The Ultimate Guide to High Availability with MariaDB

NULLIF

Sintassi

NULLIF(espr1, espr2)

Spiegazione

Restituisce NULL se è vero che espr1 = espr2, altrimenti restituisce espr1. Questa espressione è equivalente a CASE WHEN espr1 = espr2 THEN NULL ELSE espr1 END.

Esempi

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

MariaDB [(none)]> SELECT NULLIF(1,2);
+-------------+
| NULLIF(1,2) |
+-------------+
|           1 |
+-------------+
1 row in set (0.00 sec)

MariaDB [(none)]>

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