How to select a column to compare two values in it with AND
If I understand right you need select records that equals two values. You can look this query like exsample:

SELECT firm_property.firm_id, firm.title
FROM  firm_property INNER JOIN
   firm ON firm_property.firm_id = firm.id
WHERE  (firm_property.property_id IN ('PKR3344', 'WWF1155'))
GROUP BY firm_property.firm_id, firm.title
HAVING  (COUNT(*) = 2)


If you write your tables and treir data we can make the better answer query.