使用带有多个条件的sql获取sum

Question

我在列中有这样的数据：

  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，我想要卷的和(不考虑任何TAT)，TAT =通过的卷的和，TAT =失败的卷的和。

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，然后将它们SUM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，不支持CASE，因此您可以使用SWITCH或IIF，如下所示：

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