Documentação do PostgreSQL 8.2.0
Anterior	Início	Capítulo 8. Data Types	Fim	Próxima

8.6. Boolean Type

PostgreSQL provides the standard SQL type boolean. boolean can have one of only two states: "true" or "false". A third state, "unknown", is represented by the SQL null value.

Valid literal values for the "true" state are:

TRUE

't'

'true'

'y'

'yes'

'1'

For the "false" state, the following values can be used:

FALSE

'f'

'false'

'n'

'no'

'0'

Using the key words TRUE and FALSE is preferred (and SQL-compliant).

Exemplo 8-2. Using the boolean type

CREATE TABLE test1 (a boolean, b text);
INSERT INTO test1 VALUES (TRUE, 'sic est');
INSERT INTO test1 VALUES (FALSE, 'non est');
SELECT * FROM test1;
 a |    b
---+---------
 t | sic est
 f | non est

SELECT * FROM test1 WHERE a;
 a |    b
---+---------
 t | sic est

Exemplo 8-2 shows that boolean values are output using the letters t and f.

boolean uses 1 byte of storage.

Anterior	Principal	Próxima
Date/Time Types	Acima	Geometric Types