I am trying to select and print customer_name(customer table), room_number(room table), room_rate (room table),rate_type(reservation table), checkin_date(reservation table), checkout_date(reservation table), billing_amount(billing table) from multiple tables. I tried to do an inner join but the error is 'column ambiguously defined '
SELECT *
FROM Customer c
INNER JOIN Reservation r
ON c.customer_id = r.customer_id
INNER JOIN Room s
ON s.room_id = r.room_id
INNER JOIN billing b
ON reservation_id = b.reservation_id
WHERE c.customer_name = 'John Scott';
You're missing the table alias on the left side of the last JOIN. Try this:
SELECT *
FROM Customer c
INNER JOIN Reservation r
ON c.customer_id = r.customer_id
INNER JOIN Room s
ON s.room_id = r.room_id
INNER JOIN billing b
ON r.reservation_id = b.reservation_id
WHERE c.customer_name = 'John Scott';
One problem is in your join and one in your select:
SELECT *
-------^ duplicate column names
FROM Customer c INNER JOIN
Reservation r
ON c.customer_id = r.customer_id INNER JOIN
Room s
ON s.room_id = r.room_id INNER JOIN
billing b
ON reservation_id = b.reservation_id
--------^ missing table alias
WHERE c.customer_name = 'John Scott';
If the only duplicate columns are the JOIN keys, then the USING clause (standard but not supported by all databases) is a handy way to get all the columns:
SELECT *
FROM Customer c INNER JOIN
Reservation r
USING (customer_id) INNER JOIN
Room s
USING (room_id) INNER JOIN
billing b
USING (reservation_id)
WHERE c.customer_name = 'John Scott';
When you using USING, the key columns are not duplicated with SELECT *.
Related
I am trying to create normalization 3 nf (normal form) in this database. However, when I execute the query, the table is empty. As you will see, this is my table and diagram.
Here is the relationship that we want to 3NF
Torder->(Customer-Food-Carrier-Waiter)-(Ternary Relationship)-(Customer_id,Food_id,Carrier_id,Waiter_id)
Here is my query
SELECT
Customers.ID AS CustomerID,
Food.ID AS FoodID,
Carrier.ID AS CarrierID,
Waiter.ID AS WaiterID,
tOrder.ID AS TORDERID
FROM
tOrder
INNER JOIN
Customers ON Customers.ID = tOrder.Customer_id
INNER JOIN
Food ON Food.ID = tOrder.Food_id
INNER JOIN
Carrier ON Carrier.ID = tOrder.Carrier_id
INNER JOIN
Waiter ON Waiter.ID = tOrder.Waiter_id
ORDER BY tOrder.ID;
Clearly, you have an issue where some of the tables are empty or the ids do not match. You can use LEFT JOIN to keep all orders and see what is happening:
FROM tOrder o LEFT JOIN
Customers c
ON c.ID = o.Customer_id LEFT JOIN
Food f
ON f.ID = o.Food_id LEFT JOIN
Carrier ca
ON ca.ID = o.Carrier_id LEFT JOIN
Waiter w
ON w.ID = o.Waiter_id
If there are no matches, then the orders are still in the results, with NULL for the values in the table with no matches.
Note that this also introduces table aliases, so the query is easier to write and to read.
Based on the following ERD, I'm trying to write a query that displays reservations made directly by customers and include reservation id, reservation date, customer id, customer first name, tour trip id, tour category name, tour trip date
I've been able to include everything in my query except for the tour category name because the TOUR_SITES table is in the way. Is there a way I can join the category name from the TOUR_PACKAGE table without adding any extra columns?
SELECT r.RESERVATION_ID, r.RESERVATION_DATE,
c.CUSTOMER_ID, c.FIRST_NAME,t.TRIP_ID, o.TRIP_DATE/*, P.CATEGORY_NAME*/
FROM CUSTOMER c
INNER JOIN RESERVATION r
ON
r.CUSTOMER_ID=c.CUSTOMER_ID
INNER JOIN TOURTRIP_RESERVATION t
ON
r.RESERVATION_ID=t.RESERVATION_ID
INNER JOIN TOUR_TRIP O
ON
t.TRIP_ID=o.TRIP_ID
WHERE AGENT_ID IS NULL;
Is there a way I can join the category name from the TOUR_PACKAGE table without adding any extra columns?
Sure; just join all tables you need. You don't have to add additional columns (the ones you don't need) into the select column list, but you do have to use the tour_sites table anyway.
