+-----+--------------+-------+
|Num  |  Name        | Amount|
+-----+--------------+-------+
|  1  | Kate         |  15   |
|  2  | Misha        | NULL  |
|  3  | Nick         |  0    |
|  4  | Larisa       |  20   |
+-----+--------------+-------+

SELECT COUNT(Amount) FROM People;