How to use IFNULL() function instead of COALESCE() function in MySQL?

We know that if the first parameter is not NULL, the IFNULL() function will return the first parameter, otherwise it will return the second parameter. The COALESCE() function, on the other hand, returns the first non-NULL argument. In fact, if there are only two parameters, the IFNULL() and COALESCE() functions in MySQL are equivalent. The reason behind this is that the IFNULL() function only accepts two parameters, in comparison, the COALECSE() function can accept any number of parameters.

Suppose we want to use the IFNULL() function in place of the COALESCE() function, the number of parameters must be two. The following example will demonstrate it -

mysql> Select IFNULL(NULL, 'Green');
+-----------------------+
| IFNULL(NULL, 'Green') |
+-----------------------+
| Green                 |
+-----------------------+
1 row in set (0.00 sec)

mysql> Select COALESCE(NULL, 'Green');
+-------------------------+
| COALESCE(NULL, 'Green') |
+-------------------------+
| Green                   |
+-------------------------+
1 row in set (0.00 sec)

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