When MySQL arithmetic expression returns NULL?

We know that NULL is not a value and it is different from zero. MySQL arithmetic expression will return NULL if we use NULL in it. It can be understood through the following example -

Example

mysql> Select 100*NULL;
+----------+
| 100*NULL |
+----------+
|     NULL |
+----------+
1 row in set (0.00 sec)

mysql> Select 100+NULL;
+----------+
| 100+NULL |
+----------+
|     NULL |
+----------+
1 row in set (0.00 sec)

As can be seen from the above example, if we use NULL in an arithmetic expression, then the result itself is NULL .

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