boolean

logical Boolean (true/false)

Reading PostgreSQL 18.6.

PG10–20 core source inventory. Casts and operator classes show explicitly declared relationships; absent rows do not rule out coercions or indexing through other mechanisms.

Definition

SQL names and aliases: bool

logical Boolean (true/false)

boolean

Catalog name: pg_catalog.bool
Type OID: 16
Type kind: Base type
Declared length: 1 byte
Storage strategy: plain
Input function: boolin
Output function: boolout
Documented declaration: boolean
Storage Size: 1 byte
Manual description: state of true or false

English manual

Read the complete manual section

Read the source definition

8.6. Boolean Type

PostgreSQL provides the standard SQL type boolean; see Table 8.19. The boolean type can have several states: “true”, “false”, and a third state, “unknown”, which is represented by the SQL null value.

Table 8.19. Boolean Data Type

Name	Storage Size	Description
`boolean`	1 byte	state of true or false

Boolean constants can be represented in SQL queries by the SQL key words TRUE, FALSE, and NULL.

The datatype input function for type boolean accepts these string representations for the “true” state:

true

yes

on

1

and these representations for the “false” state:

false

no

off

0

Unique prefixes of these strings are also accepted, for example t or n. Leading or trailing whitespace is ignored, and case does not matter.

The datatype output function for type boolean always emits either t or f, as shown in Example 8.2.

Example 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

The key words TRUE and FALSE are the preferred (SQL-compliant) method for writing Boolean constants in SQL queries. But you can also use the string representations by following the generic string-literal constant syntax described in Section 4.1.2.7, for example 'yes'::boolean.

Note that the parser automatically understands that TRUE and FALSE are of type boolean, but this is not so for NULL because that can have any type. So in some contexts you might have to cast NULL to boolean explicitly, for example NULL::boolean. Conversely, the cast can be omitted from a string-literal Boolean value in contexts where the parser can deduce that the literal must be of type boolean.

Catalog attributes

Source bootstrap values for this build. See pg_type for field meanings. Header defaults are included; build-dependent constants remain symbolic. This is not a live-server measurement.

oid: 16
descr: boolean, format 't'/'f'
typacl: _null_
typlen: 1
typelem: 0
typname: bool
typsend: boolsend
typtype: b
typalign: c
typarray: 0
typbyval: t
typdelim: ','
typinput: boolin
typmodin: -
typndims: 0
typowner: POSTGRES
typrelid: 0
typmodout: -
typoutput: boolout
typtypmod: -1
typanalyze: -
typdefault: _null_
typnotnull: f
typreceive: boolrecv
typstorage: p
typbasetype: 0
typcategory: B
typcollation: 0
typisdefined: t
typnamespace: pg_catalog
typsubscript: -
typdefaultbin: _null_
array_type_oid: 1000
typispreferred: t
array_type_name: _bool

Catalog casts 6

Explicit pg_cast records involving this type. PostgreSQL also supports coercions outside pg_cast; an absent row does not prove that a conversion is impossible.

From	To	Context	Method	Function
`int4`	`bool`	`Explicit`	`Function`	`bool(int4)`
`bool`	`int4`	`Explicit`	`Function`	`int4(bool)`
`bool`	`text`	`Assignment`	`Function`	`text(bool)`
`bool`	`varchar`	`Assignment`	`Function`	`text(bool)`
`bool`	`bpchar`	`Assignment`	`Function`	`text(bool)`
`jsonb`	`bool`	`Explicit`	`Function`	`bool(jsonb)`

Operator overloads 6

Each operand signature is a separate overload. Catalog implementation functions and result types belong to the same source build.

Operator	Left operand	Right operand	Result	Meaning	Implementation
`<`	`bool`	`bool`	`bool`	`less than`	`boollt`
`>`	`bool`	`bool`	`bool`	`greater than`	`boolgt`
`<>`	`bool`	`bool`	`bool`	`not equal`	`boolne`
`=`	`bool`	`bool`	`bool`	`equal`	`booleq`
`<=`	`bool`	`bool`	`bool`	`less than or equal`	`boolle`
`>=`	`bool`	`bool`	`bool`	`greater than or equal`	`boolge`

Operator classes 2

Operator classes whose declared input type matches this type. Polymorphic classes, casts and expression indexes can provide additional index paths; this list is not an exhaustive yes/no index-support test.

Class	Index method	Input type	Family	Default	Storage type
`bool_ops`	`btree`	`bool`	`btree/bool_ops`	`Yes`	`Same as input`
`bool_ops`	`hash`	`bool`	`hash/bool_ops`	`Yes`	`Same as input`

Version comparison

PostgreSQL 17.11 → 18.6. Source build identifiers and prose are excluded from attribute changes.

No catalog or structured attribute changes between these samples.

The documentation also differs between these builds; inspect the versioned manual definitions.

Documentation and source

Build: 18.6 · https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2
Fingerprint: 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f

Related entries

All Data Types · Download this version as JSON · The first recorded sample does not establish when a type was introduced.