查詢及刪除重復(fù)記錄的SQL語句 1、查找表中多余的重復(fù)記錄，重復(fù)記錄是根據(jù)單個字段（Id）來判斷 select * from 表 where Id in (select Id from 表 group by Id having count(Id) > 1)
2、刪除表中多余的重復(fù)記錄，重復(fù)記錄是根據(jù)單個字段（Id）來判斷，只留有rowid最小的記錄 DELETE from 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY id HAVING COUNT(*) > 1);
3、查找表中多余的重復(fù)記錄（多個字段） select * from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) 4、刪除表中多余的重復(fù)記錄（多個字段），只留有rowid最小的記錄 delete from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1) 5、查找表中多余的重復(fù)記錄（多個字段），不包含rowid最小的記錄 select * from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,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(xiàn)在就是需要查詢出在該表中的各記錄之間，“name”值存在重復(fù)的項(xiàng)； 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
復(fù)制代碼 代碼如下:
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(*) >； 1 open cur_rows fetch cur_rows into @id,@max while @@fetch_status=0 begin select @max = @max -1 set rowcount @max delete from 表名 where 主字段 = @id fetch cur_rows into @id,@max end close cur_rows
set rowcount 0 方法二 ＂重復(fù)記錄＂有兩個意義上的重復(fù)記錄，一是完全重復(fù)的記錄，也即所有字段均重復(fù)的記錄，二是部分關(guān)鍵字段重復(fù)的記錄，比如Name字段重復(fù)，而其他字段不一定重復(fù)或都重復(fù)可以忽略。 1、對于第一種重復(fù)，比較容易解決，使用 select distinct * from tableName 就可以得到無重復(fù)記錄的結(jié)果集。 如果該表需要刪除重復(fù)的記錄（重復(fù)記錄保留1條），可以按以下方法刪除
復(fù)制代碼 代碼如下:
select distinct * into #Tmp from tableName drop table tableName select * into tableName from #Tmp drop table #Tmp
select identity(int,1,1) as autoID, * into #Tmp from tableName select min(autoID) as autoID into #Tmp2 from #Tmp group by Name,autoID select * from #Tmp where autoID in(select autoID from #tmp2)
