Set the NULL values to 0 and display the entire column in a new column with MySQL SELECT

For this, use IFNULL(). Let us first create a table −

mysql> create table DemoTable (Value int); Query OK, 0 rows affected (1.02 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(20); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(NULL); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(30); Query OK, 1 row affected (0.13 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

This will produce the following output −

+-------+ | Value | +-------+ | NULL | | 10 | | 20 | | NULL | | 30 | +-------+ 5 rows in set (0.00 sec)

Set NULL values to 0 −

mysql> select Value,IFNULL(Value,0) from DemoTable;

This will produce the following output −

+-------+-----------------+ | Value | IFNULL(Value,0) | +-------+-----------------+ | NULL  | 0               | | 10    | 10              | | 20    | 20             | | NULL | 0 | | 30 | 30 | +-------+-----------------+ 5 rows in set (0.00 sec)