- rtrim: documentation ( source)
- str_repeat: documentation ( source)
- var_export: documentation ( source)
<?php
$event_types = array('ea', 'ec');
$type_count = count($event_types);
$evtypes = rtrim(str_repeat('?,', $type_count), ',');
$query = <<<QUERY
DELETE FROM
events
WHERE
evtype IN({$evtypes}) AND
cameraid = ? AND
endtime < ?
QUERY;
$params['types'] = str_repeat('s', $type_count) . 'si';
$params += $event_types;
$params[] = $deviceid;
$params[] = $oldest_actual_event_starttime;
var_export($params);