20181123_SQL Server 2008_找出以逗号分隔的字符串中最大的数字

 --select    [dbo].[Fun_GetMaxNum]('棉 20%,麻 190%,涤纶60%')
 CREATE     FUNCTION [dbo].[Fun_GetMaxNum] ( @StrAll NVARCHAR(MAX))
 RETURNS int
 AS
 BEGIN   --棉 50%,麻 40%,涤纶60%
      DECLARE @currentStr NVARCHAR(512) , --当前的字符串
      @backStr NVARCHAR(512), @max INT, @index INT ,@flag INT  --只准一次
      SET  @index=0
      SET  @max=0
      SET  @flag=1
      WHILE  ( CHARINDEX (',',@StrAll)>=0  and  @flag=1 ) --如果字符串中没有逗号, 使用 PATINDEX 函数, 支持正则
         BEGIN
             IF  (CHARINDEX(',',@StrAll) = 0 ) BEGIN   SET  @flag=0 END
             IF  (CHARINDEX (',',@StrAll) > 0)
                 BEGIN
                     SET  @index=CHARINDEX (',',@StrAll)
                 END
             ELSE
                 BEGIN
                     SET  @index=0
                 END
             SET  @currentStr= CASE  @index WHEN  0 THEN  @StrAll ELSE  (LEFT(@StrAll ,@index-1)) END
             SET  @StrAll = (SELECT  SUBSTRING(@StrAll,CHARINDEX (',',@StrAll) +1,LEN (@StrAll)))
              BEGIN
                 WHILE PATINDEX('%[^0-9]%',@currentStr)>0
                     BEGIN
                         SET @currentStr=STUFF(@currentStr,PATINDEX('%[^0-9]%',@currentStr),1,'') --删掉非数字的字符
                     END
                 IF  CAST(@currentStr AS  INT  ) > @max
                     BEGIN
                         SET     @max = cast(@currentStr AS  INT )
                     END
             END
         END
     RETURN @Max
 END

执行结果: