MySQL COALESCE() ফাংশন দিয়ে NULL ভ্যালু আপডেট করা

Employee টেবিলে ID 5 ও 6-র Salary হল NULL:

mysql> SELECT * FROM Employee;
+----+--------+--------+
| ID | Name   | Salary |
+----+--------+--------+
| 1  | Gaurav | 50000  |
| 2  | Rahul  | 20000  |
| 3  | Advik  | 25000  |
| 4  | Aarav  | 65000  |
| 5  | Ram    | NULL   |
| 6  | Mohan  | NULL   |
+----+--------+--------+

COALESCE() ব্যবহার করে UPDATE করা:

mysql> UPDATE Employee SET Salary = COALESCE(Salary, 20000) WHERE Id = 5;
Query OK, 1 row affected (0.09 sec)

mysql> UPDATE Employee SET Salary = COALESCE(Salary, 30000) WHERE Id = 6;
Query OK, 1 row affected (0.06 sec)

mysql> SELECT * FROM Employee;
+----+--------+--------+
| ID | Name   | Salary |
+----+--------+--------+
| 1  | Gaurav | 50000  |
| 2  | Rahul  | 20000  |
| 3  | Advik  | 25000  |
| 4  | Aarav  | 65000  |
| 5  | Ram    | 20000  |
| 6  | Mohan  | 30000  |
+----+--------+--------+

COALESCE(Salary, 20000) মানে: Salary যদি NULL না হয় তাহলে সেটি রাখবে, NULL হলে 20000 সেট করবে।