MySQL CASE statement to place custom values in place of NULL
Let us first create a table −
mysql> create table DemoTable
(
FirstName varchar(20)
);
Query OK, 0 rows affected (1.15 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values('John');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable values(NULL);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable values('Adam');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values(NULL);
Query OK, 1 row affected (0.09 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+-----------+
| FirstName |
+-----------+
| John |
| NULL |
| Adam |
| NULL |
+-----------+
4 rows in set (0.00 sec)
Let us now use CASE statement −
mysql> select case when FirstName is NULL then 'UNKNOWN NAME' else FirstName end AS FirstName from DemoTable;
This will produce the following output −
+--------------+
| FirstName |
+--------------+
| John |
| UNKNOWN NAME |
| Adam |
| UNKNOWN NAME |
+--------------+
4 rows in set (0.00 sec)
We can also get the same results using IFNULL() −
mysql> select IFNULL(FirstName,'UNKNOWN NAME') AS FirstName from DemoTable;
This will produce the following output −
+--------------+
| FirstName |
+--------------+
| John |
| UNKNOWN NAME |
| Adam |
| UNKNOWN NAME |
+--------------+
4 rows in set (0.00 sec)
Published on 07-Oct-2019 15:32:58
