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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)
Updated on: 07-Oct-2019
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