How to list all schema names inside a PostgreSQL database through SQL

2012/11/15 Xiaobo Gu <guxiaobo1982@gmail.com>:

How can I list all schema names inside a PostgreSQL database through
SQL, especially thoese without any objects created inside it.

Something like this:
select n.nspname, count(o.oid)
from pg_namespace n
left join pg_class o on n.oid=o.relnamespace
group by 1
order by count(o.oid)>0, 1;

I prefer to query PostgreSQL catalogs.
You can obtain the same information using information_schema queries.

--
Victor Y. Yegorov

On Πεμ 15 Νοε 2012 20:31:05 Xiaobo Gu wrote:

Hi,

How can I list all schema names inside a PostgreSQL database through
SQL, especially thoese without any objects created inside it.

1st solution :

select catalog_name,schema_name from information_schema.schemata ;

2nd solution :

select * from pg_namespace ;

Regards,

Xiaobo Gu

-
Achilleas Mantzios
IT DEPT

If you are looking for list of empty schema's (No objects in schema), then
you can use below query:

select nspname from pg_namespace where oid not in (select relnamespace from
pg_class) and oid not in (select oid from pg_proc);

Regards,
Baji Shaik.

On Thu, Nov 15, 2012 at 6:13 PM, Achilleas Mantzios <
achill@matrix.gatewaynet.com> wrote:

Hi,

On 15 November 2012 23:31, Xiaobo Gu <guxiaobo1982@gmail.com> wrote:

How can I list all schema names inside a PostgreSQL database through
SQL, especially thoese without any objects created inside it.

Use -E psql's option:
-E, --echo-hidden display queries that internal commands generate

then you get SQL query for each internal command.

The second option is to use information_schema.schemata view (this is
works across databases)

--
Ondrej Ivanic
(http://www.linkedin.com/in/ondrejivanic)

Thanks a lot.

Thanks a lot.