SQL double SELECT on the same field (mysql or sqlite3)

Answer 1

Using GROUP BY/COUNTING:

  SELECT t.bus_line_id,
         t.bus_line_type,
         t.bus_line_number
    FROM BUS_LINE t
    JOIN LINK_BUS_NEIGBOURHOOD lbn ON lbn.bus_line_id = t.bus_line_id
    JOIN LINK_NEIGHBOURHOOD_STREET lns ON lns.neighbourhood_id_ns = lbn.neighbourhood_id_ns
    JOIN STREET s ON s.street_id = lns.street_id
   WHERE s.street_id IN (12, 14)
GROUP BY t.bus_line_id,
         t.bus_line_type,
         t.bus_line_number,
         s.street_id
  HAVING COUNT(DISTINCT s.street_id) = 2

Using JOINs:

SELECT t.bus_line_id,
       t.bus_line_type,
       t.bus_line_number
  FROM BUS_LINE t
  JOIN LINK_BUS_NEIGBOURHOOD lbn ON lbn.bus_line_id = t.bus_line_id
  JOIN LINK_NEIGHBOURHOOD_STREET lns ON lns.neighbourhood_id_ns = lbn.neighbourhood_id_ns
  JOIN STREET s ON s.street_id = lns.street_id
               AND s.steet_id = 12
  JOIN STREET s2 ON s2.street_id = lns.street_id
                AND s2.steet_id = 14

Answer 2

Assuming you want three separate records in your sample result set and assuming that all the "neighborhood_id" columns are FKs back to the neighborhood table, try:

SELECT * 
  FROM bus_line 
 WHERE EXISTS (SELECT * 
                 FROM neighborhood N 
           INNER JOIN link_neighborhood_street S ON N.neighborhood_id = S.neighborhood_id_ns 
                WHERE S.street_id = 12) 
  AND EXISTS (SELECT * 
                FROM neighborhood N 
          INNER JOIN link_neighborhood_street S ON N.neighborhood_id = S.neighborhood_id_ns 
               WHERE S.street_id = 14);