Something like this:
select r.reservation_id, r.reservation_date,
c.customer_id, c.first_name,t.trip_id, o.trip_date,
p.category_name
from customer c inner join reservation r on r.customer_id=c.customer_id
inner join tourtrip_reservation t on r.reservation_id=t.reservation_id
inner join tour_trip o on t.trip_id=o.trip_id
--
join tour_sites s on s.tour_siteid = o.tour_siteid --> add
join tour_package p on p.category_id = s.category_id --> this
where agent_id is null;
You need to first join tour_sites with tour_trip on TOUR_SITEID and then join tour_package with tour_sites on category_id to get the tour category_name. You can join left join on tour_sites in case there are no tour sites assigned for a tour trip like a newly added tour_trip.
SELECT r.RESERVATION_ID, r.RESERVATION_DATE, c.CUSTOMER_ID, c.FIRST_NAME,t.TRIP_ID, o.TRIP_DATE,TP.CATEGORY_NAME
FROM CUSTOMER c
INNER JOIN RESERVATION r ON r.CUSTOMER_ID=c.CUSTOMER_ID
INNER JOIN TOURTRIP_RESERVATION t ON r.RESERVATION_ID=t.RESERVATION_ID
INNER JOIN TOUR_TRIP O ON t.TRIP_ID=o.TRIP_ID
LEFT JOIN TOUR_SITES TS ON TS.TOUR_SITEID = O.TOUR_SITEID
INNER JOIN TOUR_PACKAGE TP ON TP.CATEGORY_ID = TS.CATEGORY_ID
WHERE AGENT_ID IS NULL;
We are trying to find the names of the customers who have both a loan and an account in the same branch. Should we use inner join here? So far we have only written;
select DISTINCT customer.name
FROM Customer, Has_Loan, Branch, Has_Account
WHERE
We have tried a few different things without getting any further, so appreciate any kind of help or hint:)
You can try this :
SELECT DISTINCT Customer.Name
FROM Customer
INNER JOIN Has_Account ON Customer.Ssn = Has_Account.Assn
INNER JOIN Account ON Account.AccountNo = Has_Account.ANo
INNER JOIN Has_Loan ON Customer.Ssn = Has_Loan.Lssn
INNER JOIN Loan ON Loan.LoanNo = Has_Loan.LNo
WHERE Loan.BranchID = Account.BranchID
select c.name
from customer c
join has_loan hl on hl.lssn = c.ssn
join loan l on hl.lno = l.loanno
join has_account ha on ha.assn = c.ssn
join account a on ha.ano = a.accountno
join branch b on b.branchid = a.branchid
where l.branchid = a.branchid
group by c.name;
SELECT agents.aname,products.pname,customers.cname
FROM products INNER JOIN
(customers INNER JOIN agents
(INNER JOIN orders ON orders.pid=products.pid)
ON orders.cid=customers.cid)
ON orders.aid=agents.aid;
I am getting an error in line 4 for a missing keyword. Any ideas?
You need to add the ON condition after each table JOIN
SELECT agents.aname,
products.pname,
customers.cname
FROM products
INNER JOIN orders
ON orders.pid = products.pid
INNER JOIN customers
ON orders.cid = customers.cid
INNER JOIN agents
ON orders.aid = agents.aid;
I was tasked to create a new report on a legacy program. I needed to LEFT JOIN a table but I am getting Syntax error on JOIN Operation.
My SQL query as follows:
SELECT
SUM(b.qty) as qty,
b.price,
c.item_desc,
a.cust_name,
e.curr_symbol
FROM (
tran_hdr a,
tran_dtl b,
items c ,
tailoring e
(
LEFT JOIN
customers d
ON a.cust_name = d.name
)
)
WHERE a.tran_id = b.tran_id
AND b.item_no = c.item_no
GROUP BY b.price,
c.item_desc,
a.cust_name,
e.curr_symbol
I am joining the tran_hdr to customers. Because not all customers in Tran Header is maintained in customer table, but report requirest to show all Data in Transaction table.
You're messing up your JOINs.
And your Tailoring table has no relation whatsoever to other table.
So, just try this one out:
SELECT
b.price,
c.item_desc,
a.cust_name,
e.curr_symbol,
SUM(b.qty) as qty
FROM
tran_hdr a
INNER JOIN tran_dtl b
ON a.tran_id = b.tran_id
INNER JOIN items c
ON b.item_no = c.item_no
LEFT JOIN
customers d
ON a.cust_name = d.name
,tailoring e
GROUP BY b.price,
c.item_desc,
a.cust_name,
e.curr_symbol