If the &quot; price &quot; (for the individual price of an article) and &quot; Supplier_No &quot; (for the supplier of the article) fields exist in the &quot; Item &quot; table, you can obtain the average price of the item that a supplier provides with the following query:
如果在表格 &quot; Item &quot; 中有字段 &quot; preice &quot; （货物的单价）和字段 &quot; Supplier_No &quot; （货物的供应商），那么您就能用以下查询得到供应商提供的货物的平均价格：