MySQl Subquery output with null data - mysql

Question

I have a MySQL database with vehicles, issued_fuel and mileage data (vs issued fuel) and want to get the following desired output.
Desired Output
I want to get results including above related data as follows :
+---------------+------------+------------+---------+----------+
| registered_no | issue_date | date | mileage | fuel_qty |
+---------------+------------+------------+---------+----------+
| SP KR-3503 | 2021-02-22 | null | null | 40 |
| SP KR-3503 | 2021-02-26 | null | null | 30 |
| null | 2021-03-03 | null | null | 40 |
| null | 2021-03-15 | null | null | 45 |
| SP KR-3503 | 2021-03-18 | null | null | 40 |
| null | 2021-03-25 | null | null | 45 |
| null | 2021-04-04 | null | null | 35 |
| SP KE-6794 | 2021-04-25 | 2021-04-25 | 150 | 40 |
+---------------+------------+------------+---------+----------+
Because the table "tbl_trip_details" includes only one mileage (150km) for vehicle_no "SP KE-6794 for the date 2021-04-25.
My tables as follows :
tbl_vehicle
+------------+---------------+--------+
| vehicle_id | registered_no | status |
+------------+---------------+--------+
| 1 | SP KR-3503 | 1 |
| 2 | SP KE-6794 | 1 |
+------------+---------------+--------+
tbl_trip_details
+---------+------------+------------+---------+--------+
| trip_id | vehicle_id | date | mileage | status |
+---------+------------+------------+---------+--------+
| 1 | 1 | 2021-04-25 | 125 | 1 |
| 2 | 1 | 2021-04-26 | 100 | 1 |
| 3 | 2 | 2021-04-25 | 150 | 1 |
+---------+------------+------------+---------+--------+
tbl_direct_fuel
+----------------+---------+------------+
| direct_fuel_id | vehicle | issue_date |
+----------------+---------+------------+
| 1 | 1 | 2021-02-22 |
| 2 | 1 | 2021-02-26 |
| 3 | 3 | 2021-03-03 |
| 4 | 3 | 2021-03-15 |
| 5 | 1 | 2021-03-18 |
| 6 | 3 | 2021-03-25 |
| 7 | 3 | 2021-04-04 |
| 8 | 2 | 2021-04-25 |
+----------------+---------+------------+
tbl_direct_fuel_details
+-----------------------------+----------------+------+----------+
| tbl_deirect_fuel_details_id | direct_fuel_id | item | fuel_qty |
+-----------------------------+----------------+------+----------+
| 1 | 1 | 1 | 40 |
| 2 | 2 | 1 | 30 |
| 3 | 3 | 1 | 40 |
| 4 | 4 | 1 | 45 |
| 5 | 5 | 1 | 40 |
| 6 | 6 | 1 | 45 |
| 7 | 7 | 1 | 35 |
| 8 | 8 | 1 | 40 |
+-----------------------------+----------------+------+----------+
I used the following query
select tv.registered_no, df.issue_date, td.date, td.mileage, df.fuel_qty
from tbl_trip_details trip
left join tbl_vehicle tv on tv.vehicle_id=trip.vehicle_id
join (select tbl_direct_fuel.direct_fuel_id, tbl_vehicle.registered_no, tbl_direct_fuel.vehicle, tbl_direct_fuel.issue_date, item, tbl_direct_fuel_details.fuel_qty, tbl_direct_fuel_details.fuel_price
from tbl_direct_fuel_details
left join tbl_direct_fuel on tbl_direct_fuel_details.direct_fuel_id = tbl_direct_fuel.direct_fuel_id
join tbl_vehicle on tbl_vehicle.vehicle_id = tbl_direct_fuel.vehicle
where tbl_direct_fuel.status=1
order by tbl_vehicle.registered_no
) AS df on df.vehicle = tv.vehicle_id
join (select tbl_trip_details.trip_id, tbl_vehicle.registered_no, tbl_trip_details.vehicle_id, tbl_trip_details.date, tbl_trip_details.mileage
from tbl_trip_details
left join tbl_vehicle on tbl_vehicle.vehicle_id = tbl_trip_details.vehicle_id
where tbl_trip_details.status=1
order by tbl_vehicle.registered_no) AS td on td.vehicle_id = tv.vehicle_id
Since the date & mileage are repeated for other records and didn't get the expected result. So the query outs the following output:
+---------------+------------+------------+---------+----------+
| registered_no | issue_date | date | mileage | fuel_qty |
+---------------+------------+------------+---------+----------+
| SP KR-3503 | 2021-02-22 | 2021-04-25 | 150 | 40 |
| SP KR-3503 | 2021-02-26 | 2021-04-25 | 150 | 30 |
| null | 2021-03-03 | 2021-04-25 | 150 | 40 |
| null | 2021-03-15 | 2021-04-25 | 150 | 45 |
| SP KR-3503 | 2021-03-18 | 2021-04-25 | 150 | 40 |
| null | 2021-03-25 | 2021-04-25 | 150 | 45 |
| null | 2021-04-04 | 2021-04-25 | 150 | 35 |
| SP KE-6794 | 2021-04-25 | 2021-04-25 | 150 | 40 |
+---------------+------------+------------+---------+----------+
What may be going wrong in my query ? Can anyone help ?

Answer 1

Try this query:
SELECT tv.registered_no, tdf.issue_date, ttd.date, ttd.mileage, tdfd.fuel_qty
FROM tbl_direct_fuel tdf
LEFT JOIN tbl_vehicle tv
ON tdf.vehicle=tv.vehicle_id
LEFT JOIN tbl_trip_details ttd
ON tdf.vehicle=ttd.vehicle_id
AND tdf.issue_date=ttd.date
LEFT JOIN tbl_direct_fuel_details tdfd
ON tdf.direct_fuel_id=tdfd.direct_fuel_id;
Demo fiddle
Rather than having two separate sub-queries, I try to directly get the result with a bunch of LEFT JOINs. From what I can see in the updated expected result, tbl_direct_fuel is enough to be the reference table for all the others. I's just a matter of figuring the correct ON condition.
Also, I mentioned about the missing tbl_direct_fuel.status and tbl_direct_fuel_details.fuel_price from the sample data. I'm not concerned about tbl_direct_fuel_details.fuel_price in particular because it wasn't included in the end SELECT result however, tbl_direct_fuel.status was being used in WHERE might have some impact. But after constructing the possible query, I assume that in this example, it's not required to include tbl_direct_fuel.status at all. Anyway, that's for you to figure out.