SQL 删除表中的重复记录，只保留其中一条。

方法一

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

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
)
)

方法二

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