sql - 使用具有多个条件的sql获取总和

Question

我在列中有数据： -

  Process   Volume      TAT
  1            1        Pass
  1            2        Fail
  2            5        Fail
  2            5        Pass
  3            1        Pass
  4            6        Fail
  4            4        Pass

现在按进程分组，我想要体积总和（不考虑任何 TAT），TAT = 通过的体积总和，TAT = 失败的体积总和。

像这样

Process     Total Volume    Volume(TAT=Pass)    Volume(TAT = Fail)
1           3               1                   2
2           10              5                   5
...
...

Answer 1

对于 SQL Server，您可以使用CASE表达式有条件地确定需要添加的数量，然后将SUM它们放在一起，如下所示：

SELECT Process, SUM(Volume) AS TotalVolume, 
    SUM(CASE WHEN TAT = 'Pass' THEN Volume ELSE 0 END) AS Pass,
    SUM(CASE WHEN TAT = 'Fail' THEN Volume ELSE 0 END) AS Fail
FROM (
     -- Dummy data here for testing
    SELECT 1 AS Process, 1 as Volume, 'Pass' AS TAT
    UNION SELECT 1, 2, 'Fail'
    UNION SELECT 2, 5, 'Fail'
    UNION SELECT 2, 5, 'Pass'
    UNION SELECT 3, 1, 'Pass'
    UNION SELECT 4, 6, 'Fail'
    UNION SELECT 4, 4, 'Pass'
) MyTable
GROUP BY Process
ORDER BY Process

对于 Microsoft Access，CASE不支持，因此您可以使用SWITCHor IIF，如下所示：

SUM(IIF(TAT = 'Pass', Volume, 0)) AS Pass