how to divide big inner join to sub inner joins and combine

I am trying to do inner join of tables, A and B. Both the tables are very BIG. Due to this memory constraint my join is failing. Proposed Solution:

1. Divide table B in 5 parts.
2. perform table A inner join with all 5 parts of table B seperately.
3. Now union all the 5 inner join results.

Does this approach seem correct OR am I missing something?

Please help me with this?