Question

我一直在尝试编写一个Table-Valued函数，它将值对作为参数并返回一个包含两列的表。

以下是我正在尝试的功能签名。

FUNCTION [dbo].[ValuePairParser]( @DelimitedValuePairs VARCHAR(MAX),
                                  @Delimiter CHAR(1), 
                                  @ValuePairDelimiter CHAR(1) ) 
  RETURNS @ValuePairTable
  TABLE ( Id INT, Code INT )

我想调用下面的方法

@ValuePairs VARCHAR(MAX) = '1:1, 1:2, 1:4, 2:3, 1000:230, 130:120,'

ValuePairParser (@ValuePairs, ',', ':')

你能看到在ValuePairs sting之上拆分并创建一个包含两列的表的好方法吗？

Answer 1

CREATE FUNCTION [dbo].[SplitWithPairs]
(
    @List NVARCHAR(MAX),
    @MajorDelimiter VARCHAR(3) = ',',
    @MinorDelimiter VARCHAR(3) = ':'
)
RETURNS @Items TABLE
(
    Position  INT IDENTITY(1,1) NOT NULL,
    LeftItem  INT NOT NULL,
    RightItem INT NOT NULL
)
AS
BEGIN
    DECLARE
        @Item      NVARCHAR(MAX),
        @LeftItem  NVARCHAR(MAX),
        @RightItem NVARCHAR(MAX),
        @Pos       INT;

    SELECT
        @List = @List + ' ',
        @MajorDelimiter = LTRIM(RTRIM(@MajorDelimiter)),
        @MinorDelimiter = LTRIM(RTRIM(@MinorDelimiter));

    WHILE LEN(@List) > 0
    BEGIN
        SET @Pos = CHARINDEX(@MajorDelimiter, @List);

        IF @Pos = 0 
            SET @Pos = LEN(@List) + LEN(@MajorDelimiter);

        SELECT
            @Item = LTRIM(RTRIM(LEFT(@List, @Pos - 1))),
            @LeftItem = LTRIM(RTRIM(LEFT(@Item,
            CHARINDEX(@MinorDelimiter, @Item) - 1))),
            @RightItem = LTRIM(RTRIM(SUBSTRING(@Item,
            CHARINDEX(@MinorDelimiter, @Item)
            + LEN(@MinorDelimiter), LEN(@Item))));

        INSERT @Items(LeftItem, RightItem)
            SELECT @LeftItem, @RightItem;

        SET @List = SUBSTRING(@List,
            @Pos + LEN(@MajorDelimiter), DATALENGTH(@List));
    END
    RETURN;
END
GO

DECLARE @ValuePairs VARCHAR(MAX) = '1:1, 1:2, 1:4, 2:3,1000:230, 130:120,';

SELECT LeftItem, RightItem
  FROM dbo.SplitWithPairs(@ValuePairs, ',', ':')
  ORDER BY Position;
GO

Answer 2

create function ValuePairParser(@DelimitedValuePairs varchar(MAX),
                                @Delimiter char(1), 
                                @ValuePairDelimiter char(1)) 
returns @ValuePairTable table(Id int, Code int) as
begin 
  with Split(ValuePair, Rest) as
  (
    select left(@DelimitedValuePairs, charindex(@Delimiter, @DelimitedValuePairs)-1),
           stuff(@DelimitedValuePairs, 1, charindex(@Delimiter, @DelimitedValuePairs), '')
    where charindex(@Delimiter, @DelimitedValuePairs) > 0
    union all
    select left(Rest, charindex(@Delimiter, Rest)-1),
           stuff(Rest, 1, charindex(@Delimiter, Rest), '')
    from Split         
    where charindex(@Delimiter, Rest) > 0
  )               
  insert into @ValuePairTable
  select left(ValuePair, charindex(@ValuePairDelimiter, ValuePair)-1),
         stuff(ValuePair, 1, charindex(@ValuePairDelimiter, ValuePair), '')
  from Split                 
  option (maxrecursion 0)

  return
end

使用UDF拆分值对和创建表

2 个答案: