需要计算顾客光顾店铺的次数

Question

我需要计算客户光顾商店的次数。连同购买的物品。在这种情况下，客户访问商店 3 次并购买了 5 件商品。现在当我计算访问次数时，我的输出是 5。

下面是我尝试的查询：

select 
    Receipt_no,
    Customer,sales_item,
    Amount,
    sum(Amount) over (partition by customer) as total_sales,
    count(Receipt_No) over (partition by customer) as No_of_Visit 
from sales
left join customer where sales.Customer = customer.Customer

我的输出是

Receipt_No  Customer  sales_item  Amount  total_sales  No_of_Visit
5           C1        Item1       100     1200         5
5           C1        Item3       200     1200         5
5           C1        item4       200     1200         5
34          C1        item1       300     1200         5
35          C1        item2       400     1200         5

但我希望 No_of_Visit 为“3”

Answer 1

我认为您需要明确的收据计数。那可能是：

count(distinct receipt_no) over (partition by customer) as No_of_Visit

但不幸的是，SQL Server 不支持窗口函数中的distinct。但是，您可以使用 dense_rank() 模拟它：

dense_rank() over (partition by customer order by receipt_no) 
    + dense_rank() over (partition by customer order by receipt_no desc) 
    - 1 as No_of_Visit