How do I get SUM function in MySQL to return '0' if no values are found?

To return Sum as ‘0’ if no values are found, use IFNULL or COALESCE commands.

The following is the syntax for IFNULL.

SELECT IFNULL(SUM(NULL), 0) AS aliasName;

Let us now implement the above syntax in the following query.

mysql> SELECT IFNULL(SUM(NULL), 0) AS SUMOFTWO;

The following is the output of the above query, which returns 0.

+----------+
| SUMOFTWO |
+----------+
|        0 |
+----------+
1 row in set (0.00 sec)

Here is the syntax for COALESCE.

mysql> SELECT COALESCE(SUM(NULL),0) as SUMOFTWO;

The following is the output that returns 0 using the SUM() function.

+----------+
| SUMOFTWO |
+----------+
|        0 |
+----------+
1 row in set (0.00 sec)