通过单个查询获取多个表列的总和

Question

I have a main table hotel and its sub tables hotel_food , hotel_extras , hotel_room with the reference Id hotel ,

And now I want to get the sum of price column in each table (hotel_food, hotel_extras, hotel_room) for each hotels.

Now I am using like this

$result = $db->query("SELECT id FROM hotel WHERE id = '.$hotel.'");
if($row = $result->fetch_array(MYSQLI_ASSOC)) {
   $food_result = $db->query("SELECT sum(price) FROM hotel_food WHERE hotel_id = '".$row['id']."'");
   $room_result = $db->query("SELECT sum(price) FROM hotel_room WHERE hotel_id = '".$row['id']."'");
   $extras_result = $db->query("SELECT sum(price) FROM hotel_extras WHERE hotel_id = '".$row['id']."'");
}

Is there any way to get the sum of all tables prices like totalFoodPrice, totalRoomPrice,totalExtrasPrice with a single query

Thanks in advance

Answer 1

SELECT * FROM
(
 SELECT sum(price) AS totalFoodPrice FROM hotel_food WHERE hotel_id = 1,
 SELECT sum(price) AS totalRoomPrice FROM hotel_room WHERE hotel_id = 1,
 SELECT sum(price) AS totalExtrasPrice FROM hotel_extras WHERE hotel_id = 1
) temp

Answer 2

You can make use of the subqueries like this :

$result = $db->query("SELECT id, 
   (SELECT sum(price) FROM hotel_food WHERE hotel_id = h.id) TotalFoodPrice,
   (SELECT sum(price) FROM hotel_room WHERE hotel_id = h.id) TotalRoomPrice,
   (SELECT sum(price) FROM hotel_extras WHERE hotel_id = h.id) TotalExtraPrice
FROM hotel h WHERE id = '.$hotel.'");