Functions

A PostgreSQL function is used to provide a distinct service, and it is often composed of a set of declarations, expressions, and statements. PostgreSQL has very rich built-in functions for almost all existing data types. In this chapter, we will focus on user-defined functions. However, more details about the syntax and function parameters will be covered in later chapters.

The PostgreSQL native programming language

PostgreSQL supports out-of-the-box, user-defined functions, written in C, SQL, and PL/pgSQL. There are also three other procedural languages that come with the standard PostgreSQL distribution—PL/Tcl, PL/Python, and PL/Perl. However, you will need to create the languages in order to use them, via...