explanation.txt

Another approach.

--Run the 3 queries to find the relevant data set to find the routes between 2 points

Example: ATQ to BLR

Query #1 : SELECT * FROM `flights` WHERE from_code = 'ATQ' and to_code = 'BLR'
returns direct flight       

    6845 ATQ BLR 1110 1415


Query #2: SELECT * FROM `flights` where from_code = 'ATQ' and to_code != 'BLR'
    6261	ATQ	BOM	1010	1245
    5926	ATQ	CCU	940	    1215
    2057	ATQ	DEL	1050	1205
    152	    ATQ	DEL	1545	1645
    286	    ATQ	DEL	1545	1645
    3274	ATQ	DEL	1615	1730
    2167	ATQ	DEL	2200	2315
    286	    ATQ	PNQ	1545	1935

This set is the flights from ATQ to some other point other than BLR. 

Query #3: SELECT f1.* from 
( SELECT * FROM `flights` where from_code = 'ATQ' and to_code != 'BLR' ) as tmp 
inner join flights f1 ON tmp.to_code = f1.from_code
where  f1.to_code = 'BLR'
GROUP BY f1.flight_no

       5321	    BOM	BLR	530	    720
        432	    BOM	BLR	815	    1010
        5354    BOM BLR 1030	1215
        283	    BOM	BLR	1620	1805
        199	    BOM	BLR	1855	2040
        128	    BOM	BLR	2010	2155
        406	    BOM	BLR	2125	2310
        6379    CCU BLR	450	    725
        825	    CCU	BLR	615	    900
        139	    CCU	BLR	720	    1005
        6143    CCU BLR 945	    1240
        434	    CCU	BLR	1145	1425
        6814    CCU BLR 1340	1625
        932	    CCU	BLR	1610	1855
        875	    CCU	BLR	1805	2035
        939	    CCU	BLR	1920	2205
        328	    CCU	BLR	2345	230
        2162	DEL	BLR	500	    740	
        2175	DEL	BLR	700	    945	
        2297	DEL	BLR	955	    1240
        2423	DEL	BLR	1400	1640																					
        819	    DEL	BLR	1410	1655																					
        2018	DEL	BLR	1515	1815																					
        2248	DEL	BLR	1620	1920																					
        2027	DEL	BLR	1745	2030																					
        2637	DEL	BLR	1905	2205																					
        2134	DEL	BLR	2110	10																					
        2429	DEL	BLR	2230	115																					
        954	    PNQ	BLR	900	    1025																					
        319	    PNQ	BLR	1600	1735																					
        103	    PNQ	BLR	1935	2115		

This a set of the connecting flights. 	With this set we could write the logic to get the fastest routes.