Using psql how do I list extensions installed in a database?
In psql that would be
\dxSee the manual of psql for details.
Doing it in plain SQL it would be a select on pg_extension:
SELECT * FROM pg_extension;
Additionally if you want to know which extensions are available on your server: SELECT * FROM pg_available_extensions.
See pg_available_extensions and pg_available_extension_versions.
This SQL query gives output similar to \dx:
SELECT e.extname AS "Name", e.extversion AS "Version", n.nspname AS "Schema", c.description AS "Description" FROM pg_catalog.pg_extension e LEFT JOIN pg_catalog.pg_namespace n ON n.oid = e.extnamespace LEFT JOIN pg_catalog.pg_description c ON c.objoid = e.oid AND c.classoid = 'pg_catalog.pg_extension'::pg_catalog.regclass ORDER BY 1;Thanks to https://blog.dbi-services.com/listing-the-extensions-available-in-postgresql/