MySQL Extract multiple values from a XML column and put them into separated columns

Question

With the following code

SELECT EXTRACTVALUE('<a><b>x</b><b>y</b><b>z</b></a>', '//b') as 'values'

I got this:

values
x y z

But I want this:

value_b0 value_b1 value_b2
   x        y        z

How?