Question

I have been struggling with getting this query right for hours now. I have a huge amount of data and I want to show just the departments with IDs 10,15,18 and 25. From here, I want to subtract the profits for each dept with ID 18 from 15, i.e. 15-18.

I filter the data with the following query:

SELECT * FROM deptTable WHERE ID IN(10,15,18,25) AND date = ‘2009-01-25’

dept ———- date —————- ID —————– profit
UK ———- 2009-01-25 ———- 10 —————- 2000
Brazil ——- 2009-01-25 ———- 10 —————- 1300
Japan——- 2009-01-25 ——— 10 —————- 2500
Spain——- 2009-01-25 ———- 10 —————- 3200
UK ———- 2009-01-25 ———- 15 —————- 4000
Brazil ——- 2009-01-25 ———- 15 —————- 1700
Japan——- 2009-01-25 ———- 15 —————- 3500
Spain——– 2009-01-25 ———- 15 ————— 1200
UK ———- 2009-01-25 ———- 18 —————- 2500
Brazil ——- 2009-01-25 ———- 18 —————- 1300
Japan——- 2009-01-25 ——— 18 —————- 2120
Spain——- 2009-01-25 ———- 18 —————- 800
UK ———- 2009-01-25 ———- 25 —————- 3000
Brazil ——- 2009-01-25 ———- 25 —————- 1850
Japan——- 2009-01-25 ——— 25 —————- 1580
Spain——– 2009-01-25 ———- 25 ————— 1070

What I basically want is to then subtract each row with ID 18 from rows with ID 15. Taking the UK as an example:

4000 – 2500 = 1500, doing the rest of the dept regions will give the desired result which is:

dept ———- date —————- ID —————– profit
UK ———- 2009-01-25 ———- 10 —————- 2000
Brazil ——- 2009-01-25 ———- 10 —————- 1300
Japan——- 2009-01-25 ——— 10 —————– 2500
Spain——- 2009-01-25 ———- 10 —————- 3200
UK ———- 2009-01-25 ———- 15-18 ———— 1500
Brazil ——- 2009-01-25 ———- 15-18 ———— 400
Japan——- 2009-01-25 ———- 15-18 ———– 1380
Spain——– 2009-01-25 ———- 15-18 ———– 400
UK ———- 2009-01-25 ———- 25 —————- 3000
Brazil ——- 2009-01-25 ———- 25 —————- 1850
Japan——- 2009-01-25 ———- 25 —————- 1580
Spain——– 2009-01-25 ———- 25 ————— 1070

2 points:
1. The calculated rows ID column doesn’t have to read ’15-18′, I’ve just typed ’15-18′ to help explain the issue
2. The italics/bold are the only calculated rows, all other rows remain the same

Surely something like this is possible?

Thanks,

Answer 1

I think that something like this will work…

SELECT a.dept, a.date, IF(a.id=15,'15-18',a.id) AS id, IF(b.profit IS NULL,a.profit,a.profit-b.profit) AS profit
FROM deptTable a 
LEFT JOIN deptTable b ON a.ID=15 AND b.ID=18 AND a.dept=b.dept
WHERE a.ID IN(10,15,25) AND a.date = '2009-01-25' 

Tested result:

+--------+------------+-------+--------+
| dept   | date       | id    | profit |
+--------+------------+-------+--------+
| UK     | 2009-01-25 | 10    |   2000 |
| Brazil | 2009-01-25 | 10    |   1300 |
| JAPAN  | 2009-01-25 | 10    |   2500 |
| SPAIN  | 2009-01-25 | 10    |   3200 |
| UK     | 2009-01-25 | 15-18 |   1500 |
| Brazil | 2009-01-25 | 15-18 |    400 |
| JAPAN  | 2009-01-25 | 15-18 |   1380 |
| SPAIN  | 2009-01-25 | 15-18 |    400 |
| UK     | 2009-01-25 | 25    |   3000 |
| Brazil | 2009-01-25 | 25    |   1850 |
| JAPAN  | 2009-01-25 | 25    |   1580 |
| SPAIN  | 2009-01-25 | 25    |   1070 |
+--------+------------+-------+--------+