SQL常用方法整理

去除字符串重复项：

declare @str varchar(8000)
declare @ret varchar(8000),@return varchar(8000)

select @str = 'APR-11,APR12,APR06,APR-11,APR12,APR06'

select @str = @str+','

while charindex(',',@str) > 0
begin
	select @ret = substring(@str,1,charindex(',',@str)-1)

	select @return = isnull(@return+',','')+@ret

	select @str = replace(@str,@ret+',','')
end 

select @return
---------------------------
APR-11,APR12,APR06