--улицы, продолжительность которых ограничивается только одним районом
SELECT S1.NameStreet
FROM Street S1
WHERE NOT EXISTS (
SELECT *
FROM Street S2
WHERE S1.NameStreet=S2.NameStreet
  AND S1.id_District<>S2.id_District
  AND S1.NameCity=S2.NameCity)

--районы, в которых не продаютс€ однокомнатные квартиры (не продаютс€ в районе 6-severny)
SELECT DISTINCT House.id_District, District.NameDistrict
FROM House, District
WHERE District.id_District=House.id_District
  AND House.id_District NOT IN (
    SELECT DISTINCT House.id_District
    FROM Apartment, House
    WHERE House.id_House=Apartment.id_House
      AND Apartment.rooms IN (1))

--районы, в которых продаются квартиры всех строительных серий
SELECT DISTINCT S.NameDistrict
FROM (
    SELECT DISTINCT District.NameDistrict, House.seriesHouse
    FROM House, District
    WHERE District.id_District=House.id_District)S
    WHERE NOT EXISTS (
                SELECT * FROM (
                        SELECT DISTINCT House.seriesHouse
                        FROM House
                        WHERE House.seriesHouse IN ('P-44','P-44T','I-521A'))Serii
                WHERE NOT EXISTS (SELECT *
                          FROM (
                            SELECT DISTINCT District.NameDistrict, House.seriesHouse
                            FROM House, District
                          WHERE District.id_District=House.id_District)S1
WHERE S.NameDistrict=S1.NameDistrict
  AND S1.seriesHouse=Serii.seriesHouse))