Question

我在下面有以下查询。如何获得第1列和第3列的总和？和＆＃39;第2列＆＃39;？ X和Y只是样本数据，使问题更容易理解。

int randomNumber;

randomNumber = new Random().Next(1, n + 1);

switch(randomNumber)
{
   case 1: ShowPage1();
           break;
   case 2: ShowPage2();
           break;
   case 3: ShowPage3();
           break;
   ...
   case n: ShowPageN();
             break;
}

Answer 1

如果您希望第1列+第2列的结果用于table1中的每一行，您可以使用此查询：

SELECT [Column 1] + [Column 2]
FROM (
    SELECT  
        CASE
            WHEN x = 0 then 2
            WHEN x = 1 then 4
            ELSE 6
        END AS [Column 1]
        , CASE
            WHEN y = 0 THEN 3
            WHEN y = 1 THEN 6
            ELSE 9
        END AS [Column 2]
    FROM table1
) AS IntermediateResult

如果您想要第1列中所有值的总和以及第2列中的所有值，则可以使用第1列和第2列。

SELECT SUM([Column 1] + [Column 2])
FROM (
    SELECT  
        CASE
            WHEN x = 0 then 2
            WHEN x = 1 then 4
            ELSE 6
        END AS [Column 1]
        , CASE
            WHEN y = 0 THEN 3
            WHEN y = 1 THEN 6
            ELSE 9
        END AS [Column 2]
    FROM table1
) AS IntermediateResult

Answer 2

尝试：

SELECT 
    SUM
    (
        CASE x
            WHEN 0 THEN 2
            WHEN 1 THEN 4
            ELSE 6
        END
    ) AS [Column 1],

    SUM
    (
        CASE y
            WHEN 0 THEN 3
            WHEN 1 THEN 6
            ELSE 9
        END
    ) AS [Column 2]
FROM
    table1

SUM 两列

SELECT 
    (
        CASE x
            WHEN 0 THEN 2
            WHEN 1 THEN 4
            ELSE 6
        END
    )
    +
    (
        CASE y
            WHEN 0 THEN 3
            WHEN 1 THEN 6
            ELSE 9
        END
    ) AS [Column 1]
FROM
    table1

如何SUM同一行中的多个列

2 个答案: