When working with an SQL database, especially in a development environment, it is easy to lose track of which databases are in which instance.
MySQL has a really convenient way of listing its databases with the command
in a client session or even programmatically. But then, structurally MySQL is a good deal simpler - or at least it was - than Postgres.
To get a similar result in Postgres can be done by querying the system tables:
SELECT datname FROM pg_database;
This is good to know as it can be used with other tables to get more sophisticated answers. For instance,
SELECT datname FROM pg_database JOIN pg_authid ON pg_database.datdba = pg_authid.oid WHERE rolname = 'novicedba'
selects only databases belonging to novicedba. And of course these statements can be executed programmatically too.
There are times when this level of sophistication is not required; perhaps we just want to see the proper name of a database so we can dump it. A simpler list can be rendered with
if you are in a Postgres session, or
from the command-line.