If I supply NULL to MySQL's CHAR_LENGTH() function, what does it return?

In this case, the output of CHAR_LENGTH() function depends on the condition that whether we are providing NULL as a string or we are providing simply NULL to it. Following example will demonstrate the difference −

mysql> Select CHAR_LENGTH(NULL);
+-------------------+
| CHAR_LENGTH(NULL) |
+-------------------+
| NULL              |
+-------------------+
1 row in set (0.00 sec)

mysql> Select CHAR_LENGTH('NULL');
+---------------------+
| CHAR_LENGTH('NULL') |
+---------------------+
| 4                   |
+---------------------+
1 row in set (0.00 sec)

It can be observed from the above result set that when we provide NULL as string, CHAR_LENGTH() function will return the number of characters i.e. 4 characters otherwise when we provide only NULL , it will return NULL as output.

The above is the detailed content of If I supply NULL to MySQL's CHAR_LENGTH() function, what does it return?. For more information, please follow other related articles on the PHP Chinese website!