Mysql join tables Randomly

I have two tables. (say TableA and TableB)

TableA have 10 rows and TableB have 50 rows.

I want each row in TableA should be joined with X number of rows from TableB randomly, so that i get 500 unique results

For example if TableA has rows (a,b,c) and TableB have rows (p,q,r,s,t,u) and X=2 ,then expected result is:

a-p
a-q
b-r
b-s
c-t
c-u

This joining should be random