MySQL: Computed Column

Question

I\'m just started using SQL and ran into a problem.

In my database, I presently have two tables, Cinemas and Theatres. I\'m trying to create a column \"# of Theatre

Answer 1

In mysql you if you want an actual column you would

• create it as any column
• make sure it is consistent by creating a trigger on theatre table that will update the column ever time a row is added or deleted