PHP PDO中的多个选择

Question

如何在PDO中的同一查询中运行多个select语句？我在phpMyAdmin中运行它时，我的SQL语句工作正常吗？代码如下：

$sql = 'SELECT DISTINCT apartment.apartmentName, 
                        apartment.apartmentID
        FROM apartment_information apartment, 
             apartment_ratings ratings, 
             apartment_floorplans floorplan, 
             user_user user 
        WHERE user.preferred_zip = :zip
          AND floorplan.apartmentID = apartment.apartmentID
          AND floorplan.apartmentID = (SELECT apartmentID 
                                        FROM apartment_floorplans 
                                        WHERE monthlyPrice < :monthlyPrice 
                                              AND apartmentNumBedrooms = :apartmentNumBedrooms
                                              AND apartmentNumBathrooms = :apartmentNumBathrooms)';

        try{
            echo $sql;
            $stmt = $this->_db->prepare($sql);
            $stmt->bindParam(":zip", $this->_zip, PDO::PARAM_STR);
            $stmt->bindParam(":monthlyPrice", $this->_apartmentFloorPlans['Price'], PDO::PARAM_STR);
            $stmt->bindParam(":apartmentNumBedrooms", $this->_apartmentFloorPlans['Bedrooms'], PDO::PARAM_STR);
            $stmt->bindParam(":apartmentNumBathrooms", $this->_apartmentFloorPlans['Bathrooms'], PDO::PARAM_STR);

        }

            $stmt->execute();