如何通過多發柱

Question

我竭力要實現這一

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 

結果應該是這樣的

VM Capacity 
VM1 140 
VM2 45 
VM3 60 

Answer 1

這是否幫助總結不同？

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

Answer 2

在這裏你去

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