Add new column to table and fill with the data of 2 other columns?

Question

I have a table with two columns: ColumnA and ColumnB .

How can I add a third column to my table that is ColumnA divided by ColumnB ?

I know this seems simple, but I have been unable to find the syntax.

Answer 1

You mean something like this:

SELECT ColumnA, 
       ColumnB, 
       (ColumnA / ColumnB) as ColumnC 
  FROM myTable

or to actually add a new column and fill it with the result of ColumnA divided by ColumnB like this:

ALTER TABLE `myTable` ADD `ColumnC` INT NOT NULL;
UPDATE `myTable` SET ColumnC = (ColumnA / ColumnB);