A function to add date clauses Zend_Db_Select filtering by day/month/year

add_date_filter_clause.php

 /**
     * Add clauses for date values chosen to select
     * 
     * @param Zend_Db_Select $oSelect
     * @param integer        $day
     * @param integer        $month
     * @param integer        $year
     * 
     * @return Zend_Db_Select
     */
    public function _addDateClauses($oSelect, $day, $month, $year)    
    {
        // If all three are set then we need to get events running over a specific date
        if ($day && $month && $year) {
            
            $date = sprintf("%d-%02d-%02d 00:00:00",$year, $month, $day);
            $oSelect->where('? BETWEEN start_date AND d.end_date', $date);
            
        }else if (!$day && $month && $year){
            
            // If the day is not set then assume we want all events from the month provided
            $start_date = sprintf("%d-%02d-%02d 00:00:00",$year, $month, 1);
            
            $end_date = new Zend_Date($start_date);
            $end_date->add(1, Zend_Date::MONTH);
            
            $condition = sprintf(
                '(start_date BETWEEN "%1$s" AND "%2$s" || d.end_date BETWEEN "%1$s" AND "%2$s")',
                $start_date,
                $end_date->toString('yyyy-MM-dd HH:mm:s')
            );
            
            $oSelect->where($condition);
            
        }else{
            
            // Assume we want events that are in future - this is the default
            $date = date('Y-m-d 00:00:00');
            $oSelect->where('? > start_date && ? < d.end_date', $date);
            
        }        
        
        return $oSelect;
    }