MySQl 带有空数据的子查询输出
MySQl Subquery output with null data
我有一个 MySQL 数据库，其中包含车辆、issued_fuel 和里程数据（与发出的燃料相比），并希望获得以下所需的输出。
期望的输出
我想得到包含以上相关数据的结果如下：
+---------------+------------+------------+---------+----------+
| 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 |
+---------------+------------+------------+---------+----------+
因为table“tbl_trip_details”只包括 vehicle_no“SP KE-6794 日期 2021-04-25 的一英里（150 公里）。
我的 table 如下：
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_详情
+-----------------------------+----------------+------+----------+
| 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 |
+-----------------------------+----------------+------+----------+
我使用了以下查询
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
由于其他记录的日期和里程重复，没有得到预期的结果。所以查询出以下输出：
+---------------+------------+------------+---------+----------+
| 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 |
+---------------+------------+------------+---------+----------+
我的查询可能出了什么问题？有人可以帮忙吗？
试试这个查询：
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;
我没有使用两个单独的子查询，而是尝试使用一堆 LEFT JOIN 直接获得结果。从我在更新后的预期结果中看到的，tbl_direct_fuel 足以作为所有其他人的参考 table。我只是想找出正确的 ON 条件。
此外，我提到了示例数据中缺少的 tbl_direct_fuel.status 和 tbl_direct_fuel_details.fuel_price。我并不特别担心 tbl_direct_fuel_details.fuel_price，因为它没有包含在最后的 SELECT 结果中，但是 tbl_direct_fuel.status 在 WHERE 中使用可能会产生一些影响。但是在构建可能的查询之后，我假设在这个例子中，根本不需要包含 tbl_direct_fuel.status 。不管怎样，那是你自己想出来的。
我有一个 MySQL 数据库，其中包含车辆、issued_fuel 和里程数据（与发出的燃料相比），并希望获得以下所需的输出。
期望的输出
我想得到包含以上相关数据的结果如下：
+---------------+------------+------------+---------+----------+
| 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 |
+---------------+------------+------------+---------+----------+
因为table“tbl_trip_details”只包括 vehicle_no“SP KE-6794 日期 2021-04-25 的一英里（150 公里）。 我的 table 如下：
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_详情
+-----------------------------+----------------+------+----------+
| 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 |
+-----------------------------+----------------+------+----------+
我使用了以下查询
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
由于其他记录的日期和里程重复，没有得到预期的结果。所以查询出以下输出：
+---------------+------------+------------+---------+----------+
| 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 |
+---------------+------------+------------+---------+----------+
我的查询可能出了什么问题？有人可以帮忙吗？
试试这个查询：
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;
我没有使用两个单独的子查询，而是尝试使用一堆 LEFT JOIN 直接获得结果。从我在更新后的预期结果中看到的，tbl_direct_fuel 足以作为所有其他人的参考 table。我只是想找出正确的 ON 条件。
此外，我提到了示例数据中缺少的 tbl_direct_fuel.status 和 tbl_direct_fuel_details.fuel_price。我并不特别担心 tbl_direct_fuel_details.fuel_price，因为它没有包含在最后的 SELECT 结果中，但是 tbl_direct_fuel.status 在 WHERE 中使用可能会产生一些影响。但是在构建可能的查询之后，我假设在这个例子中，根本不需要包含 tbl_direct_fuel.status 。不管怎样，那是你自己想出来的。