How to create automatic field completion in MySQL?

Question

MySQL

For example, there is a table:

model | color | x | y | z

And the second table:

model | x | y

We can say that the first table contains all the data, but the second requires only X and Y. How to make XY auto-complete when adding a model (exactly the same as in the first table).

Answer 1

trigger

Answer 2

Trigger ?

Answer 3

and what for to duplicate the data in the second table?