Joining tables to create a total sum of two seperate orders - sql

Question

I am trying to get the cost of each item over to a final table where it only shows the final ORDER_ID and the ORDER_TOTAL. I am having issues getting my two tables to join and am struggling with JOIN as a whole. These are the two tables that I am trying to join.
ORDER COST
CREATE TABLE `order cost` (
`ORDER_ID` int(10) NOT NULL,
`MENU_COST` double(5,2) NOT NULL,
`ORDER_COST` double(5,2) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
INSERT INTO `order cost` (`ORDER_ID`, `MENU_COST`, `ORDER_COST`) VALUES
(1, 7.00, 7.63),
(3, 8.00, 8.72),
(1, 13.00, 14.17),
(3, 25.00, 27.25);
ALTER TABLE `order cost`
ADD PRIMARY KEY (`ORDER_COST`),
ADD KEY `ORDER_ID` (`ORDER_ID`),
ADD KEY `MENU_COST` (`MENU_COST`);
ORDER TOTAL
CREATE TABLE `order total` (
`ORDER_ID` int(11) NOT NULL,
`ORDER_TOTAL` double(6,2) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
INSERT INTO `order total` (`ORDER_ID`, `ORDER_TOTAL`) VALUES
(1, 0.00),
(3, 0.00);
ALTER TABLE `order total`
ADD KEY `ORDER_ID` (`ORDER_ID`);
My join code attempt:
SELECT ORDER_ID,
SUM(MENU_COST) = ORDER_TOTAL
FROM `order cost`
INNER JOIN `order total`
GROUP BY ORDER_ID;
I have tried multiple other join ideas, and in the main order cost table I was able to get the SUMS(ORDER_COST) to create its own cell after I ran a
SELECT ORDER_ID, SUM(MENU_COST) FROM `order cost` GROUP BY ORDER_ID
But this creates its own table after the run, whereas I am looking to get the table to auto produce in the 'order total' based on changes to the database.

Answer 1

See comments above for my thoughts on not doing this. You'll have to run this query every time you make a change to the ordercost table:
UPDATE
ordertotal
SET
order_total = (
SELECT SUM(MENU_COST) FROM ordercost WHERE ORDER_ID = x GROUP BY ORDER_ID
)
WHERE order_id = x
There is no joining here.. you insert some new item to ordercost and then run the query to sync the table. On the whole it's a terrible idea. You should consider instead creating a VIEW and selecting from it when needed:
CREATE VIEW ordertotal AS
SELECT
ORDER_ID,
SUM(MENU_COST) as ORDER_TOTAL
FROM ordercost
GROUP BY ORDER_ID
It will behave like a table:
SELECT * FROM ordertotal where order_id = 3