感謝孫瀟楠前輩的總結，地址http://www.cnblogs.com/sunxiaonan/archive/2009/11/24/1609439.html

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是主鍵 要求得到這樣的結果 id name value 1 a pp 3 b iii 4 b pp 6 c pp 8 c iii

方法1delete YourTable where [id] not in ( select max([id]) from YourTable group by (name + value)) 方法2delete a from 表 a left join( select id=min(id) from 表 group by name,value )b on a.id=b.id where b.id is null 查詢及刪除重復記錄的SQL語句1、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 peoplewhere 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 peoplewhere 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 awhere (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 awhere (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 awhere (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)(二)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

(三)方法一declare @max integer,@id integerdeclare cur_rows cursor local for select 主字段,count(*) from 表名 group by 主字段 having count(*) >； 1open cur_rowsfetch cur_rows into @id,@maxwhile @@fetch_status=0beginselect @max = @max -1set rowcount @maxdelete from 表名 where 主字段 = @idfetch cur_rows into @id,@maxendclose cur_rowsset rowcount 0

方法二＂重復記錄＂有兩個意義上的重復記錄，一是完全重復的記錄，也即所有字段均重復的記錄，二是部分關鍵字段重復的記錄，比如Name字段重復，而其他字段不一定重復或都重復可以忽略。　　1、對于第一種重復，比較容易解決，使用select distinct * from tableName　　就可以得到無重復記錄的結果集。　　如果該表需要刪除重復的記錄（重復記錄保留1條），可以按以下方法刪除select distinct * into #Tmp from tableNamedrop table tableNameselect * into tableName from #Tmpdrop table #Tmp　　發生這種重復的原因是表設計不周產生的，增加唯一索引列即可解決?！　?、這類重復問題通常要求保留重復記錄中的第一條記錄，操作方法如下　　假設有重復的字段為Name,Address，要求得到這兩個字段唯一的結果集select identity(int,1,1) as autoID, * into #Tmp from tableNameselect min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoIDselect * from #Tmp where autoID in(select autoID from #tmp2)　　最后一個select即得到了Name，Address不重復的結果集（但多了一個autoID字段，實際寫時可以寫在select子句中省去此列）(四)查詢重復select * from tablename where id in (select id from tablenamegroup by idhaving count(id) > 1)