PostgreSQL: Check if Procedural Language is installed

To check if a procedural language is installed on PostgreSQL, just run the following:

SELECT COUNT(*) FROM pg_language WHERE lanname = 'plpgsql';

Values for lanname can be one of the following:

• plsql
• pltcl
• plperl
• plpython

References:

• PostgreSQL documentation on procedural languages
• This SQL code snippet from polak.ro