BOOLEAN
Syntax
BOOL, BOOLEAN
Description
These types are synonyms for TINYINT(1). A value of zero is considered false. Non-zero values are considered true.
However, the values TRUE and FALSE are merely aliases for 1 and 0. See Boolean Literals, as well as the IS operator for testing values against a boolean.
Examples
CREATE TABLE boolean_example ( example BOOLEAN );
SHOW CREATE TABLE boolean_example\G
*************************** 1. row *************************** Table: boolean_example Create Table: CREATE TABLE `boolean_example` ( `example` tinyint(1) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=latin1
CREATE TABLE boo (i BOOLEAN); DESC boo; +-------+------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+------------+------+-----+---------+-------+ | i | tinyint(1) | YES | | NULL | | +-------+------------+------+-----+---------+-------+
SELECT IF(0, 'true', 'false'); +------------------------+ | IF(0, 'true', 'false') | +------------------------+ | false | +------------------------+ SELECT IF(1, 'true', 'false'); +------------------------+ | IF(1, 'true', 'false') | +------------------------+ | true | +------------------------+ SELECT IF(2, 'true', 'false'); +------------------------+ | IF(2, 'true', 'false') | +------------------------+ | true | +------------------------+
TRUE and FALSE as aliases for 1 and 0:
SELECT IF(0 = FALSE, 'true', 'false'); +--------------------------------+ | IF(0 = FALSE, 'true', 'false') | +--------------------------------+ | true | +--------------------------------+ SELECT IF(1 = TRUE, 'true', 'false'); +-------------------------------+ | IF(1 = TRUE, 'true', 'false') | +-------------------------------+ | true | +-------------------------------+ SELECT IF(2 = TRUE, 'true', 'false'); +-------------------------------+ | IF(2 = TRUE, 'true', 'false') | +-------------------------------+ | false | +-------------------------------+ SELECT IF(2 = FALSE, 'true', 'false'); +--------------------------------+ | IF(2 = FALSE, 'true', 'false') | +--------------------------------+ | false | +--------------------------------+
The last two statements display the results shown because 2 is equal to neither 1 nor 0.
See Also
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