表
drop table #
--查看結果
select from test</pre>
查找表中多余的重復記錄，重復記錄是根據單個字段（peopleId）來判斷
select from people
where peopleId in (select peopleId from people group by peopleId having count(peopleId) > 1)
2、刪除表中多余的重復記錄，重復記錄是根據單個字段（peopleId）來判斷，只留有rowid最小的記錄
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、查找表中多余的重復記錄（多個字段）
select from vitae a
where (a.peopleId,a.seq) in (select peopleId,seq from vitae group by peopleId,seq having count() > 1)
4、刪除表中多余的重復記錄（多個字段），只留有rowid最小的記錄
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、查找表中多余的重復記錄（多個字段），不包含rowid最小的記錄
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)
比方說在A表中存在一個字段“name”，而且不同記錄之間的“name”值有可能會相同，
現在就是需要查詢出在該表中的各記錄之間，“name”值存在重復的項；
Select Name,Count() From A Group By Name Having Count() > 1
如果還查性別也相同大則如下:
Select Name,sex,Count() From A Group By Name,sex Having Count(*) > 1
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