使用SQL在多个条件下求和

Question

I m having data in columns as: -

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

Now grouping by Process, i want the sum of volume (not taking into account whatever TAT), sum of volume where TAT = Pass, sum of Volume where TAT = Fail.

Like this

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

Answer 1

For SQL Server, you can use CASE expressions to conditionally determine the amount you need to add, then SUM them together, like this:

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

For Microsoft Access, CASE isn't supported, so you can use SWITCH or IIF , like so:

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