PadLeft 和 PadRight

1 PadLeft

即：向已知字符串左边补充字符，使整个字符串到达指定长度

 CREATE FUNCTION PadLeft
 (
     @VarOrgan varchar(10),/*原始字符*/
     @TotalLength int,/*总长度*/
     @Placeholder varchar(1)/*占位符*/
 )
 RETURNS varchar(100)
 AS
 BEGIN
     declare @VarNew varchar(100),
             @PadLen int
     SET @VarNew=@VarOrgan
     SET @PadLen=@TotalLength-LEN(@VarOrgan)
     while(@PadLen>0)
         begin
             select @VarNew=@Placeholder+@VarNew
             set @PadLen=@PadLen-1
         end
     return @VarNew
 END

2 PadRight

即：向已知字符串右边补充字符，使整个字符串到达指定长度

 CREATE FUNCTION PadRight
 (
     @VarOrgan varchar(10),/*原始字符*/
     @TotalLength int,/*总长度*/
     @Placeholder varchar(1)/*占位符*/
 )
 RETURNS varchar(100)
 AS
 BEGIN
     declare @VarNew varchar(100),
             @PadLen int
     SET @VarNew=@VarOrgan
     SET @PadLen=@TotalLength-LEN(@VarOrgan)
     while(@PadLen>0)
         begin
             select @VarNew=@VarNew+@Placeholder
             set @PadLen=@PadLen-1
         end
     return @VarNew
 END

3 测试结果

SELECT dbo.PadLeft('',6,'') PadLeft,
        dbo.PadRight('',4,'') PadRight