How to convert a list in a cell into its own row in MySQL?

Question

I have this example of a table in MySQL

x        y

1        a, b, c
2        b, d, f

How do I extract each item in the y column into its own row?

I'm looking for something like this table below for example

x        y

1        a
1        b
1        c
2        b
2        d
2        f

Thanks!