PostgreSQL Tutorial: PL/pgSQL

November 6, 2023

This section shows you step by step how to use the PL/pgSQL to develop PostgreSQL user-defined functions and stored procedures.


PL/pgSQL procedural language adds many procedural elements, e.g., control structures, loops, and complex computations, to extend standard SQL. It allows you to develop complex functions and stored procedures in PostgreSQL that may not be possible using plain SQL.

PL/pgSQL procedural language is similar to the Oracle PL/SQL. The following are reasons to learn PL/pgSQL:

  • PL/pgSQL is easy to learn and simple to use.
  • PL/pgSQL comes with PostgreSQL by default. The user-defined functions and stored procedures developed in PL/pgSQL can be used like any built-in functions and stored procedures.
  • PL/pgSQL inherits all user-defined types, functions, and operators.
  • PL/pgSQL has many features that allow you to develop complex functions and stored procedures.
  • PL/pgSQL can be defined to be trusted by the PostgreSQL database server.

Let’s get started programming with PL/pgSQL.

Section 1. Getting started

Section 2. Variables & constants

  • Variables – show you how to declare variables in PL/pgSQL.
  • Select into – guide you on how to use the select into to select data and assign it to a variable.
  • Row type variables – learn how to use the row variables to store a complete row of a result set.
  • Record type variables – show you how to declare record variables to hold a single row of a result set.
  • Constants – guide you on how to use constants to make the code more readable and easier to maintain.

Section 3. Reporting messages and errors

Section 4. Control structures

  • If statement – introduce you to three forms of the if statement.
  • Case statements – explain case statements including the simple and searched case statements.
  • Loop statements – show you how to use loop statements to execute a block of code repeatedly based on a condition.
  • While loop – learn how to use while loop statement to create a pre-test loop.
  • For loop – show you how to use the for loop statement to iterate over rows of a result set.
  • Exit – guide you on using the exit statement to terminate a loop.
  • Continue – provide you with a way to use the continue statement to skip the current loop iteration and start a new one.

Section 5. User-defined functions

Section 6. Exception handling

  • Handling exceptions – show you how to use the exception clause to catch and handle exceptions.

Section 7. Stored procedures

Section 8. Cursors

  • Cursors – show you how to use cursors to process a result set, row by row.

Section 9. Trigger functions

Section 10. Debugging

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