I need a multiple query method. Now let me tell you about my project I have 5 tables 1. Table Allergy_test_names fields test_id test_name 2 Table Allergy_test_results fields id test_id patient_id result 3. Table Diagonostic_names fields diagonostic_id diagonostic_name 4. Table Diagonostic_result fields id diagonostic_id diagonostic_test_result patient_id 5. Table Patients fields patient_id name surname I need to make a query which is below Assume that we have 5 patients Allergy Results 2 of them have olive allergy,mite allergy 1 of them has dog allergy 2 of them have mite allergy,cat allergy diagonostic Results 2 of them have high blood pressure and urticaria 2 of them have urticaria 1 of them has asthma A query sample How many patients who have both cat allergy and dog allergy and at the same time have asthma? Its answer is zero Another one How many patients who have asthma and at the same time have mite allergy? One patient... if the patient who is asthma has mite allergy otherwise the answer is zero. Now I have 2 multiple comboboxes Allergy Tests Diagonostics Test 1 Dia 1 Test 2 Dia 2 Test 3 Dia 3 . . . . . . How can i make such this queries. I tried to use split function but i faced out of range error