方法一

第一步：查询重复记录

SELECT * FROM TableName  --表名WHERE RepeatFiled IN (      SELECT RepeatFiled  --重复字段    FROM TableName      GROUP BY RepeatFiled      HAVING COUNT(RepeatFiled) > 1  )

把重复条数大于1的全部查询出来。

第二步：删除重复记录，只保留一条

SELECT * FROM TableName  WHERE RepeatFiled IN (      SELECT RepeatFiled      FROM TableName      GROUP BY RepeatFiled      HAVING COUNT(RepeatFiled) > 1      AND      ID NOT IN (          SELECT MIN(ID)          FROM TableName          GROUP RepeatFiled          HAVING COUNT(RepeatFiled) > 1          )  )

在第一步的基础上继续过滤，把最小值留下。

方法二

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