Mysql 如何在SQL中显示3个不同表中的多列？

我有三张桌子：

预订、旅行、顾客

我只需要显示有多个预订的客户的行程名称、行程类型、客户名字、客户姓氏

有点像这样

预订表

预订号。。客户数量

16001 101 16002 101 16003 102 16004 103 16005 103 客户表

客户识别号。。客户数量

30 101 31 102 32 103 Customer表的主ID是Customer_ID，列名称为 Customer_Num。此列名也在预订表中

预订表的主id是预订\u id

我试过：

SELECT Customer.First_Name, Customer.Last_Name, Trip.Trip_Name, Trip.Type, Reservation.Customer_Num COUNT(Reservation.Customer_Num
FROM Reservation, Customer, Trip
WHERE Reservation.Customer_Num = Customer.Customer_Num
HAVING COUNT(Reservation.Customer_Num) > 1
GROUP BY Customer.First_Name, Customer.Last_Name, Trip.Trip_Name, Trip.Type, Reservation.Customer_Num;

---

假设您的行程表中有行程名称、行程类型等列，您可以尝试下面的查询-

SELECT Customer.First_Name
      ,Customer.Last_Name
      ,Trip.Trip_Name
      ,Trip.Type
      ,Reservation.Customer_Num
      ,COUNT(Reservation.Customer_Num) Customer_Num_Cnt
FROM Reservation R
INNER JOIN Customer C ON Reservation.Customer_Num = Customer.Customer_Num
INNER JOIN Trip T ON R.TRIP_ID = T.TRIP_ID
GROUP BY Customer.First_Name
        ,Customer.Last_Name
        ,Trip.Trip_Name
        ,Trip.Type
        ,Reservation.Customer_Num
-- HAVING COUNT(Reservation.Customer_Num) > 1;

---

如果这不符合您的要求，请共享TRIP表和CUSTOMER表的完整结构。

尝试此操作，假定TRIP表使用CUSTOMER_num字段作为外键

select A.Customer_id, A.Name, A.Last_name, B.name, B.type from Customer as A
where Customer_id in 
    (select Customer_Num from Reservation group by Customer_Num having count(Customer_Num) > 1)
left join Trip as B on Trip.Customer_Num = Customer.Customer_Num

您可以使用EXISTS：

---

您需要调整行程表的ON子句，因为您没有指定表信息。

这将显示结果，以便我可以选择具有多个预订的名称。在预订表中，它列出了拥有多个预订的客户编号，但我不确定为什么它不起作用

---

选择CUSTOMER.FIRST\u NAME、CUSTOMER.LAST\u NAME、TRIP.TRIP\u NAME、TRIP.TYPE、RESERVATION.CUSTOMER\u NUM、COUNTRESERVATION.CUSTOMER\u NUM CUSTOMER\u NUM

预订

CUSTOMER.CUSTOMER\u NUM=RESERVATION.CUSTOMER\u NUM上的内部加入客户 预订时的内部连接行程。行程\u ID=行程。行程\u ID

按CUSTOMER.FIRST\u NAME、CUSTOMER.LAST\u NAME、TRIP.TRIP\u NAME、TRIP.TYPE、RESERVATION.CUSTOMER\u NUM分组 注释掉COUNTRESERVATION.CUSTOMER_NUM>1

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请分享样本数据和预期结果。Hi@MTcodes和行程表在哪里？另外，是否向我们展示您迄今为止尝试过的代码？我添加了trip表以及其他两个表，只是为了澄清。使用了代码，但必须删除每个表名后的“C”“R”和“T”，而只使用完整的表名。它表示找不到数据选择CUSTOMER.FIRST\u NAME，CUSTOMER.LAST\u NAME，TRIP.TRIP\u NAME，TRIP.TYPE，RESERVATION.CUSTOMER\u NUM，COUNTRESERVATION.CUSTOMER\u NUM CUSTOMER\u NUM CUSTOMER\u NUM CNT从预订内部加入预订中的客户。CUSTOMER\u NUM=CUSTOMER.CUSTOMER\u NUM内部加入预订中的行程。TRIP\u ID=TRIP.TRIP\u ID按客户分组。FIRST\u NAME，CUSTOMER.LAST\u NAME、TRIP.TRIP\u NAME、TRIP.TYPE、RESERVATION.CUSTOMER\u NUM具有COUNTRESERVATION.CUSTOMER\u NUM>1；可能是HAVING condition正在筛选所有记录，因为在预订表中可能没有超过2个条目的客户。只需删除HAVING子句，然后重试。为了您的方便，我更新了查询以注释Having子句。谢谢您的帮助！！

SELECT t.*, c.*
FROM reservation r INNER JOIN
     customer c
     ON c.Customer_Num = r.Customer_Num INNER JOIN
     trip t
     ON . . .
WHERE EXISTS (SELECT 1 
              FROM reservation r1 
              WHERE r1.customer_no = r.customer_no AND 
                    r1.Reservation_ID <> r.Reservation_ID 
             );