カンマ区切り値の分割

以下に示すようなユーザー定義のUDFを作成できます。次に、別のクエリからカンマ区切りのリストを渡すだけで、各値が別々の行にあるテーブルが返されます。

CREATE FUNCTION [dbo].[fnSplitStringAsTable] 
(
    @inputString varchar(MAX),
    @delimiter char(1) = ','
)
RETURNS 
@Result TABLE 
(
    Value varchar(MAX)
)
AS
BEGIN
    DECLARE @chIndex int
    DECLARE @item varchar(100)

    -- While there are more delimiters...
    WHILE CHARINDEX(@delimiter, @inputString, 0) <> 0
        BEGIN
            -- Get the index of the first delimiter.
            SET @chIndex = CHARINDEX(@delimiter, @inputString, 0)

            -- Get all of the characters prior to the delimiter and insert the string into the table.
            SELECT @item = SUBSTRING(@inputString, 1, @chIndex - 1)

            IF LEN(@item) > 0
                BEGIN
                    INSERT INTO @Result(Value)
                    VALUES (@item)
                END

            -- Get the remainder of the string.
            SELECT @inputString = SUBSTRING(@inputString, @chIndex + 1, LEN(@inputString))
        END

    -- If there are still characters remaining in the string, insert them into the table.
    IF LEN(@inputString) > 0
        BEGIN
            INSERT INTO @Result(Value)
            VALUES (@inputString)
        END

    RETURN 
END