The specified field reference could refer to more than one table listed in the FROM clause of your SQL statement. In the following example, the OrderID field exists in both the Orders and Order Details tables:
SELECT OrderID
FROM Orders, [Order Details];
Because the statement does not specify which table OrderID belongs to, it produces this error. To complete this operation, fully qualify the field reference by adding a table name. For example:
SELECT Orders.OrderID
FROM Orders, [Order Details];