TO_BOOLEAN¶

Syntax¶

TO_BOOLEAN( <string_or_numeric_expr> )

Arguments¶

string_or_numeric_expr

A string expression or numeric expression that can be evaluated to a BOOLEAN value.

Returns¶

Returns a BOOLEAN value or NULL.

• Returns TRUE if string_or_numeric_expr evaluates to TRUE.

• Returns FALSE if string_or_numeric_expr evaluates to FALSE.

• If the input is NULL, returns NULL without reporting an error.

Usage notes¶

• For a string expression:

  • 'true', 't', 'yes', 'y', 'on', '1' return TRUE.

  • 'false', 'f', 'no', 'n', 'off', '0' return FALSE.

  • All other strings return an error.

  The evaluations of the strings are case-insensitive.

• For a numeric expression:

  • 0 returns FALSE.

  • All non-zero numeric values return TRUE.

  • When converting from the FLOAT data type, non-numeric values, such as NaN (not a number) and INF (infinity), return an error.

Examples¶

The following examples use the TO_BOOLEAN function.

Create a table and insert data:

CREATE OR REPLACE TABLE test_boolean(
  b BOOLEAN,
  n NUMBER,
  s STRING);

INSERT INTO test_boolean VALUES
  (true, 1, 'yes'),
  (false, 0, 'no'),
  (null, null, null);

SELECT * FROM test_boolean;

+-------+------+------+
| B     |    N | S    |
|-------+------+------|
| True  |    1 | yes  |
| False |    0 | no   |
| NULL  | NULL | NULL |
+-------+------+------+

Convert a text string to a BOOLEAN value:

SELECT s, TO_BOOLEAN(s) FROM test_boolean;

+------+---------------+
| S    | TO_BOOLEAN(S) |
|------+---------------|
| yes  | True          |
| no   | False         |
| NULL | NULL          |
+------+---------------+

Convert a number to a BOOLEAN value:

SELECT n, TO_BOOLEAN(n) FROM test_boolean;

+------+---------------+
|    N | TO_BOOLEAN(N) |
|------+---------------|
|    1 | True          |
|    0 | False         |
| NULL | NULL          |
+------+---------------+