sql - SQL查询获取多于一张票的客户

Question

这是架构：

 tblCustomers{custid,fname,lname,email}
 tblTicket{ticketId,custid,numOfPassengers,dateofJourney,totafare,trainId}

问题查询是：显示所有预订多于一张票的客户。我正在使用 Oracle 9。两个表的 custid 之间有一个外键。

Answer 1

这？

SELECT C.custid
FROM tblCustomers C
  JOIN tblTickets T
    ON C.custid = T.custid
GROUP BY C.custid
HAVING COUNT(*) > 1

如果您想拥有 tblCustomers 的所有字段，请使用以下命令：

SELECT C.custid,C.fname,C.lname,C.email
FROM tblCustomers C
  JOIN tblTickets T
    ON C.custid = T.custid
GROUP BY C.custid,C.fname,C.lname,C.email
HAVING COUNT(*) > 1

或者

SELECT
       C.custid,
       MAX(C.fname) as fname,
       MAX(C.lname) as lname,
       MAX(C.email) as email
FROM tblCustomers C
  JOIN tblTickets T
    ON C.custid = T.custid
GROUP BY C.custid
HAVING COUNT(*) > 1

Answer 2

select  * 
from    tblCustomers 
where   custid in (select custid from tblTicket group by custid having count(*) > 1)