Boolean

Overview

BOOLEAN (alias BOOL) represents TRUE or FALSE and always uses one byte of storage. Numeric and string inputs automatically coerce to boolean values when possible.

Examples

SELECT
  0::BOOLEAN            AS zero_is_false,
  42::BOOLEAN           AS nonzero_is_true,
  'True'::BOOLEAN       AS string_true,
  'false'::BOOLEAN      AS string_false;

Result:

┌───────────────┬──────────────────┬───────────────┬────────────────┐
│ zero_is_false │ nonzero_is_true  │ string_true   │ string_false   │
├───────────────┼──────────────────┼───────────────┼────────────────┤
│ false         │ true             │ true          │ false          │
└───────────────┴──────────────────┴───────────────┴────────────────┘

-- Casting unsupported text raises an error.
SELECT 'yes'::BOOLEAN;

Result:

ERROR 1105 (HY000): QueryFailed: [1006]cannot parse to type `BOOLEAN` while evaluating function `to_boolean('yes')` in expr `CAST('yes' AS Boolean)`