Question

noob to SQL。我必须创建一个查询，按月返回客户列表（按名称）及其收入和访问量。不幸的是，我不知道如何做到这一点，因为我班上的书并没有涵盖与此类似的任何内容。这是我到目前为止所提出的......我想我已经接近但我真的不知道下一步该做什么！

SELECT customer_first_name, customer_middle_initial, customer_last_name, 
price – cost as revenue, datepart(mm,date) as Month COUNT(receipt_number) 
as Visits 
FROM Customers, invoice4477 
WHERE Customers.customer_id = invoice4477.customer_id 
GROUP BY Visits 
ORDER BY customer_last_name desc

你能指点我正确的方向吗？用noob说话？我真的不知道自己在做什么。我使用的记录是这个问题在数据库中真正相关的唯一记录。我只是不明白如何按月订购访问次数和每次访问收入。

此外，我没有办法测试代码，因为我没有实际的数据库，只是表格的截图（这是真正的问题，否则我可能会对其进行故障排除直到我找到答案）。

Tables

我想我希望输出看起来像这样：

Customer Name    Revenue    Visits    Month
Joe Bob          $100       2         January
Joe Bob          $34        1         February
Sally Sue        $2443      5         January
Sally Sue        $243       4         June

请帮忙！谢谢:)）

Answer 1

适用于 Oracle PL / SQL

 SELECT Customer
        , Month
        , COUNT(ReceiptNo) AS Visits
        , SUM(Revenue) AS Revenue
   FROM (SELECT customer_first_name || ' ' || customer_middle_initial || '. ' ||  customer_last_name as Customer
                , to_char(date, 'Month') AS Month
                , invoice4477.cost - invoice4477.price as Revenue
                , receipt_number AS ReceiptNo
           FROM Customers 
                INNER JOIN invoice4477 ON Customers.customer_id = invoice4477.customer_id)
  GROUP BY Customer, Month;

架构：列名在我的示例

中有所不同

create table x(REC_NO int, CUST_ID int, RDATE date, price int, cost int);
create table cust (cust_id int, fname varchar2(20)
                   , mname varchar2(20), lname varchar2(20));

insert into x (rec_no, cust_id, rdate, price, cost) values
              (100, 1, to_date('08/04/2015','dd/mm/yyyy'), 150, 200);
insert into x (rec_no, cust_id, rdate, price, cost) values
              (101, 2, to_date('08/03/2015','dd/mm/yyyy'), 70, 80);
insert into x (rec_no, cust_id, rdate, price, cost) values
              (102, 1, to_date('07/01/2015','dd/mm/yyyy'), 50, 90);
insert into x (rec_no, cust_id, rdate, price, cost) values
              (103, 3, to_date('07/02/2015','dd/mm/yyyy'), 10, 200);
insert into x (rec_no, cust_id, rdate, price, cost) values
              (104, 3, to_date('07/01/2015','dd/mm/yyyy'), 10, 200);
insert into x (rec_no, cust_id, rdate, price, cost) values
              (104, 3, to_date('09/01/2015','dd/mm/yyyy'), 29, 200);              
insert into cust (cust_id, fname, mname, lname) values
              (1, 'john1','x', 'doe');
insert into cust (cust_id, fname, mname, lname) values
              (2, 'john2','x', 'doe');
insert into cust (cust_id, fname, mname, lname) values
              (3, 'john3','x', 'doe');

<强> SQL

SELECT CNAME
       , RMonth as Month
       , SUM(REVENUE) as Revenue
       , COUNT(REC_NO) as Visits
  FROM (SELECT fname || ' ' || mname || '. ' || lname as CName
               , to_char(RDATE, 'Month') AS RMonth
               , x.cost - x.price as Revenue
               , REC_NO
          FROM cust INNER JOIN x ON cust.cust_id = x.CUST_ID)
  GROUP BY CNAME, RMonth;

我得到的结果如下

|        CNAME |     MONTH | REVENUE | VISITS |
|--------------|-----------|---------|--------|
| john1 x. doe | April     |      50 |      1 |
| john2 x. doe | March     |      10 |      1 |
| john3 x. doe | February  |     190 |      1 |
| john3 x. doe | January   |     361 |      2 |
| john1 x. doe | January   |      40 |      1 |

现在，请注意，这可能不是这样做的可行方法，但这可行..： - ）

Answer 2

这是一个T-SQL解决方案。尝试一下，如果需要任何调整，请告诉我。

SELECT  C.customer_first_name,
        C.customer_last_name,
        CONCAT('$',SUM(I.price)) AS Revenue, --not sure whether you wanted price or cost
        COUNT(*) AS Visits,
        DATENAME(MONTH,I.[date]) AS [Month]
FROM Customers C
INNER JOIN invoice4477 I
ON C.CustomerID = I.CustomerID
GROUP BY C.CustomerID,C.customer_first_name,C.customer_last_name,DATENAME(MONTH,I.[Date])

如何创建一个查询，按月返回客户列表（按名称）及其收入和访问次数

2 个答案: