Using CASE statement in MySQL to display custom name for empty value

For this, you can use CASE WHEN statement. Let us first create a table −

mysql> create table DemoTable
   -> (
   -> Name varchar(20)
   -> );
Query OK, 0 rows affected (0.62 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('Chris');
Query OK, 1 row affected (0.15 sec)
mysql> insert into DemoTable values('');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values('David');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values('');
Query OK, 1 row affected (0.11 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+-------+
| Name  |
+-------+
| Chris |
|       |
| David |
|       |
+-------+
4 rows in set (0.00 sec)

Following is the query to display custom name for empty values −

mysql> select case trim(ifnull(Name,''))
   -> when '' then 'Carol Taylor'
   -> else
   -> Name
   -> end as Name
   -> from DemoTable;

This will produce the following output −

+--------------+
| Name         |
+--------------+
| Chris        |
| Carol Taylor |
| David        |
| Carol Taylor |
+--------------+
4 rows in set (0.03 sec)

AmitDiwan

Published on 13-Dec-2019 11:39:56