MSSQL移除字符串两边的指定字符

CREATE FUNCTION [dbo].[RemoveLeftChar] 
(
    @Expression varchar(max),
    @char varchar(4)
)
RETURNS varchar(max)
AS
BEGIN
    WHILE LEN(@Expression)>0 AND CHARINDEX(@char,@Expression)=1
    BEGIN
        SET @Expression=SUBSTRING(@Expression,LEN(@char)+1,LEN(@Expression))
    END
    return @Expression
END

CREATE FUNCTION [dbo].[RemoveRightChar] 
(
    @Expression varchar(max),
    @char varchar(4)
)
RETURNS varchar(max)
AS
BEGIN
    DECLARE @Len int
    SET @Len=LEN(@Expression)
    WHILE @Len>0 AND SUBSTRING(@Expression,@Len-len(@char)+1,@Len)=@char
    BEGIN
        SET @Expression=SUBSTRING(@Expression,1,@Len-LEN(@char))
        SET @Len=LEN(@Expression)
    END
    return @Expression
END

SELECT [dbo].[RemoveLeftChar](‘|123|234|345|‘,‘|‘)

--输出结果
123|234|345|

SELECT [dbo].[RemoveLeftChar](‘|||123|234|345|‘,‘|‘)

--输出结果
123|234|345|

SELECT [dbo].[RemoveRightChar](‘|123|234|345|‘,‘|‘)

--输出结果
|123|234|345

SELECT [dbo].[RemoveRightChar](‘|123|234|345|||‘,‘|‘)

--输出结果
|123|234|345

SELECT [dbo].[RemoveLeftChar]([dbo].[RemoveRightChar](‘|123|234|345|‘,‘|‘),‘|‘)

--输出结果
123|234|345