資料庫查詢結果動態排序（五）：使用者定義函數 (UDF) 實作、TOP 100 PERCENT 技巧與函數調用方式

CREATE FUNCTION ufn_GetSortedShippers(@ColName AS SYSNAME)
RETURNS TABLE
AS
RETURN
SELECT *
FROM Shippers
ORDER BY
    CASE @ColName
        WHEN 'ShipperID' THEN ... -- 字串化邏輯
        WHEN 'CompanyName' THEN CompanyName
        WHEN 'Phone' THEN Phone
        ELSE NULL
    END

CREATE FUNCTION ufn_GetSortedShippers(@ColName AS SYSNAME)
RETURNS TABLE
AS
RETURN
SELECT TOP 100 PERCENT *
FROM Shippers
ORDER BY
    CASE @ColName
        WHEN 'ShipperID' THEN ... 
        WHEN 'CompanyName' THEN CompanyName
        WHEN 'Phone' THEN Phone
        ELSE NULL
    END