Is there a way to easily get the column types of a query result? I read the psql documentation, but I don't think it supports that. Ideally, I'd be able to get something like:
columna : text | columnb : integer
----------------+-------------------
oh hai | 42
Is there a way I can get this information without coding something up?
It is possible to get any SELECT query result column type.
Example
Given the following query and result, let's answer the question *"What is the column type of all_ids?"*
SELECT array_agg(distinct "id") "all_ids" FROM "auth_user";
all_ids
--------------------------------------------
{30,461577687337538580,471090357619135524}
(1 row)
We need a mechanism to unveil the type of "all_ids".
On the postgres mailing list archives I found reference to a native pg function called pg_typeof.
Example usage:
SELECT pg_typeof(array_agg(distinct "id")) "all_ids" FROM "auth_user";
Output:
all_ids
----------
bigint[]
(1 row)
Cheers!
It is definitely possible with \gdesc command(psql 11):
Shows the description (that is, the column names and data types) of the result of the current query buffer. The query is not actually executed; however, if it contains some type of syntax error, that error will be reported in the normal way.
If the current query buffer is empty, the most recently sent query is described instead.
For example:
$ SELECT * FROM pg_database \gdesc
COLUMN | TYPE
---------------+-----------
datname | name
datdba | oid
encoding | INTEGER
datcollate | name
datctype | name
datistemplate | BOOLEAN
datallowconn | BOOLEAN
datconnlimit | INTEGER
datlastsysoid | oid
datfrozenxid | xid
datminmxid | xid
dattablespace | oid
datacl | aclitem[]
psql to access older PostgreSQL server, e.g. apt install postgresql-client-11I don't think you can print exactly what you have in the sample, unless you write a stored procedure for it.
One way to do it (two "selects"):
create table my_table as select ...\d my_tableselect * from my_table
pg_typeof().
In Postgres 16+, It's possible to get the column types without even running the query by preparing it and then inspecting pg_prepared_statements:
postgres=# prepare test as select 1::int, '{2,3}'::int[];
postgres=# select result_types from pg_prepared_statements where name = 'test';
┌─────────────────────┐
│ result_types │
├─────────────────────┤
│ {integer,integer[]} │
└─────────────────────┘
(1 row)
psqlcan show it to you directly. But it should be fairly easy to modify it to do so. Perhaps you could write a stored procedure to emulate this though.