IS NOT
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The parent of this page is: SQL Operators for MariaDB Xpand
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Overview
Negated boolean comparison.
USAGE
expression IS NOT TRUE|FALSE|UNKNOWN
Value Name | Description |
|---|---|
| A value expression |
DETAILS
The IS NOT operator returns a truth value for one of 3 negated boolean comparisons:
x IS NOT TRUEchecks if the expression does not evaluate toTRUE(is not a non-zero value)x IS NOT FALSEchecks if the expression does not evaluate toFALSE(is not a zero value)x IS NOT UNKNOWNchecks if the expression has a known value (is notNULL)
The return value is always 1 (true) or 0 (false). Evaluating a NULL value does not return NULL because this operator considers it to be UNKNOWN and never TRUE or FALSE.
See IS for the positive version of these comparisons.
EXAMPLES
SELECT 1 IS NOT TRUE, 1 IS NOT FALSE, 1 IS NOT UNKNOWN;
+---------------+----------------+------------------+
| 1 IS NOT TRUE | 1 IS NOT FALSE | 1 IS NOT UNKNOWN |
+---------------+----------------+------------------+
| 0 | 1 | 1 |
+---------------+----------------+------------------+
SELECT 0 IS NOT TRUE, 0 IS NOT FALSE, 0 IS NOT UNKNOWN;
+---------------+----------------+------------------+
| 0 IS NOT TRUE | 0 IS NOT FALSE | 0 IS NOT UNKNOWN |
+---------------+----------------+------------------+
| 1 | 0 | 1 |
+---------------+----------------+------------------+
SELECT NULL IS NOT TRUE, NULL IS NOT FALSE, NULL IS NOT UNKNOWN;
+------------------+-------------------+---------------------+
| NULL IS NOT TRUE | NULL IS NOT FALSE | NULL IS NOT UNKNOWN |
+------------------+-------------------+---------------------+
| 1 | 1 | 0 |
+------------------+-------------------+---------------------+
SELECT 42 != TRUE, 42 IS NOT TRUE;
+------------+----------------+
| 42 != TRUE | 42 IS NOT TRUE |
+------------+----------------+
| 1 | 0 |
+------------+----------------+