如何聯接三個表並從三個表中以及在oracle中檢索選定的列？

Question

我有3張桌子。 電影院，訂票和顧客

create table cinema
(
c_id int,
location varchar(10)
)
insert into cinema values(1,'New York');
insert into cinema values(2,'London');
insert into cinema values(3,'Paris');

create table booking
(
c_id int,
cust_id int
)

insert into booking values(1,10);
insert into booking values(2,11);
insert into booking values(3,12);
insert into booking values(3,13);
insert into booking values(2,14);

create table customer
(
cust_id int,
cust_name varchar(10)
)

insert into customer values(10,'sam');
insert into customer values(11,'adrian');
insert into customer values(12,'mark');
insert into customer values(13,'jim');
insert into customer values(14,'tom');

我想選擇尚未在巴黎預訂的所有客戶的客戶ID（即cust_id），客戶名稱（cust_name）和位置（來自電影院表）。

我想要的是-

cust_id cust_name location
10      sam       New York   
11      adrian    London
14      tom       London

我嘗試了很多。。。我的代碼之一是-

SELECT customer.cust_id,customer.cust_name,
cinema.location as Location FROM booking,cinema,customer
WHERE booking.c_id=cinema.c_id AND location!='Paris';

它給了我15個結果..我想不出該怎么做..請幫助我。

Answer 1

在您的代碼中，您沒有加入booking給customer ，這導致了您的問題。 我在這里使用顯式聯接而不是隱式聯接。 盡管沒有區別 ，但顯式語法是標准的。

select cu.cust_id, cu.cust_name, ci.location
  from cinema ci
  join booking b
    on ci.c_id = b.c_id
  join customer cu
    on b.cust_id = cu.cust_id
 where ci.location <> 'Paris'

我不確定您的預訂表的結構。 我希望有更多列，例如票數等。

Answer 2

您的WHERE statement不是您想要的那么具體。 您需要一個與booking.cust_id to customer.cust_id相匹配的條件：

WHERE booking.c_id = cinema.c_id 
AND booking.cust_id = customer.cust_id
AND location != 'Paris'

現在，您正在為所有客戶組合獲取結果。

Answer 3

請參閱以下示例：

Select   
businessuser.UserName,
businessuser.EmailAddress,
businessimages.ImgName, 
featured_cart.FeaturedPlan,featured_cart.StartDate
From featured_cart
Inner Join businessimages on featured_cart.FeaturedProId = businessimages.IdBusinessImages 
Inner Join businessuser  on businessimages.UserId = businessuser.IdBusinessUser
and featured_cart.FeaturedType = "Featured Email"

3張桌子是：

1. businessuser
2. businessimages
3. featured_cart

這個例子工作正常...

Answer 4

MS SQL Server 2008：

select cust_id, cust_name, location
from customer c 
inner join booking b 
inner join location l
on c.cust_id = b.cust_id and b.c_id=l.c_id

Answer 5

復合聯接聯接四個表：

二手4桌

1. 顧客
2. 命令
3. 訂單詳細信息
4. 制品

本示例可以100％起作用您可以在W3schools中嘗試使用此方法-內部聯接“嘗試一下” SQL編輯器表來自W3schools編輯器。

查詢：

Select Customers.CustomerName as Table1_Customer, Orders.EmployeeID as Table2_Employee, OrderDetails.Quantity as Table3_OrderDetails,Products.ProductName as Table4_Products 
From Customers
INNER JOIN Orders 
ON Customers.CustomerID = Orders.CustomerID
INNER JOIN OrderDetails 
ON Orders.OrderID = OrderDetails.OrderID 
INNER JOIN Products
ON OrderDetails.ProductID = Products.ProductID Order by EmployeeID;

Answer 6

你好，你可以這樣使用join：

SQL

select customer.cust_id,customer.cust_name,cinema.location from cinema,customer,booking where cinema.c_id=booking.c_id and booking.cust_id=customer.cust_id and cinema.location not like 'paris';