# query to get producer and pharmaceutical company of product
# takes three arguments: first authnr of bloodproduct, second name of company, third name of producer
# default is none -> gets all
# argument as string: 'Name' or as like: '%Name%'
def query_comp_prod_product(authnr=None, company=None, producer=None):
    queryset = session.query(Medicinal_Product, Pharma_Company, Producer).\
    filter(Medicinal_Product.id == Producer.medicinal_product_id).\
    filter(Pharma_Company.id == Producer.pharma_comp_id).\
    filter(Pharma_Company.id == Medicinal_Product.pharma_comp_id)

    # only add the filter if it was passed in
    if authnr:
        queryset = queryset.filter(
            Medicinal_Product.authnr.like(authnr)
        )
    if company:
        queryset = queryset.filter(
            Pharma_Company.name.like(company)
        )
    if producer:
        queryset = queryset.filter(
            Producer.name.like(producer)
        )

    # printing statement of query
    for mp, c, p in queryset.all():
        print("Medicinal Product: %s; Name: %s" % (mp.authnr, mp.name))
        print("Pharmaceutical Company: %s" % c.name)
        print("Producer: %s" % p.name)
        print("-------------------------")