The Ultimate Guide to High Availability with MariaDB
This is a read-only copy of the MariaDB Knowledgebase generated on 2024-11-14. For the latest, interactive version please visit https://mariadb.com/kb/.

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Sintassi

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Spiegazione

Uguale a prova di NULL. Questo operatore esegue una comparazione di uguaglianza come l'operatore =, ma restituisce 1 invece di NULL se entrambi gli operandi sono NULL, e 0 invece di NULL se solo un operando è NULL.

Esempi

MariaDB [(none)]> SELECT 1 <=> 1, NULL <=> NULL, 1 <=> NULL;
+---------+---------------+------------+
| 1 <=> 1 | NULL <=> NULL | 1 <=> NULL |
+---------+---------------+------------+
|       1 |             1 |          0 |
+---------+---------------+------------+
1 row in set (0.00 sec)

MariaDB [(none)]> SELECT 1 = 1, NULL = NULL, 1 = NULL;
+-------+-------------+----------+
| 1 = 1 | NULL = NULL | 1 = NULL |
+-------+-------------+----------+
|     1 |        NULL |     NULL |
+-------+-------------+----------+
1 row in set (0.00 sec)

MariaDB [(none)]>
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