On 06/11/2012 06:53 AM, Igor Neyman wrote:
-----Original Message-----
From: John Fabiani [mailto:jo...@jfcomputer.com]
Sent: Thursday, June 07, 2012 7:18 PM
To: pgsql-sql@postgresql.org
Subject: using ordinal_position
I'm attempting to retrieve data using a select statement without
knowing the column names. I know the ordinal position but not the name
of the column (happens to be a date::text and I have 13 fields).
Below provides the name of the column in position 3:
select column_name from (select column_name::text, ordinal_position
from information_schema.columns where
table_name='wk_test') as foo where ordinal_position = 3;
But how can I use the above as a column name in a normal select
statement.
Unlike other databases I just can't use ordinal position in the select
statement - RIGHT???
Johnf
David gave you already pretty complete answer.
I just wonder what are these "other" RDBMSs that allow to use ordinal column
positions in a query?
I am familiar with a few (in addition to Postgress), and none of them does that, not in "select" list.,
though everybody allow ordinal position from "select" list in "order by" and "group by".
Regards,
Igor Neyman
VFP uses position (you might not consider DBF a database). MsSQl
(ordinal_position). Those are the only two I'm aware of.
Johnf
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