What is the output of the MySQL SUM() function if a column with no value is passed as a parameter?

When the MySQL SUM() function takes a column with no value as a parameter, it returns NULL instead of 0 as output. The column can be of any data type. As per the following example, using a table named "social" which has only one column named "id" with no value, it will be explained

Example

mysql> Describe Social;
+-------+-------------+------+-----+---------+-------+
| Field | Type        | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| Id    | int(11)     | YES  |     |   NULL  |       |
| Name  | varchar(20) | YES  |     |    NULL |       |
+-------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql> Select * from Social;
Empty set (0.00 sec)

mysql> Select SUM(id) from Social;
+---------+
| SUM(id) |
+---------+
| NULL    |
+---------+
1 row in set (0.00 sec)

mysql> Select SUM(Name) from Social;
+-----------+
| SUM(Name) |
+-----------+
| NULL      |
+-----------+
1 row in set (0.00 sec)

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