PostgreSQL, Second Edition

Boolean (Logical) Values

PostgreSQL supports a single Boolean (or logical) data type: BOOLEAN (BOOLEAN can be abbreviated as BOOL).

Size and Valid Values

A BOOLEAN can hold the values TRUE, FALSE, or NULL, and consumes a single byte of storage.

Syntax for Literal Values

Table 2.16 shows the alternate spellings for BOOLEAN literals.

Table 2.16. BOOLEAN Literal Syntax

Common Name	Synonyms
TRUE	true, 't', 'y', 'yes', 1
FALSE	false, 'f', 'n', 'no', 0

Supported Operators

The only operators supported for the BOOLEAN data type are the logical operators shown in Table 2.17:

Table 2.17. Logical Operators for BOOLEAN

Data Types	Valid Operators (θ)
BOOLEAN θ BOOLEAN	AND OR NOT

I covered the AND, OR, and NOT operators in Chapter 1. For a complete definition of these ...