H . using a common table expression to selectively step through a recursive relationship in a select statement H .使用公用表表達式來有選擇地執行select語句中的遞歸操作
There is an intrinsic recursive relationship in the bill of material structure that indicates the relationship between a parent product and the components that make up that product 物料清單結構本身是一種嵌套結構,指示父級產品和構成該產品的組件之間的關系。