Either can be correct... or incorrect. You need to look at the full sentence and think about how relative clauses work. Then you'll know if you need a comma or not.

What are the differences in meaning at the sentences below? The builder, who erects very fine houses, will make a large profit. The builder who erects very fine houses will make a large profit.

I agree with Peachey. It would be much better if you wrote full sentences, so he could correct them. If you had done that, you could have got more help.