甲骨文显示购买汽车最多的客户

Question

我目前正在尝试回答以下问题：

显示从 Archie's Luxury Motors 购买汽车最多的客户的姓名。

我正在使用的表格：

客户

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

销售交易

(VIN, custID, agentID, dateOfSale, agreedPrice)

我试过以下查询：

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

请告诉我哪里做错了。

Answer 1

使用联接而不是在 where 子句中加入它们，同时将

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);

Answer 2

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

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

使用排名的最简单方法：

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;

甲骨文显示购买汽车最多的客户

Oracle display customer who purchased most cars

sql

oracle

group-by