php - 为什么 SQL SELECT 语句不检索 PHP 日历的相关日期？

Question

我正在尝试根据 David Walsh 的示例使用 PHP 和 SQL 构建事件日历。他的例子已经很老了，并且使用了像 mysql_query 这样的函数，这些函数已经被弃用了，所以我尝试使用 PDO 进行现代化改造。到目前为止，我已经设法打印出日历并能够选择不同的月份和年份。我还成功地创建了一个数据库连接。该表由一个 id(自动递增)、title (varchar) 和 event_date(date) 组成。我已经用一些事件填充了表，但我似乎无法成功检索它们。我已经在顶部包含了代码中最相关的部分，但我已经复制了整个代码以供上下文引用。

我对数据库的查询

$events = array();
try {   $results = $db->query("SELECT title, DATE_FORMAT(event_date,'%Y-%m-%d') AS event_date FROM events WHERE event_date LIKE '$year-$month'");
        echo "<pre>";
        var_dump($results);
} catch (Exception $e) {
    echo "cannot get results!";
    exit;
}

$bookings = $results->fetchAll(PDO::FETCH_ASSOC);

while($row = $bookings) {
    $events[$row['event_date']][] = $row;
}

echo '<pre>';
var_dump($bookings);

---

来 self 在 $results 上的 var_dump 的结果

object(PDOStatement)#2 (1) {
  ["queryString"]=>
  string(105) "SELECT title, DATE_FORMAT(event_date,'%Y-%m-%d') AS event_date FROM events WHERE event_date LIKE '2014-1'"
}

---

$bookings 上的 var_dump 说我的数组是空的

 array(0) {
    }

---

上下文的完整代码

<?php 

require('database.php');

/* draws a calendar */
function draw_calendar($month,$year,$events = array()){

    /* draw table */
    $calendar = '<table cellpadding="0" cellspacing="0" class="calendar">';

    /* table headings */
    $headings = array('Sontag','Montag','Dienstag','Mittwoch','Donnerstag','Freitag','Samstag');
    $calendar.= '<tr class="calendar-row"><td class="calendar-day-head">'.implode('</td><td class="calendar-day-head">',$headings).'</td></tr>';

    /* days and weeks vars now ... */
    $running_day = date('w',mktime(0,0,0,$month,1,$year));
    $days_in_month = date('t',mktime(0,0,0,$month,1,$year));
    $days_in_this_week = 1;
    $day_counter = 0;
    $dates_array = array();

    /* row for week one */
    $calendar.= '<tr class="calendar-row">';

    /* print "blank" days until the first of the current week */
    for($x = 0; $x < $running_day; $x++):
        $calendar.= '<td class="calendar-day-np">&nbsp;</td>';
        $days_in_this_week++;
    endfor;

    /* keep going with days.... */
    for($list_day = 1; $list_day <= $days_in_month; $list_day++):
        $calendar.= '<td class="calendar-day"><div style="position:relative;height:100px;">';
            /* add in the day number */
            $calendar.= '<div class="day-number">'.$list_day.'</div>';

            $event_day = $year.'-'.$month.'-'.$list_day;
            if(isset($events[$event_day])) {
                foreach($events[$event_day] as $event) {
                    $calendar.= '<div class="event">'.$event['title'].'</div>';
                }
            }
            else {
                $calendar.= str_repeat('<p>&nbsp;</p>',2);
            }
        $calendar.= '</div></td>';
        if($running_day == 6):
            $calendar.= '</tr>';
            if(($day_counter+1) != $days_in_month):
                $calendar.= '<tr class="calendar-row">';
            endif;
            $running_day = -1;
            $days_in_this_week = 0;
        endif;
        $days_in_this_week++; $running_day++; $day_counter++;
    endfor;

    /* finish the rest of the days in the week */
    if($days_in_this_week < 8):
        for($x = 1; $x <= (8 - $days_in_this_week); $x++):
            $calendar.= '<td class="calendar-day-np">&nbsp;</td>';
        endfor;
    endif;

    /* final row */
    $calendar.= '</tr>';


    /* end the table */
    $calendar.= '</table>';

    /** DEBUG **/
    $calendar = str_replace('</td>','</td>'."\n",$calendar);
    $calendar = str_replace('</tr>','</tr>'."\n",$calendar);

    /* all done, return result */
    return $calendar;
}

function random_number() {
    srand(time());
    return (rand() % 7);
}

/* date settings */
$month = (int) ($_GET['month'] ? $_GET['month'] : date('m'));
$year = (int)  ($_GET['year'] ? $_GET['year'] : date('Y'));

/* select month control */
$select_month_control = '<select name="month" id="month">';
for($x = 1; $x <= 12; $x++) {
    $select_month_control.= '<option value="'.$x.'"'.($x != $month ? '' : ' selected="selected"').'>'.date('F',mktime(0,0,0,$x,1,$year)).'</option>';
}
$select_month_control.= '</select>';

/* select year control */
$year_range = 7;
$select_year_control = '<select name="year" id="year">';
for($x = ($year-floor($year_range/2)); $x <= ($year+floor($year_range/2)); $x++) {
    $select_year_control.= '<option value="'.$x.'"'.($x != $year ? '' : ' selected="selected"').'>'.$x.'</option>';
}
$select_year_control.= '</select>';

/* "next month" control */
$next_month_link = '<a href="?month='.($month != 12 ? $month + 1 : 1).'&year='.($month != 12 ? $year : $year + 1).'" class="control">Next Month &gt;&gt;</a>';

/* "previous month" control */
$previous_month_link = '<a href="?month='.($month != 1 ? $month - 1 : 12).'&year='.($month != 1 ? $year : $year - 1).'" class="control">&lt;&lt;    Previous Month</a>';


/* bringing the controls together */
$controls = '<form method="get">'.$select_month_control.$select_year_control.'&nbsp;<input type="submit" name="submit" class="btn btn-default" value="Go" />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'.$previous_month_link.'&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'.$next_month_link.' </form>';

/* get all events for the given month */
$events = array();
try {   $results = $db->query("SELECT title, DATE_FORMAT(event_date,'%Y-%m-%d') AS event_date FROM events WHERE event_date LIKE '$year-$month'");
        echo "<pre>";
        var_dump($results);
} catch (Exception $e) {
    echo "cannot get results!";
    exit;
}

$bookings = $results->fetchAll(PDO::FETCH_ASSOC);

while($row = $bookings) {
    $events[$row['event_date']][] = $row;
}

echo '<pre>';
var_dump($bookings);

echo '<h2 style="float:left; padding-right:30px;">'.date('F',mktime(0,0,0,$month,1,$year)).' '.$year.'</h2>';
echo '<div style="float:left;">'.$controls.'</div>';
echo '<div style="clear:both;"></div>';
echo draw_calendar($month,$year,$events);
echo '<br /><br />';

Answer 1

除了LIKE问题

FetchAll 获取整个集合，所以 while 不会工作。使用 foreach

foreach ($bookings as $row) {
    $events[$row['event_date']][] = $row;
}

同样在你使用赋值运算符而不是比较时 ==