Set a custom value for NULL or empty values in MySQL

Let us first create a table −

mysql> create table DemoTable
(
   Value varchar(100)
);
Query OK, 0 rows affected (0.75 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('100');
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable values('');
Query OK, 1 row affected (0.09 sec)
mysql> insert into DemoTable values('200');
Query OK, 1 row affected (0.06 sec)
mysql> insert into DemoTable values(null);
Query OK, 1 row affected (0.12 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+-------+
| Value |
+-------+
| 100   |
|       |
| 200   |
| NULL  |
+-------+
4 rows in set (0.00 sec)

Following is the query to set a custom value for NULL or empty values −

mysql> select if(Value IS NULL or Value='','Garbage Value',Value) AS Result from DemoTable;

This will produce the following output −

+---------------+
| Result        |
+---------------+
| 100           |
| Garbage Value |
| 200           |
| Garbage Value |
+---------------+
4 rows in set (0.00 sec)