检查两次是否重叠

Question

我想看看我从数据库中读取的时间是否与用户提供的时间重叠.

我的数据库看起来像这样:

-----------------------------------------------
|organiser|meeting_start|meeting_end|boardroom|
-----------------------------------------------
| John Doe| 1340193600  | 1340195400| big     |
-----------------------------------------------

我的代码看起来像这样:

date_default_timezone_set('Africa/Johannesburg');
$from = strtotime($_GET['meeting_date'] . ' ' . $_GET['meeting_start']);
$to = strtotime($_GET['meeting_date'] . ' ' . $_GET['meeting_end']);
$another_meeting = false;
$meeting_date = strtotime($_GET['meeting_date']);
$meeting_next = $meeting_date + 86400;

$result = mysql_query("SELECT meeting_start, meeting_end FROM admin_boardroom_booking WHERE boardroom = '" . $_GET['boardroom'] . "' AND meeting_start >= '" . $meeting_date . "' AND meeting_end < '" . $meeting_next . "'")or die(mysql_error());
while($row = mysql_fetch_array($result)) {
    $from_compare = $row['meeting_start'];
    $to_compare = $row['meeting_end'];

    $intersect = min($to, $to_compare) - max($from, $from_compare);
    if ( $intersect < 0 )
        $intersect = 0;

    $overlap = $intersect / 3600;
    if ( $overlap <= 0 ) {
        $another_meeting = true;
        break;
    }
}

if ($another_meeting)
    echo 'ERROR';

如果我故意键入两个重叠时间,它不会回显错误.我究竟做错了什么？

Answer 1

当且仅当这些条件中的至少一个成立时,两个时间段P1和P2重叠:

1. P1在P2(P2.from <= P1.from <= P2.to)的开始和结束之间开始
2. P2在P1(P1.from <= P2.from <= P1.to)的开始和结束之间开始

这将捕获部分重叠的时期以及完全覆盖另一个时期的时期.如果它们重叠,则其中一个时段必须始终在另一个时段内开始(或结束).

所以$another_meeting定义为:

$another_meeting = ($from >= $from_compare && $from <= $to_compare) ||
                   ($from_compare >= $from && $from_compare <= $to);

<如果一个事件可以在与另一个事件完全相同的时间开始,您可能希望将边界情况更改为严格检查.

Answer 2

只是在做类似的事情......但只是随着时间......

$startTime = strtotime("7:00");
$endTime   = strtotime("10:30");

$chkStartTime = strtotime("10:00");
$chkEndTime   = strtotime("12:10");

if($chkStartTime > $startTime && $chkEndTime < $endTime)
{
    // Check time is in between start and end time
    echo "1 Time is in between start and end time";
}
elseif(($chkStartTime > $startTime && $chkStartTime < $endTime) || ($chkEndTime > $startTime && $chkEndTime < $endTime))
{
    // Check start or end time is in between start and end time
    echo "2 ChK start or end Time is in between start and end time";
}
elseif($chkStartTime==$startTime || $chkEndTime==$endTime)
{
    // Check start or end time is at the border of start and end time
    echo "3 ChK start or end Time is at the border of start and end time";
}
elseif($startTime > $chkStartTime && $endTime < $chkEndTime)
{
    // start and end time is in between  the check start and end time.
    echo "4 start and end Time is overlapping  chk start and end time";
}