Not sure how to write this join

[aebstract]

I have 4 tables, 2 of the tables I have 1 row of returned information and another I will have 1+ rows and it'll be random.

 

Part: ID - returns 1 row

Product: partid - returns 1+ rows

Soitem: productnum, productid, soid

SO: ID - returns 1 row

 

What I need to do is pull some information from soitem where (soitem.soid = so.id) and (product.id = soitem.productid)

The thing is that I pull anywhere from 1 up towards 4 rows from product based on product.partid = part.id. I need to grab the 1 row from soitem where there is a similarity based on the results populated from soitem.soid. I hope this makes sense.