SQL查詢來獲取客戶提供超過一票

Question

這裏是架構：

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

問題查詢是：顯示所有誰已預訂超過一票的顧客。我正在使用Oracle 9.兩個表的custid之間都有一個外鍵。

Answer 1

This？

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

如果你想從tblCustomers使用這個有各個領域：

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

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)