Question

我目前正在尝试回答以下问题：

显示从Archie的Luxury Motors购买最多汽车的客户的名字。

表I＆＃39;我正在使用：

客户

(custID, name, DOB, streetAddress, suburb, postcode,
gender, phoneNo, email, type)

SalesTransaction

(VIN, custID, agentID, dateOfSale, agreedPrice)

我尝试了以下查询：

select customer.name
from customer, salestransaction
where customer.custid = salestransaction.custid
group by (salestransaction.custid)
having count(salestransaction.custid) = max(salestransaction.custid);

我收到以下错误：

ORA-00979: not a GROUP BY expression

请告诉我我做错了什么。

Answer 1

最简单的方法是使用RANK：

select customer.name, st.cnt
from customer
join
 ( 
   select 
      custid,
      count(*) as cnt,
      rank() over (order by count(*) desc) as rnk
   from salestransaction
   group by custid
 ) st
on customer.custid = st.custid 
where st.rnk = 1;

Answer 2

http://www.exmaple.com/images/img1.png

Answer 3

可能这应该有效：

select * from (
select customer.name
from customer, salestransaction
where customer.custID = salestransaction.custID
group by (salestransaction.custID), customer.name
order by count(*) desc
) where rownum=1

Answer 4

使用连接而不是在where子句中加入它们，同时放入

SELECT c.name, MAX(s.custid) FROM (
SELECT c.name, Count(s.custid)
FROM customer c
INNER JOIN salestransaction s ON c.custid = s.custid
GROUP BY c.name);

Oracle显示购买了大多数汽车的客户

4 个答案: