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

• Boolean Literals

• IS operator

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