Обсуждение: Can psql show the column type of a result ?
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.
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. > > > -- > 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)$' AND a.attnum > 0 AND NOT a.attisdropped ORDER BY a.attnum; -- Regards, Richard Broersma Jr. Visit the Los Angeles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug
=?UTF-8?B?Ik5pbHMgTy4gU2Vsw6VzZGFsIg==?= <noselasd@asgaard.homelinux.org> writes:
> I'm wondering if there's a way to show the column type of a result with
> psql, e.g.
>>> select sum(r) from mytable;
> r
> -------
> 101.0
> I'd like to see the type of the 'r' column.
There's nothing built-in to psql, but you could modify the query, eg
select pg_typeof(sum(r)) from mytable;
(Adding "LIMIT 1" would be wise in most cases, though you don't need it
here.)
regards, tom lane
On 22.09.2010 23:26, Richard Broersma wrote: > On Wed, Sep 22, 2010 at 12:52 PM, "Nils O. Selåsdal" > <noselasd@asgaard.homelinux.org> wrote: >> Hello, >> I'm wondering if there's a way to show the column type of a result with >> psql, e.g. >> >>> select sum(r) from mytable; >> r >> ------- >> 101.0 >> >> I'd like to see the type of the 'r' column. >> >> >> -- >> Sent via pgsql-general mailing list (pgsql-general@postgresql.org) >> To make changes to your subscription: >> http://www.postgresql.org/mailpref/pgsql-general >> > > From psql you can use: > > \d mytable > > sql to show this might look like: > > SELECT a.attname, > pg_catalog.format_type(a.atttypid, a.atttypmod), > (SELECT substring(pg_catalog.pg_get_expr(d.adbin, d.adrelid) for 128) > FROM pg_catalog.pg_attrdef d > WHERE d.adrelid = a.attrelid AND d.adnum = a.attnum AND a.atthasdef), > a.attnotnull, a.attnum > FROM pg_catalog.pg_attribute AS a > INNER JOIN pg_catalog.pg_class c > ON C.oid = a.attrelid > WHERE c.relname ~ '^(mytable)$' 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.