Question

Mysql

mysql> select origin_id, destination_id,travel_date,departure_time,available_seats from `schedules` WHERE  travel_date = '2014-08-12' and origin_id = '134' and destination_id = '251'  ORDER BY STR_TO_DATE(departure_time,'%h:%i%p') limit 10;

+-----------+----------------+-------------+----------------+-----------------+
| origin_id | destination_id | travel_date | departure_time | available_seats |
+-----------+----------------+-------------+----------------+-----------------+
|       134 |            251 | 2014-08-12  | 06:00 AM       |              34 |
|       134 |            251 | 2014-08-12  | 07:00 AM       |              43 |
|       134 |            251 | 2014-08-12  | 07:30 AM       |               0 |
|       134 |            251 | 2014-08-12  | 07:30 AM       |              34 |
|       134 |            251 | 2014-08-12  | 08:30 AM       |               0 |
|       134 |            251 | 2014-08-12  | 08:30 AM       |              29 |
|       134 |            251 | 2014-08-12  | 10:15 AM       |              36 |
|       134 |            251 | 2014-08-12  | 10:15 AM       |               0 |
|       134 |            251 | 2014-08-12  | 10:30 AM       |              29 |
|       134 |            251 | 2014-08-12  | 11:00 AM       |               0 |
+-----------+----------------+-------------+----------------+-----------------+
10 rows in set (0.04 sec)

第一个查询：在此查询中，我按出发时间发出订单。但是我希望所有记录中的available_seats 0都应该以departure_time的顺序排在最后。

必填项 ...... ??

   +-----------+----------------+-------------+----------------+-----------------+
    | origin_id | destination_id | travel_date | departure_time | available_seats |
    +-----------+----------------+-------------+----------------+-----------------+
    |       134 |            251 | 2014-08-12  | 06:00 AM       |              34 |
    |       134 |            251 | 2014-08-12  | 07:00 AM       |              43 |
    |       134 |            251 | 2014-08-12  | 07:30 AM       |              34 |
    |       134 |            251 | 2014-08-12  | 08:30 AM       |              29 |
    |       134 |            251 | 2014-08-12  | 10:15 AM       |              36 |
    |       134 |            251 | 2014-08-12  | 10:30 AM       |              29 |
    |       134 |            251 | 2014-08-12  | 07:30 AM       |               0 |
    |       134 |            251 | 2014-08-12  | 08:30 AM       |               0 |
    |       134 |            251 | 2014-08-12  | 10:15 AM       |               0 |
    |       134 |            251 | 2014-08-12  | 11:00 AM       |               0 |
    +-----------+----------------+-------------+----------------+-----------------+

是否可以使用mysql查询。或与其他方式???

Answer 1

您可以先使用where和order by语句对可用席位的非零值的出发时间进行排序，然后可以按顺序应用union，以按时间递增的顺序附加零柱状可用席位。代码如下：

select origin_id, destination_id,travel_date,departure_time,available_seats from `schedules` WHERE  travel_date = '2014-08-12' and origin_id = '134' and destination_id = '251'  ORDER BY STR_TO_DATE(departure_time,'%h:%i%p') limit 10 and available_seats <> 0

union

select origin_id, destination_id,travel_date,departure_time,available_seats from `schedules` WHERE  travel_date = '2014-08-12' and origin_id = '134' and destination_id = '251'  ORDER BY STR_TO_DATE(departure_time,'%h:%i%p') limit 10 where available_seats = 0;

简而言之，添加available_seats＆lt;＆gt;在联盟的第一部分0，然后在union之后应用available_seats = 0。

Answer 2

使用CASE子句：

ORDER BY CASE 
    WHEN available_seats=0 THEN '99:99' 
    else STR_TO_DATE(departure_time,'%h:%i%p') END

请注意，您指定了LIMIT子句，这可能会产生意外结果。

此外，如果您同时拥有AM和PM时间，则按时间顺序对AM / PM进行排序将不会按时间顺序排序。

如何使用条件在mysql中按两列对表进行排序？

2 个答案: