SELECT district.name
FROM district
JOIN quartier ON district.quartier= quartier.district
WHERE count (ST_Intersects (district.geom, quartier.geom))

SELECT district.name, count(quartier.id)
    FROM districts, quartier
    WHERE st_intersects(districts.geom, quartier.geom)
    GROUP BY district.name
    HAVING count(quartier.id) = 3