getting list of columns from a query

On Sun, 22 Aug 2010 10:27:52 -0700, c k <shreeseva.learning@gmail.com>
wrote:

Hi all,
As I am using MS Access for a long time, many tools like ms access
provides
a way to get the list of columns from a query. (using filed list in combo
boxes in ms access). But is it possible to get such list of columns from
a
query where it is not known to the user, that which columns are defined
in
the base 'SELECT' statement? How? I dynamically created SQL statements
many
times this situation occurs where the columns are not fixed and we have
to
get the list of columns from such a query.
Thanks in advance.

I am removing psql-admin from the Cc to avoid crossposting. Besides, I
am not sure if it is on-topic there or not.

Which version of PostgreSQL? Anyway, if you create the SELECT statement
dynamically you could know a priori what columns would result, AFAIU.

--
Octavio.

On 08/22/2010 05:27 PM, c k wrote:

As I am using MS Access for a long time, many tools like ms access
provides a way to get the list of columns from a query. (using filed
list in combo boxes in ms access). But is it possible to get such list
of columns from a query where it is not known to the user, that which
columns are defined in the base 'SELECT' statement? How? I dynamically
created SQL statements many times this situation occurs where the
columns are not fixed and we have to get the list of columns from such
a query.

What language are you using, and what technique in that language are you
using? (ex. Java and JDBC, C# and ADO.NET, PHP and PDO, or PHP and
PostgreSQL native) Most of these provide a way to get to the column
names, but they're language- and technique-dependent.

Hello

2010/8/22 c k <shreeseva.learning@gmail.com>:

Hi all,
As I am using MS Access for a long time, many tools like ms access provides
a way to get the list of columns from a query. (using filed list in combo
boxes in ms access). But is it possible to get such list of columns from a
query where it is not known to the user, that which columns are defined in
the base 'SELECT' statement? How? I dynamically created SQL statements many
times this situation occurs where the columns are not fixed and we have to
get the list of columns from such a query.
Thanks in advance.

Yes, it is possible, you can get a description of prepared statement's
result. See: PQprepare, PQdescribePrepared, PQdescribePortal. These
functions are in client postgresql library -
http://www.postgresql.org/docs/8.4/interactive/libpq-exec.html#LIBPQ-EXEC-MAIN

Regards

Pavel Stehule

I am using PostgreSQL 8.4 on Fedora Linux 13 and using MS Access as the
front end for our application. It is not the problem associated with MS
Access. I got the some entries while searching for the said topic that
Oracle provides such facility.
DESCRIBE SELECT LIST which gives the details about the column names and data
types. I need such thing in postgresql, because users of my application can
execute custom query and then select the aggregate function to be applied to
the selected columns. This can be done using Pivot Table/Chart in MS Access,
but it is not sufficient, rather it will be better if postgres has support
for this.

Thanks and regards to all,

CPK

On Mon, Aug 23, 2010 at 4:56 AM, Pavel Stehule <pavel.stehule@gmail.com>wrote:

Isn't this provided in odbc by myQuery.columns? Is that not
accessible to MSAccess??

On Mon, Aug 23, 2010 at 2:02 AM, c k <shreeseva.learning@gmail.com> wrote:

I am using PostgreSQL 8.4 on Fedora Linux 13 and using MS Access as the
front end for our application. It is not the problem associated with MS
Access. I got the some entries while searching for the said topic that
Oracle provides such facility.
DESCRIBE SELECT LIST which gives the details about the column names and data
types. I need such thing in postgresql, because users of my application can
execute custom query and then select the aggregate function to be applied to
the selected columns. This can be done using Pivot Table/Chart in MS Access,
but it is not sufficient, rather it will be better if postgres has support
for this.

Thanks and regards to all,

CPK

On Mon, Aug 23, 2010 at 4:56 AM, Pavel Stehule <pavel.stehule@gmail.com>
wrote:

Hello

2010/8/22 c k <shreeseva.learning@gmail.com>:

Hi all,
As I am using MS Access for a long time, many tools like ms access
provides
a way to get the list of columns from a query. (using filed list in
combo
boxes in ms access). But is it possible to get such list of columns from
a
query where it is not known to the user, that which columns are defined
in
the base 'SELECT' statement? How? I dynamically created SQL statements
many
times this situation occurs where the columns are not fixed and we have
to
get the list of columns from such a query.
Thanks in advance.

Yes, it is possible, you can get a description of prepared statement's
result. See: PQprepare, PQdescribePrepared, PQdescribePortal. These
functions are in client postgresql library -

http://www.postgresql.org/docs/8.4/interactive/libpq-exec.html#LIBPQ-EXEC-MAIN

Regards

Pavel Stehule

CPK

--
To understand recursion, one must first understand recursion.