Question

I’m trying to create google maps markers to show events, however I have the issue that sometimes the events take place at the same location – therefore markers overlap.

I thought if it would be possible to collapse results into one if more rows had the same venues.VENUE_LOCATION.

So, instead of producing an xml like this:

<marker lat="48.153938" lng="17.108459" venue="2" html="Event 1 - Jan 1" />
<marker lat="48.153938" lng="17.108459" venue="2" html="Event 2 - Jan 10" />
<marker lat="48.153938" lng="17.108459" venue="2" html="Event 3 - Jan 18" />
<marker lat="49.459843" lng="17.564821" venue="5" html="Event 55 - Jan 4" />
<marker lat="49.459843" lng="17.564821" venue="5" html="Event 70 - Jan 10" />

I would have one marker which would contain info for all of the markers in that location.

<marker lat="48.153938" lng="17.108459" venue="2" html="Event 1 - Jan 1<BR>Event 2 - Jan 10<BR>Event 3 - Jan 18" />
<marker lat="49.459843" lng="17.564821" venue="5" html="Event 55 - Jan 4<BR>Event 70 - Jan 10" />

Any idea how I could do that? Here is my current php code

    $query = "SELECT
    events.ID,
    events.EVENT_NAME,
    events.start_datetime,
    events.end_datetime,
    events.VENUE_LOCATION,
    venues.VENUE_NAME,
    venues.VENUE_LOCATION,
    venues.LAT,
    venues.LNG,
    GROUP_CONCAT(music_styles.MUSIC_STYLE_NAME) AS MUSIC_STYLE_NAME
    FROM events
    INNER JOIN venues 
    ON events.VENUE_LOCATION = venues.ID
    INNER JOIN events_music_styles
    ON events.ID = events_music_styles.event_id
    INNER JOIN music_styles
    ON events_music_styles.music_style_id = music_styles.id
    WHERE start_datetime >= '$phpFromDate'
    AND start_datetime <= '$phpToDate' 
";


$result = mysql_query($query);
if (!$result) {
  die('Invalid query: ' . mysql_error());
}



header("Content-type: text/xml");
echo '<markers>';

if(mysql_num_rows($result) > 0)
{
while ($row = @mysql_fetch_assoc($result))
{
  echo '<marker ';
  echo 'event_id="' . parseToXML($row['ID']) . '" ';
  echo 'lat="' . parseToXML($row['LAT']) . '" ';
  echo 'lng="' . parseToXML($row['LNG']) . '" ';
  echo 'venue="' . parseToXML($row['VENUE_LOCATION']) . '" ';
  echo '/>';
}
}
echo '</markers>';

Thanks!

Answer 1

Try to modify your SQL query in line with GROUP_CONCAT:

GROUP_CONCAT(music_styles.MUSIC_STYLE_NAME SEPARATOR '<br>') AS MUSIC_STYLE_NAME

Add also GROUP BY statement at the end of your query:

GROUP BY venues.LAT, venues.LNG

Then when you print marker tags out, add html attribute:

echo 'html="' . parseToXML($row['MUSIC_STYLE_NAME']) . '" ';

Desired code:

$query = "SELECT
    events.ID,
    events.EVENT_NAME,
    events.start_datetime,
    events.end_datetime,
    events.VENUE_LOCATION,
    venues.VENUE_NAME,
    venues.VENUE_LOCATION,
    venues.LAT,
    venues.LNG,
    GROUP_CONCAT(music_styles.MUSIC_STYLE_NAME SEPARATOR '<br/>') AS MUSIC_STYLE_NAME
    FROM events
    INNER JOIN venues 
    ON events.VENUE_LOCATION = venues.ID
    INNER JOIN events_music_styles
    ON events.ID = events_music_styles.event_id
    INNER JOIN music_styles
    ON events_music_styles.music_style_id = music_styles.id
    WHERE start_datetime >= '$phpFromDate'
    AND start_datetime <= '$phpToDate'
    GROUP BY venues.LAT, venues.LNG
";


$result = mysql_query($query);
if (!$result) {
  die('Invalid query: ' . mysql_error());
}



header("Content-type: text/xml");
echo '<markers>';

if(mysql_num_rows($result) > 0)
{
    while ($row = @mysql_fetch_assoc($result))
    {
      echo '<marker ';
      echo 'event_id="' . parseToXML($row['ID']) . '" ';
      echo 'lat="' . parseToXML($row['LAT']) . '" ';
      echo 'lng="' . parseToXML($row['LNG']) . '" ';
      echo 'venue="' . parseToXML($row['VENUE_LOCATION']) . '" ';
      echo 'html="' . parseToXML($row['MUSIC_STYLE_NAME']) . '" ';
      echo '/>';
    }
}
echo '</markers>';