如何用求和函数连接三个表

Question

我有三个以客户名称为主键的表。

我想通过 Customer Name 和 Sum the Quantities 组合所有三个表。

请帮我把第三张表也拼起来

我设法合并了一个表，但无法添加第二个表。我的查询是这样的

SELECT Stock.Customer, SUM(Stock.[Available Quantity]) AS AvailableQty, O.ShippedQty
FROM     (SELECT Storer, SUM([Shipped Quantity]) AS ShippedQty
                  FROM      Dispatch
                  GROUP BY Customer) AS O LEFT OUTER JOIN
                  Stock ON Stock.Customer= O.Customer
GROUP BY Stock.Customer, O.ShippedQty

Answer 1

   SELECT st.customer_name , rt.recieved_quantity, dt.dispatch_quantity
   FROM Stock_Table st
   LEFT JOIN   Receipt_Table rt
   ON st.customer_name = rt.customer_name
   LEFT JOIN Dispatch_Table dt
   ON st.customer_name = dt.customer_name