Mysql 按两列分别排序

Question

我想对查询结果进行排序，以便 2 列按升序排序。两列都可以包含值 0 或 NULL，然后在排序时忽略这些值。

我不知道我是否表达清楚了。

这是我的询问：

SELECT tripad_order, tourad_order
FROM(
    SELECT tripad_order, tourad_order
    FROM tripdetails 
    LEFT JOIN tripaddresses ON tripaddresses.trip_id = tripdetails.trip_id
    LEFT JOIN touraddresses ON touraddresses.tripad_id = tripaddresses.tripad_id AND touraddresses.tour_id = tripdetails.tour_id
    WHERE tripde_id = 39780

    UNION ALL

    SELECT tripad_order, tourad_order
    FROM tripdetails 
    LEFT JOIN touraddresses ON touraddresses.tour_id = tripdetails.tour_id 
    LEFT JOIN tripaddresses ON tripaddresses.tripad_id = touraddresses.tripad_id AND tripaddresses.trip_id IN (0,tripdetails.trip_id)
    WHERE tripde_id = 39780 AND tripad_type IS NOT NULL
) t
GROUP BY tripad_id
ORDER BY tourad_order

这是结果

tripad_订单	tourad_order
2	空
0	1
1	2
3	4
0	5

这是想要的：结果 tripad_order 和tourad_order 都应该按升序排列，忽略0和NULL

tripad_订单	tourad_order
0	1
1	2
2	空
3	4
0	5

Answer 1

SELECT tripad_order, tourad_order
FROM (
    SELECT tripad_order, tourad_order
    FROM tripdetails 
    LEFT JOIN tripaddresses ON tripaddresses.trip_id = tripdetails.trip_id
    LEFT JOIN touraddresses ON touraddresses.tripad_id = 
     tripaddresses.tripad_id AND touraddresses.tour_id = tripdetails.tour_id
    WHERE tripde_id = 39780

    UNION ALL

    SELECT tripad_order, tourad_order
    FROM tripdetails 
    LEFT JOIN touraddresses ON touraddresses.tour_id = tripdetails.tour_id 
    LEFT JOIN tripaddresses ON tripaddresses.tripad_id = 
    touraddresses.tripad_id AND tripaddresses.trip_id IN (0, 
     tripdetails.trip_id)
    WHERE tripde_id = 39780 AND tripad_type IS NOT NULL
) t
GROUP BY tripad_order, tourad_order
ORDER BY 
    CASE WHEN tripad_order = 0 THEN NULL ELSE tripad_order END,
    CASE WHEN tourad_order IS NULL THEN 1 ELSE 0 END, 
    tourad_order;

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