Can psql show the column type of a result ?

On Wed, Sep 22, 2010 at 12:52 PM, "Nils O. Selåsdal"
<noselasd@asgaard.homelinux.org> wrote:

 Hello,
I'm wondering if there's a way to show the column type of a result with
psql, e.g.

select sum(r) from mytable;

  r
-------
 101.0

I'd like to see the type of the 'r' column.

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From psql you can use:

\d mytable

sql to show this might look like:

SELECT a.attname,
pg_catalog.format_type(a.atttypid, a.atttypmod),
(SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef),
a.attnotnull, a.attnum
FROM pg_catalog.pg_attribute AS a
INNER JOIN pg_catalog.pg_class c
ON C.oid = a.attrelid
WHERE c.relname ~ '^(mytable)$' AND a.attnum > 0 AND NOT a.attisdropped
ORDER BY a.attnum;

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Regards,
Richard Broersma Jr.

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On 22.09.2010 23:26, Richard Broersma wrote:

On Wed, Sep 22, 2010 at 12:52 PM, "Nils O. Sel�sdal"
<noselasd@asgaard.homelinux.org> wrote:

Hello,
I'm wondering if there's a way to show the column type of a result with
psql, e.g.

select sum(r) from mytable;

r
-------
101.0

I'd like to see the type of the 'r' column.

--
Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general

From psql you can use:

\d mytable

sql to show this might look like:

SELECT a.attname,
pg_catalog.format_type(a.atttypid, a.atttypmod),
(SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128)
FROM pg_catalog.pg_attrdef d
WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef),
a.attnotnull, a.attnum
FROM pg_catalog.pg_attribute AS a
INNER JOIN pg_catalog.pg_class c
ON C.oid = a.attrelid
WHERE c.relname ~ '^(mytable)$' AND a.attnum> 0 AND NOT a.attisdropped
ORDER BY a.attnum;

This is ok for showing tables, but insufficient for showing the type of
a result set, which might
differ from the table being queried ,depending on what
operators/constants/functions a query uses to pull out data
- which was my current problem.

=?UTF-8?B?Ik5pbHMgTy4gU2Vsw6VzZGFsIg==?= <noselasd@asgaard.homelinux.org> writes:

I'm wondering if there's a way to show the column type of a result with
psql, e.g.

select sum(r) from mytable;

r
-------
101.0

I'd like to see the type of the 'r' column.

There's nothing built-in to psql, but you could modify the query, eg

select pg_typeof(sum(r)) from mytable;

(Adding "LIMIT 1" would be wise in most cases, though you don't need it
here.)

regards, tom lane