ORACLE SQL语句调用表而不仅仅是具有产品视图的客户

Question

我有如下表格：

Customer(CustomerID, UserName, Email, CustomerType)
CustomerVisit(CustomerVisitID, CustomerID, VisitDateTime, VisitLength)
Product(ProductCode, ProductName, ProductDescription, QuantityInStock, UnitPrice)
ProductView(CustomerVisitID, ProductCode, AddedToBasket)

我的命令如下

select customerid, customervisitid,  count(customervisitid)
from customer_aqd, productview_aqd
group by customerid, customervisitid

我知道如何在不重复customervisitid的情况下代表使用customerid和customersid查看过的所有商品，因为我不希望任何人没有任何productview数据。

所以，为了清楚起见，我只希望能够看到表格中有productview的客户，看看他们customervisits <{}有多少customerid < em>但仅限于他们拥有productview数据。

Answer 1

Inner join CustomerVisit_aqd表到ProductView_aqd表：

select cv.customerid, cv.customervisitid,  count(cv.customervisitid)
from productview_aqd p
inner join customervisit_aqd cv on cv.CustomerVisitID = p.CustomerVisitID
group by cv.customerid, cv.customervisitid