Question

非常感谢你花时间看看我的问题。我对mysql驱动的网络应用程序很陌生，我在查找查询时遇到了一些麻烦。

我有3张桌子：

事件：

event_id(INT) | event_fee(INT) | start_time(DATE_TIME) | stop_time(DATE_TIME)

表演者：

performer_id(INT) | performer_name(VARCHAR) | performer_fee(INT)

event_performers：

event_performers_id(INT) | event_id(INT) | performer_id(INT)

检索我使用的事件数据。

SELECT * 
FROM events 
JOIN event_performers
ON events.event_id = event_performers.event_id

我想运行一个测试查询，以确定是否有任何表演者同时对不同的事件采取行动。

我正在尝试检索所有表演者ID，所有事件ID并循环通过它们中的每一个来比较日期，但我得到堆叠做foreach循环并且不能真正让它工作

include('app/config.php');

function return_all_performers(){
include(PATH . '/core/model/db_connect.php');

try {
    $query_object = $db->query("
        SELECT performer_id 
        FROM performers
        ");
} catch (Exception $e){
    include_once(PATH . "/core/view/error.php");
    exit();
}

return $query_object->fetchAll(PDO::FETCH_COLUMN, 0);
}

function return_all_performer_events($performer_id){
include(PATH . '/core/model/db_connect.php');

try {
    $query_object = $db->prepare("
        SELECT * 
        FROM events 
        JOIN event_performers
        ON events.event_id = event_performers.event_id
        WHERE event_performers.performer_id = :performer_id
        ");
    $query_object->bindParam(':performer_id', $performer_id);
    $query_object->execute();
} catch (Exception $e){
    include_once(PATH . "/core/view/error.php");
    exit();
}

return $query_object->fetchAll(PDO::FETCH_ASSOC);   
}

$performers_ids = return_all_performers();
$overlaps = array();

foreach ($performers_ids as $performer_id) {
$performer_events = return_all_performer_events($performer_id);

foreach ($performer_events as $event => $value) {
    // Isolate Single event and compare it to others
    // TO DO
    // Check If times overlaps 
    /*
    foreach () {
        if(
            strtotime($event['start_time']) >= strtotime($isolated_event['start_time']) && 
            strtotime($event['start_time']) <= strtotime($isolated_event['stop_time'])
          ){
            return true;
        } 
        if(
            strtotime($event['stop_time']) >= strtotime($isolated_event['start_time']) && 
            strtotime($event['stop_time']) <= strtotime($isolated_event['stop_time'])
          ){
            $overlaps[] = $event;
        }
    }
    */
}
}

var_dump($overlaps);

非常感谢你的帮助，干杯

Answer 1

MySQL有一个between子句，将您的查询呈现为：

SELECT * 
FROM events 
JOIN event_performers
ON events.event_id = event_performers.event_id 
WHERE start_time BETWEEN ? OR ? AND stop_time BETWEEN ? and ?

希望有帮助...

Answer 2

您可以使用类似

的内容

SELECT 
    COUNT(*) AS amount_of_overlaps
FROM 
    events_table AS e1
JOIN (SELECT * FROM events_table) AS e2 ON (e2.id > e1.id)
WHERE 
    (e2.start_date BETWEEN e1.start_date AND e1.end_date)
OR
    (e2.end_date BETWEEN e1.start_date AND e1.end_date)

获取重叠事件的数量。你只需要为特定的人添加你的限制。

Answer 3

SELECT ep.performer_name, ep.performer_id, ep.performer_fee, e.event_id, e.event_fee,
e.start_time, e.stop_time, group_concat(e2.event_id SEPARATOR ',')
FROM events as e
JOIN event_performers ep ON e.event_id = ep.event_id
join events e2 on e2.event_id != e.event_id and 
     greatest(e2.start_time, e.start_time) < least(e2.stop_time,e.stop_time)
join  event_performers ep2 on ep2.event_id=e2.event_id and ep2.performer_id=ep.performer_id
group by ep.performer_name, ep.performer_id, ep.performer_fee, e.event_id, e.event_fee,
e.start_time, e.stop_time

这将返回每个有冲突的事件，并列出与之冲突的每个事件。它可以产生有趣的数据，因为如果A，B和C都冲突，你将获得3行。 1说A与B和C冲突，另一种说B与A和C冲突，有人说C与A和B冲突。也许你可以＆＃34;清理它＆＃34;但是你喜欢PHP，但这个数据可能是一个好的开始。

测试日期是否在单个查询中重叠

3 个答案: