mysql显示时隙可用，时隙从表中忙 [英] mysql show time slots avaliable and time slots busy from table

问题描述

我有这个预订表格结构

|ID|timeBooked         | duration |
|2 |2013-05-09 11:10:00| 30       |
|1 |2013-05-09 14:40:00| 15       |
|AI| timespan          | int(4)   |

持续时间代表持续时间（分钟）。

duration represent the duration in minutes.

所以我想要的是返回这样的记录集，当我

so what i want is to return record set like this when i

查询可用的时间段在2013-05-09在00:00:00和23:00之间： 00

query available time slots in 2013-05-09 between 00:00:00 and 23:00:00

|free_from|Free_until| Free |
|00:00:00 |11:10:00  | 1
|11:10:00 |11:40:00  | 0
|11:40:00 |14:40:00  | 1
|14:40:00 |14:55:00  | 0
|14:55:00 |23:00:00  | 1

这可能是由mysql单独吗？

is this possible by mysql alone ?

推荐答案

好的，纯MySQL - 只要有人喜欢这些技巧。我需要一个变量，它被初始化为要显示的时间段的开始，像现在（）通常。

OK, pure MySQL - as long as one likes those tricks. I need a Variable which is initialized to the "Begin" of the periods to show, something like now() normally.

首先只是测试数据：

create table bookingEvents 
   (id int not null primary key auto_increment,
    timeBooked datetime, 
    duration int
   );


insert into bookingEvents values (null, '2013-05-13 13:22:00', 15);
insert into bookingEvents values (null, '2013-05-13 15:10:00', 45);
insert into bookingEvents values (null, '2013-05-13 19:55:00', 30);
insert into bookingEvents values (null, '2013-05-14 03:22:00', 15);
insert into bookingEvents values (null, '2013-05-14 08:19:00', 15);

然后初始化滑块：

set @timeSlider='2013-05-10 00:00:00';

然后选择：

select if (d.name = 'Free', @timeSlider, b.timeBooked) as free_from,
       if (d.name = 'Free', b.timeBooked, @timeSlider := b.timeBooked + interval b.duration minute) as free_until,
       d.name as Free
from (select 1 as place, 'Free' as name union select 2 as place, 'Booked' as name) d 
inner join bookingEvents b 
having free_from < free_until
order by b.timeBooked, d.place;

结果：

+---------------------+---------------------+--------+
| free_from           | free_until          | Free   |
+---------------------+---------------------+--------+
| 2013-05-10 00:00:00 | 2013-05-13 13:22:00 | Free   |
| 2013-05-13 13:22:00 | 2013-05-13 13:37:00 | Booked |
| 2013-05-13 13:37:00 | 2013-05-13 15:10:00 | Free   |
| 2013-05-13 15:10:00 | 2013-05-13 15:55:00 | Booked |
| 2013-05-13 15:55:00 | 2013-05-13 19:55:00 | Free   |
| 2013-05-13 19:55:00 | 2013-05-13 20:25:00 | Booked |
| 2013-05-13 20:25:00 | 2013-05-14 03:22:00 | Free   |
| 2013-05-14 03:22:00 | 2013-05-14 03:37:00 | Booked |
| 2013-05-14 03:37:00 | 2013-05-14 08:19:00 | Free   |
| 2013-05-14 08:19:00 | 2013-05-14 08:34:00 | Booked |
+---------------------+---------------------+--------+

如果你有一个给定的结束时间戳，那么你必须预设为@timeMaximum

If you have a given End-Timestamp, then you have to pre-set that as @timeMaximum

set @timeSlider='2013-05-10 00:00:00';
set @timeMaximum='2013-05-14 08:35:00';


select if (d.name = 'Free', @timeSlider, b.timeBooked) as free_from,
       if (d.name = 'Free', b.timeBooked, @timeSlider := b.timeBooked + interval b.duration minute) as free_until,
       d.name as Free
from (select 1 as place, 'Free' as name union select 2 as place, 'Booked' as name ) as d 
inner join bookingEvents b 
having free_from < free_until
union select @timeSlider as free_from, @timeMaximum as free_until, 'Free' as Free
from (select 1) as d
where @timeSlider < @timeMaximum

order by free_from, free_until
;

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