MySQL Tutorial/Data Types/Boolean

BOOL, BOOLEAN

These types are synonyms for TINYINT(1).

A value of zero is considered false.

Non-zero values are considered true:

The constants TRUE and FALSE evaluate to 1 and 0, respectively.

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mysql> mysql> SELECT TRUE, true, FALSE, false; +------+------+-------+-------+ | TRUE | TRUE | FALSE | FALSE | +------+------+-------+-------+ | 1 | 1 | 0 | 0 | +------+------+-------+-------+ 1 row in set (0.00 sec) mysql></source>

The values TRUE and FALSE are merely aliases for 1 and 0, respectively, as shown here:

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mysql> mysql> SELECT IF(0 = FALSE, "true", "false"); +--------------------------------+ | IF(0 = FALSE, "true", "false") | +--------------------------------+ | true | +--------------------------------+ 1 row in set (0.00 sec) mysql> SELECT IF(1 = TRUE, "true", "false"); +-------------------------------+ | IF(1 = TRUE, "true", "false") | +-------------------------------+ | true | +-------------------------------+ 1 row in set (0.00 sec) mysql> SELECT IF(2 = TRUE, "true", "false"); +-------------------------------+ | IF(2 = TRUE, "true", "false") | +-------------------------------+ | false | +-------------------------------+ 1 row in set (0.00 sec) mysql> SELECT IF(2 = FALSE, "true", "false"); +--------------------------------+ | IF(2 = FALSE, "true", "false") | +--------------------------------+ | false | +--------------------------------+ 1 row in set (0.00 sec) mysql></source>

Using if statement with BOOLEAN

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mysql> mysql> SELECT IF(0, "true", "false"); +------------------------+ | IF(0, "true", "false") | +------------------------+ | false | +------------------------+ 1 row in set (0.00 sec) mysql> SELECT IF(1, "true", "false"); +------------------------+ | IF(1, "true", "false") | +------------------------+ | true | +------------------------+ 1 row in set (0.00 sec) mysql> SELECT IF(2, "true", "false"); +------------------------+ | IF(2, "true", "false") | +------------------------+ | true | +------------------------+ 1 row in set (0.00 sec) mysql> mysql> mysql></source>