| SQL functionsBuiltin functionsDatabase systems have many builtin functions.
 
 Postgres functions
  Postgres is extensible.
  So you aren't limited to just the builtin functions — add your own.
  Functions can be written in any Postgres-supported language:
              
                PL/pgSQL: Builtin procedural language.
                Python
                Perl
                Add your own, e.g. LOLCODE.
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