使用具有多个条件的sql获得总和

Question

我在列中的数据如下: -

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

现在按过程分组,我想要音量的总和(不考虑任何TAT),TAT =通过的音量总和,TAT =失败的音量总和.

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它们组合在一起,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不受支持,因此您可以使用SWITCH或IIF,如下所示:

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