Checking if value already exists in two different sheets

I need a macro that works over different tables like this (lets call tem x y z):

  x
------------
a 0 
b 1  
c 2  

  y
------------
a 3 
b 1  
c 2 

  z
------------
a 3 
b 1  
c 2 

and I need a results table like this (table is already made, just fill):

  x  y  z
------------
a 0  3  2
b 1  0  3
c 2  2  1

What do I need? When scaing tables, "a b and c" will be repeated. I need to print every result without creating in that column extra set of data.

I don't want:

  x  y  z
------------
a 0    
b 1 
c 2     
a    3  
b    0  
c    1  
a       1
b       3
c       1

How can I achieve this?