Multiplying column with NULL row in MySQL?

To multiply with NULL row, you can use COALESCE(). Let us first create a table −

mysql> create table DemoTable1842      (      NumberOfItems int,      Amount int      ); Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1842 values(10,40); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1842 values(20,5); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1842 values(NULL,10); Query OK, 1 row affected (0.00 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1842;

This will produce the following output −

+---------------+--------+ | NumberOfItems | Amount | +---------------+--------+ |            10 |     40 | |            20 |      5 | |          NULL |     10 | +---------------+--------+ 3 rows in set (0.00 sec)

Here is the query to multiply column with NULL rows −

mysql> select NumberOfItems,Amount,      coalesce(NumberOfItems,1)*Amount as Total      from DemoTable1842;

This will produce the following output −

+---------------+--------+-------+ | NumberOfItems | Amount | Total | +---------------+--------+-------+ |            10 |     40 |   400 | |            20 |      5 |   100 | |          NULL |     10 |    10 | +---------------+--------+-------+ 3 rows in set (0.00 sec)