重构查询函数中的硬编码值

Question

有人对如何更好地重构有什么建议吗？我已重命名项目名称以简化。

我只继承了这个（用于导入过程），它对我来说看起来不是很有效，尤其是函数中的硬编码值。我正在考虑将硬编码值放入 table 并引用它而不是函数，但我不确定如何根据查询中的重复列使其工作。

MyTable
    MyTableId INT,
    MyTableOtherColumn VARCHAR(100),
    MyTableDesc1 VARCHAR(10),
    MyTableDesc2 VARCHAR(10),
    . . .
    MyTable24 VARCHAR(10),
    MyTable25 VARCHAR(10),
    etc.

MyFunction
    RETURNS @myFunctionTable TABLE
    (
        myFunctionDesc VARCHAR(256),
        myFunctionCode VARCHAR(10)
    )
    AS 
    BEGIN
        INSERT INTO @myFunctionTable (myFunctionDesc, myFunctionCode) VALUES ('My Function Desc 1', 'MYCODE1');
        INSERT INTO @myFunctionTable (myFunctionDesc, myFunctionCode) VALUES ('My Function Desc 2', 'MYCODE2');
        . . .
        INSERT INTO @myFunctionTable (myFunctionDesc, myFunctionCode) VALUES ('My Function Desc 99', 'MYCODE99');
        INSERT INTO @myFunctionTable (myFunctionDesc, myFunctionCode) VALUES ('My Function Desc 100', 'MYCODE100');
    END


SELECT 
    MyTableId,
    MyTableOtherColumn,
    . . . 
    (SELECT myFunctionCode FROM MyFunction() WHERE MyFunctionDesc = MyTableDesc1),
    (SELECT myFunctionCode FROM MyFunction() WHERE MyFunctionDesc = MyTableDesc2),
    . . .
    (SELECT myFunctionCode FROM MyFunction() WHERE MyFunctionDesc = MyTableDesc24),
    (SELECT myFunctionCode FROM MyFunction() WHERE MyFunctionDesc = MyTableDesc25),
FROM myTable T
JOIN . . .
WHERE . . .

Answer 1

只需使用条件聚合和 outer apply:

SELECT MyTableId, MyTableOtherColumn,
       . . . 
       mf.val1, mv.val2, . . .
FROM myTable T JOIN
     . . . OUTER APPLY
     (SELECT MAX(CASE WHEN MyFunctionDesc = MyTableDesc1 THEN myFunctionCode END) as val1,
             MAX(CASE WHEN MyFunctionDesc = MyTableDesc2 THEN myFunctionCode END) as val2,
             . . .
      FROM MyFunction()
     ) mf
WHERE . . .

重构查询函数中的硬编码值

Refactor querying hardcoded values in function

sql

sql-server

refactoring

hardcoded