我在期末考试前试了几个问题

Question

这是图图表

我似乎想不出怎么回答这些问题。我不擅长加入，有人能帮我帮我商店的供应商提供一个查询，以显示商店和供应商向那些商店供应产品的情况。显示商店名称和商店经理，供应商名称，联系名称和供应商的电话号码。

Answer 1

让我们试试：

查询8-对不起，没有真正理解它。

查询9-

SELECT ShiftID, EndTime - StartTime AS Downtime, T2.* FROM SHIFT T1 JOIN STAFF T2 ON T1.StaffID = T2.StaffID WHERE EndTime - StartTime >= 28 ORDER BY EndTime - StartTime DESC;

查询10 -

SELECT T1.*, Type, FibreContent, CarboContent, NULL AS FatContent, NULL AS ProteinContent FROM PRODUCT T1 JOIN VEGETARIAN T2 ON T1.ProductID = T2.ProductID UNION SELECT T1.*, Type, NULL FibreContent, NULL CarboContent, FatContent, ProteinContent FROM PRODUCT T1 JOIN HEALTHY T2 ON T1.ProductID = T2.ProductID ORDER BY Type;