For this, use IF() along with IS NULL property. Let us first create a table −
mysql> create table DemoTable ( Name varchar(100), CountryName varchar(100) ); Query OK, 0 rows affected (0.70 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values('Chris','US'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('Mike',NULL); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(Name) values('David'); Query OK, 1 row affected (0.38 sec) mysql> insert into DemoTable values('Bob','AUS'); Query OK, 1 row affected (0.45 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+-------+-------------+ | Name | CountryName | +-------+-------------+ | Chris | US | | Mike | NULL | | David | NULL | | Bob | AUS | +-------+-------------+ 4 rows in set (0.00 sec)
Following is the query to compare for NULL value and display value 1 for these values in a new MySQL column −
mysql> select Name,CountryName,If (CountryName IS NULL,1,0) AS CountDemo from DemoTable;
This will produce the following output −
+-------+-------------+-----------+ | Name | CountryName | CountDemo | +-------+-------------+-----------+ | Chris | US | 0 | | Mike | NULL | 1 | | David | NULL | 1 | | Bob | AUS | 0 | +-------+-------------+-----------+ 4 rows in set (0.00 sec)