为什么SQL SELECT语句没有检索PHP日历的相关日期？

Question

I'm trying to build an events calendar in PHP and SQL based on an example by David Walsh. His example is quite old and uses functions like mysql_query which are deprecated so I have tried to modernise using PDO. So far I've managed to print out the calendar and am able to select different months and years. I've also successfully created a database connection. The table consists of an id (Auto incremented), title (varchar) and event_date(date). I've populated the table with a few events but I can't seem to retrieve them successfully. I've included the most relevant parts of the code at the top but I've copied the whole code over for context.

My query to the database

$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);

---

Result from my var_dump on $results

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'"
}

---

var_dump on $bookings says that my array is empty

 array(0) {
    }

---

Full code for context

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

Besides the LIKE issue

FetchAll get the entire set,so while wont work.Use foreach

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

Also in your while you use the assignment operator instead of the comparison ==