November 13, 2025: PostgreSQL 18.1, 17.7, 16.11, 15.15, 14.20, and 13.23 Released!

Supported Versions: Current (18) / 17 / 16 / 15 / 14

Development Versions: devel

Unsupported versions: 13 / 12 / 11 / 10 / 9.6 / 9.5 / 9.4 / 9.3 / 9.2 / 9.1 / 9.0 / 8.4 / 8.3 / 8.2 / 8.1 / 8.0 / 7.4 / 7.3 / 7.2 / 7.1

This documentation is for an unsupported version of PostgreSQL.
You may want to view the same page for the current version, or one of the other supported versions listed above instead.

PostgreSQL 8.2.23 Documentation
Prev	Fast Backward	Fast Forward	Next

Chapter 4. SQL Syntax

Table of Contents

4.1. Lexical Structure

4.1.1. Identifiers and Key Words
4.1.2. Constants
4.1.3. Operators
4.1.4. Special Characters
4.1.5. Comments
4.1.6. Lexical Precedence

4.2. Value Expressions

4.2.1. Column References
4.2.2. Positional Parameters
4.2.3. Subscripts
4.2.4. Field Selection
4.2.5. Operator Invocations
4.2.6. Function Calls
4.2.7. Aggregate Expressions
4.2.8. Type Casts
4.2.9. Scalar Subqueries
4.2.10. Array Constructors
4.2.11. Row Constructors
4.2.12. Expression Evaluation Rules

This chapter describes the syntax of SQL. It forms the foundation for understanding the following chapters which will go into detail about how the SQL commands are applied to define and modify data.

We also advise users who are already familiar with SQL to read this chapter carefully because there are several rules and concepts that are implemented inconsistently among SQL databases or that are specific to PostgreSQL.

Prev	Home	Next
The SQL Language	Up	Lexical Structure