MySQL ASCII Function Return for NULL

In this case, the output of ASCII() 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 ASCII(null);
+-------------+
| ASCII(null) |
+-------------+
| NULL        |
+-------------+
1 row in set (0.00 sec)

mysql> SELECT ASCII('null');
+---------------+
| ASCII('null') |
+---------------+
| 110           |
+---------------+
1 row in set (0.00 sec)

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

mysql> Select ASCII('NULL');
+---------------+
| ASCII('NULL') |
+---------------+
| 78            |
+---------------+
1 row in set (0.00 sec)

As we can observe from the above result set that when we will provide NULL or null as a string, ASCII() function will return the number code of the first character i.e. number code of N in case of ‘NULL’ and number code of n in case of ‘null’, otherwise when we provide simply NULL then it returns NULL as output.