数据库自定义表值函数Split(@LongStr, @SplitStr, @IsDistinct )

CREATE FUNCTION [dbo].[F3_Split](@LongStr VARCHAR(MAX),@SplitStr VARCHAR(100),@IsDistinct BIT)
RETURNS @RTable TABLE(ID INT IDENTITY PRIMARY KEY,ShortStr VARCHAR(MAX))
AS BEGIN
IF ISNULL(@LongStr,'')='' --表达式为空或NULL直接返回空表
RETURN
IF ISNULL(@SplitStr,'')='' --分隔符为空直接返回一条记录的表（存放表达式）
BEGIN
INSERT INTO @RTable(ShortStr) SELECT @LongStr
RETURN
END
DECLARE @Split_len INT
DECLARE @LongStr_len INT
SET @Split_len=LEN(@SplitStr) --分隔符的长度
SET @LongStr_len=LEN(@LongStr) --目前表达式的长度
WHILE CHARINDEX(@SplitStr,@LongStr)>0
BEGIN
DECLARE @ShortStr VARCHAR(1000) --分割后的字符串
SET @ShortStr=SUBSTRING(@LongStr,1,CHARINDEX(@SplitStr,@LongStr)-1) --每次从第1个位置开始取分隔符所在的位置-1为一截
SET @LongStr=SUBSTRING(@LongStr,CHARINDEX(@SplitStr,@LongStr)+@Split_len,(@LongStr_len-LEN(@ShortStr)-@Split_len)) --变换表达式的值为剩下的
SET @LongStr_len=LEN(@LongStr) --变换表达式的长度
IF @ShortStr<>'' AND @IsDistinct=1
INSERT INTO @RTable(ShortStr) SELECT @ShortStr
WHERE NOT EXISTS(SELECT 1 FROM @RTable WHERE ShortStr=@ShortStr) --将分割出来的字符串放入表中
ELSE IF @ShortStr<>''
INSERT INTO @RTable(ShortStr) SELECT @ShortStr
END
IF @LongStr<>'' AND @IsDistinct=1 --如果最后一截没有分隔符，则直接进入表中
INSERT INTO @RTable(ShortStr) SELECT @LongStr
WHERE NOT EXISTS(SELECT 1 FROM @RTable WHERE ShortStr=@LongStr)
ELSE IF @LongStr<>''
INSERT INTO @RTable(ShortStr) SELECT @LongStr
RETURN
END