Hi all, I wonder if someone can help me write a sql query for the
following scenario:
I have a table that looks like the fillowing:
[time] [stock] [price]
11111 MSFT 1
11112 ORCL 2
11112 SUNW 3
11112 SUNW 2
11113 ORCL 5
11114 MSFT 4
11115 ORCL 3
etc.
I need to convert the above table to the following:
[time] [MSFT] [ORCL] [SUNW] ...
11111 1 3 1
11112 2 3 3 <-------|
11113 3 4 2 <-------|----these values are prices
11114 5 2 3 <-------|
11115 4 1 8
(obviously, don't pay any attention to the actual numbers I used).
Essentially I want to pivot my table (like in Excel or OLAP tools).
I can't use excel because I have too much data...I'd like to take care
of this in a database any way.
I tried the following using postgresql:
select time,
CASE WHEN stock='A' THEN max(price) ELSE sum(0) END AS A,
CASE WHEN stock='AA' THEN max(price) ELSE sum(0) END AS AA,
CASE WHEN stock='AACB' THEN max(price) ELSE sum(0) END AS AACB,
CASE WHEN stock='AAGI' THEN max(price) ELSE sum(0) END AS AAGI
...
from mytable
group by time, stock
(notice I had to use max(price) because there me be more than one
price update during a second).
Unfortunately this doesn't work, it just returns a bunch of zeroes.
It seems to me that there has to be a way of doing this without
resorting to expensive olap tools. Any ideas will be appreciated,
thanks.
