SQL Query to get count of cycles if it matches value of column in consecutive rows

Question

I have table named vehicledata which consists 3 columns: id, Veh No, and Veh Mode.

My data looks like this:

Answer 1

@Pradeep - The logic to build this query will be to check only rows where vehicle is currently in drive mode and he was IDLE before that ROW. You don't have to worry about IDLE modes and also the continuous DRIVE modes. You only need to check the rows where a vehicle has transitioned from IDLE to DRIVE. I have used a case statement and a LAG windows function to mark only these records as 1 and everything else as 0. And then I just took a sum of this column for each vehicle.

------------------------
WITH vehicles(id , Veh_No,  Veh_Mode) AS
( 
SELECT 1 ,  'KA03-003',   'IDLE'  UNION
SELECT 2 ,  'KA03-003',   'IDLE'  UNION
SELECT 3 ,  'KA03-003',   'IDLE'  UNION
SELECT 4 ,  'KA03-003',   'DRIVE' UNION
SELECT 5 ,  'KA03-003',   'DRIVE' UNION
SELECT 6 ,  'KA03-003',   'DRIVE' UNION
SELECT 7 ,  'KA03-003',   'DRIVE' UNION
SELECT 8 ,  'KA03-003',   'DRIVE' UNION
SELECT 9 ,  'KA03-003',   'IDLE'  UNION
SELECT 10,  'KA03-003',   'IDLE'  UNION
SELECT 11,  'KA03-003',   'IDLE'  UNION
SELECT 12,  'KA03-003',   'DRIVE' UNION
SELECT 13,  'KA03-003',   'DRIVE' UNION
SELECT 14,  'KA03-003',   'DRIVE' UNION
SELECT 15,  'KA03-003',   'DRIVE' UNION
SELECT 16,  'KA05-005',   'IDLE'  UNION
SELECT 17,  'KA05-005',   'IDLE'  UNION
SELECT 18,  'KA05-005',   'IDLE'  UNION
SELECT 19,  'KA05-005',   'DRIVE' UNION
SELECT 20,  'KA05-005',   'DRIVE' UNION
SELECT 21,  'KA05-005',   'DRIVE' UNION
SELECT 22,  'KA05-005',   'DRIVE' UNION
SELECT 23,  'KA05-005',   'DRIVE' UNION
SELECT 24,  'KA05-005',   'IDLE'  UNION
SELECT 25,  'KA05-005',   'IDLE'  UNION
SELECT 26,  'KA05-005',   'IDLE'  UNION
SELECT 27,  'KA05-005',   'DRIVE' UNION
SELECT 28,  'KA05-005',   'DRIVE' UNION
SELECT 29,  'KA05-005',   'DRIVE' UNION
SELECT 30,  'KA05-005',   'DRIVE'
)

SELECT veh_no, SUM(count_drive_cycle) AS drive_cycles
FROM (SELECT *,
      CASE WHEN Veh_Mode = 'DRIVE'
            AND LAG(veh_mode,1,'DRIVE') OVER (PARTITION BY Veh_No ORDER BY id) = 'IDLE'   -- check if prev mode is IDLE
           THEN 1
           ELSE 0 END AS count_drive_cycle
      FROM vehicles
     ) A
GROUP BY veh_no