sqlserver 从数据源左侧截取到遇到特殊字符的最短的子字符串

select dbo.sjGetPreStr('1234^5*6/-33_','[]-_=+*&^')       ===> 1234

Create function [dbo].[sjGetPreStr](@str varchar(1000),@pointArr varchar(100))
returns varchar(1000)
as
begin
    declare @res varchar(1000) = ''
    declare @i int = 1
    declare @c varchar(4) = ''
    declare @j int = 0
    declare @min varchar(1000) = ''
    declare @temp varchar(1000) = ''
    set @str = rtrim(ltrim(@str))
    set @pointArr = rtrim(ltrim(@pointArr))
    set @min = @str
    if len(@str) = 0 or len(@pointArr) = 0
    begin
        set @res = 'Parameters cannot be empty'
    end
    else
    begin
        while @i <= len(@pointArr)
        begin
            set @c = substring(@pointArr,@i,1)
            set @j = charindex(@c,@str)
            if @j > 0
            begin
                set @temp = substring(@str,1,@j - 1)
                if len(@temp) < len(@min)
                begin
                    set @min = @temp
                end
            end
            set @i = @i + 1
            set @j = 0
        end
        set @res = @min
    end
    return @res
end