Re: cross tab (pivtor table) sql - Mailing list pgsql-sql

From Michael Paesold
Subject Re: cross tab (pivtor table) sql
Date
Msg-id 012201c25d89$1fc67e00$4201a8c0@beeblebrox
Whole thread Raw
In response to cross tab (pivtor table) sql  (chaudhar@umich.edu (shahbaz))
List pgsql-sql
shahbaz wrote:

> 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).

I am not sure if this is what you want, but I'll try. So to get
a row for each second with all stocks (that need to be know at the
time of writing the query), I would try this (not tested, could
be quite slow):

SELECT DISTINCT ON (time) time, (SELECT MAX(price) FROM stocks b WHERE b.time=a.time AND b.stock='PSQL')
AS PSQL, (SELECT MAX(price) FROM stocks b WHERE b.time=a.time AND b.stock='MSFT')
AS MSFT, (SELECT MAX(price) FROM stocks b WHERE b.time=a.time AND b.stock='ORCL')
AS ORCL FROM stocks a ORDER BY time;

Let me know if it works...

Regards, Michael Paesold



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