Query contains ambiguous (outer) joins.
Error 3285
You tried to execute an SQL statement For example, this error can occur if you execute the following SQL statement:
SELECT * FROM Customers, Orders, [Order Details],
Customers LEFT JOIN Orders
ON Customers.[Customer ID] = Orders.[Customer ID],
Orders INNER JOIN [Order Details]
ON Orders.[Order ID] = [Order Details].[Order ID];
Execution of this statement produces an error because the order of the joins is ambiguous. To force one of the joins to be performed first, create a separate query that performs the first join and then include that query in your SQL statement. The following queries illustrate how you might construct the preceding query so that the INNER JOIN Operation (SQL) operation is performed before the LEFT JOIN, RIGHT JOIN Operations (SQL) operation:
Query1
SELECT * FROM Orders, [Order Details],
Orders INNER JOIN [Order Details]
ON Orders.[Order ID] = [Order Details].[Order ID];
Query2
SELECT * FROM Customers, Query1,
Customers LEFT JOIN Query1
ON Customers.[Customer ID] = Orders.[Customer ID];