Historical version. PostgreSQL 9.5 has reached end of support. 2021-02-11. See the current manual.
35.7. Procedural Language Functions
PostgreSQL allows user-defined functions to be written in other languages besides SQL and C. These other languages are generically called procedural languages (PLs). Procedural languages aren't built into the PostgreSQL server; they are offered by loadable modules. See Chapter 39 and following chapters for more information.
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