Question

Hi I am trying to create a SQL query were I multiply the values of 1 row by the values in its column in the row beneath it. How can I do it? multiplying two columns is easy but i seem stuck on multiplying 2 rows.

Answer 1

That depends on your situation.

To simplyfy it… if your table looks like this…

CREATE TABLE `test` (
  `number` BIGINT(20) NOT NULL,
  PRIMARY KEY (`number`)
) ENGINE=INNODB DEFAULT CHARSET=latin1

… and some data in it like this…

number
------
     2
     3
     4

…you can do something like this:

SELECT 
  (SELECT number 
  FROM test 
  WHERE number = 2) * 
  (SELECT number 
  FROM test 
  WHERE number = 3) AS "product" 
FROM test 
LIMIT 1;

You might aswell just JOIN the table onto itself.