Sql Server中常用的6个自定义函数分享

转自:http://www.jb51.net/article/56691.htm

 IF OBJECT_ID('DBO.DISTINCT_STR') IS NOT NULL
 DROP FUNCTION DBO.DISTINCT_STR
 GO
 --此函数操作形如["a", "b", 1,2,3,1,"a"]的数组,去重后,["b",1,2,3]
 --@S(原有参数), @SPLIT(分隔符), @NEW_STR(新添加字符串)
 CREATE FUNCTION DISTINCT_STR(@S NVARCHAR(300),@SPLIT VARCHAR(50),@NEW_STR VARCHAR(300))
 RETURNS VARCHAR(300)
 AS
 BEGIN
 DECLARE @NEW VARCHAR(200),@INDEX INT,@TEMP VARCHAR(200)
 
 IF CHARINDEX(']',@S)>0 and CHARINDEX(']', @S) > 0
 SET @S=SUBSTRING(@S,charindex('[',@S)+1,LEN(@S)-2) + @SPLIT + @NEW_STR
 ELSE
 SET @S=@NEW_STR
 
 IF LEFT(@S,1)<>@SPLIT
 SET @S = @SPLIT+@S
 IF RIGHT(@S,1)<>@SPLIT
 SET @S = @S+@SPLIT
 WHILE CHARINDEX(@SPLIT,@S)>0 AND LEN(@S)<>1
 BEGIN
 SET @INDEX = CHARINDEX(@SPLIT,@S)
 SET @TEMP = LEFT(@S,CHARINDEX(@SPLIT,@S,@INDEX+LEN(@SPLIT)))
 IF @NEW IS NULL
 SET @NEW = ISNULL(@NEW,'')+@TEMP
 ELSE
 SET @NEW = ISNULL(@NEW,'')+REPLACE(@TEMP,@SPLIT,'')+@SPLIT
 WHILE CHARINDEX(@TEMP,@S)>0
 BEGIN
 SET @S=STUFF(@S,CHARINDEX(@TEMP,@S)+LEN(@SPLIT),CHARINDEX(@SPLIT,@S,CHARINDEX(@TEMP,@S)+LEN(@SPLIT))-CHARINDEX(@TEMP,@S),'')
 END
 END
 RETURN '['+RIGHT(LEFT(@NEW,LEN(@NEW)-1),LEN(LEFT(@NEW,LEN(@NEW)-1))-1)+']'
 END
 GO