如何通过多列来区分

Question

我正在努力实现这个目标

VM  Disk    Capacity
VM1 Disk 1  100
VM1 Disk 2  40
VM1 Disk 1  100
VM1 Disk 2  40
VM2 Disk 1  45
VM2 Disk 1  45
VM3 Disk 1  30
VM3 Disk 2  30

结果应该是这样的

VM    Capacity
VM1    140
VM2    45
VM3    60

Answer 1

这有帮助吗？

SELECT a.column1, SUM(column3) FROM
(
SELECT DISTINCT column1, column2, column3 FROM tableA
) a 
GROUP BY column1

Answer 2

你去吧

http://sqlfiddle.com/#!6/285fe

SELECT a.vm, SUM(capacity)
FROM (
SELECT DISTINCT vm, DISK, capacity
FROM TEMP
) a
GROUP BY vm

Answer 3

SELECT a.vm, SUM(capacity) as capacity FROM
  (
SELECT DISTINCT vm, disk, capacity FROM test
  ) a 
GROUP BY vm

SQL fiddle