mysql查询多个外键

Question

mysql表格如下


    +------------+----------------+----------------+
    | booking_id | boarding_point | dropping_point |
    +------------+----------------+----------------+
    |          1 |              2 |              4 |
    |          2 |              1 |              2 |
    +------------+----------------+----------------+


    +-------------+---------------+
    | location_id | location_name |
    +-------------+---------------+
    |           1 | chennai       |
    |           2 | coimbatore    |
    |           3 | tiruppur      |
    |           4 | erode         |
    |           5 | salem         |
    +-------------+---------------+

boarding_point 和 dropping_point 是 location_id 的外键。现在我希望 select 查询显示为


    +------------+----------------+----------------+
    | booking_id | boarding_point | dropping_point |
    +------------+----------------+----------------+
    |          1 |     coimbatore |          erode |
    |          2 |        chennai |     coimbatore |
    +------------+----------------+----------------+

任何人都可以建议我像上面那样显示的查询。

Answer 1

加入预订table两次到地点table:

SELECT
    b.booking_id,
    t1.location_name,
    t2.location_name
FROM booking b
INNER JOIN location t1
    ON b.boarding_point = t1.location_id
INNER JOIN location t2
    ON b.dropping_point = t2.location_id;

mysql查询多个外键

mysql query for multiple foreign keys

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