MySQL Query with Multiple COALESCE и JOIN возвращает ошибку

Question

У меня запрос MySQL с использованием нескольких COALESCE и JOIN. Моя цель - получить значение из другой таблицы, если оно нулевое или отсутствует в первой таблице.

Моя проблема в том, что если он охватывает большие данные, он выдает ошибку: Fatal Error: Allowed memory size of ###### bytes exhausted. (tried to allocate...)

Я пытался создать таблицу представления, но даже мой PhpMyAdmin не может ее обработать.

Вот запрос:

SELECT COALESCE(i.`LastSyncDate`, o.`DateCreated`) AS TransDate,
                    COALESCE(CASE WHEN co.`Agent_ID` IS NOT NULL THEN UPPER(CONCAT(wp_agent.`first_name`, ' ', wp_agent.`last_name`)) ELSE '' END, CASE WHEN o.`StaffID` IS NOT NULL THEN UPPER(CONCAT(oss_agent.`first_name`, ' ', oss_agent.`last_name`)) ELSE '' END) AS AgentName,
                    COALESCE(UPPER(CONCAT(co.`LastName`, ' ', co.`FirstName`)), UPPER(CONCAT(u.`last_name`, ' ', u.`first_name`))) AS CustomerName,
                    COALESCE(UPPER(bb.`Name`), UPPER(bbb.`Name`)) AS ProductCode,
                    COALESCE(i.`Size`, o.`BoxSize`) AS dimension,
                    COALESCE(UPPER(r.`RouteCode`), UPPER(rr.`RouteCode`)) AS Destination,
                    COALESCE(UPPER(ocy.`Name`), UPPER(cy.`Name`)) AS City,
                    COALESCE(UPPER(op.`Name`), UPPER(p.`Name`)) AS Province,
                    COALESCE(UPPER(i.`BoxNumber`), UPPER(o.`BoxNumber`)) AS InvoiceNumber, 
                    COALESCE((i.`Price` + i.`Tax`), o.`Price`) AS GrossAmount, 
                    COALESCE((i.`AgentCom_AddPrice` + (i.`AgentCom_Factor` * i.`Price`)), 0) AS Commission, 
                    COALESCE(i.`discount_price`, o.`promocode_discount`, 0) AS Discount,
                    COALESCE((i.`Price` - i.`discount_price` - (i.`AgentCom_AddPrice` + (i.`AgentCom_Factor` * i.`Price`))), (o.`Price` - o.`promocode_discount`), 0) AS NetAmount  
                    FROM `cq_order_items` i LEFT OUTER JOIN `orders` o ON i.`BoxNumber` = o.`BoxNumber`
                    LEFT JOIN `cq_orders` co ON i.`OrderID` = co.`ID`
                    LEFT JOIN `users` u ON o.`CustomerID` = u.`id`
                    LEFT JOIN `cq_balikbayan_boxes` bb ON o.`BB_ID` = bb.`ID`
                    LEFT JOIN `cq_balikbayan_boxes` bbb ON i.`BB_ID` = bbb.`ID`
                    LEFT JOIN `cq_route_new` AS r ON i.`RouteID` = r.`ID`
                    LEFT JOIN `cq_route_new` AS rr ON o.`RouteID` = rr.`ID`
                    LEFT JOIN `addresses` a ON o.`Destination_Address` = a.`ID`
                    LEFT JOIN `cq_locality` loc ON a.`locality_id` = loc.`ID`
                    LEFT JOIN `cq_city` cy ON loc.`CityID` = cy.`ID`
                    LEFT JOIN `cq_city` ocy ON i.`CityID` = ocy.`ID`
                    LEFT JOIN `cq_provice` p ON cy.`provinceID` = p.`ID`
                    LEFT JOIN `cq_provice` op ON ocy.`provinceID` = op.`ID`
                    LEFT JOIN `users` wp_agent ON co.`Agent_ID` = wp_agent.`WP_ID`
                    LEFT JOIN `users` oss_agent ON o.`StaffID` = oss_agent.`id`
                    #WHERE i.`BoxNumber` IN (".$invoice_nums.")
                    ORDER BY AgentName ASC, InvoiceNumber ASC

Есть ли способ как-то облегчить это?