I have the following code:
select O.ONO
from Customers C, Odetails Od, Orders O, Parts P
where P.PNO=Od.PNO and Od.ONO=O.ONO and O.CNO=C.CNO
group by O.ONO
order by sum(Od.QTY*P.PRICE)desc;
However, instead of selecting the O.ONO column, I need to select the C.CNAME from a different table. How would I go about doing that?
If what you want is a list of Customer Names ordered by the sum of their orders then just change your query from
select O.ONO
...
group by O.ONO
to
select C.CName
...
group by C.CName
This will display the customer name and the order number. NOTE: This will repeat the customer name as many times as there are orders for that customer
Also, my preferred style of SQL queries is
select C.CName
from Customers C
INNER JOIN Orders O ON C.CNO = O.CNO
INNER JOIN Odetails OD ON O.ONO = OD.ONO
INNER JOIN Parts P ON OID.PNO = P.PNO
where P.PNO=Od.PNO and Od.ONO=O.ONO and O.CNO=C.CNO
group by C.CName
order by sum(Od.QTY*P.PRICE)desc;
An additional suggestion to clarify your code. (please note: I'm not an oracle person), in my company (SqlServer) generally you would have the table named after the entity, with the primary key being just Id, and then any property named without a prefix. For instance does OID refer to OrderId or OfficeId?
EG:
Customer:
Id
Name
Order:
Id
CustomerId
Then your queries are much more readable:
SELECT Name
FROM Customer
INNER JOIN Order ON Customer.Id = Order.CustomerId
WHERE ...
ORDER BY Customer.Name
Please do like this,
select C.CNAME from Customers C, Odetails Od, Orders O, Parts P where P.PNO=Od.PNO and Od.ONO=O.ONO and O.CNO=C.CNO group by C.CNAME order by sum(Od.QTY*P.PRICE) desc;
The select statement will select the column specified
SELECT C.CNAME
FROM Customers C, Odetails Od, Orders O, Parts P
WHERE P.PNO=Od.PNO and Od.ONO=O.ONO and O.CNO=C.CNO
GROUP BY C.CNAME
ORDER BY sum(Od.QTY*P.PRICE)desc;
If you wish to still keep O.ONO column selected as well
SELECT C.CNAME, O.ONO
FROM Customers C, Odetails Od, Orders O, Parts P
WHERE P.PNO=Od.PNO and Od.ONO=O.ONO and O.CNO=C.CNO
GROUP BY C.CNAME
ORDER BY sum(Od.QTY*P.PRICE)desc;
Related
I have the following tables
Customer (CID, name, address)
Orders (CID, BID, onDate, quantity)
Device (DID, title, IMEI, price, MID)
Manufacturer (MID, name, address)
What SQL statement would allow me to retrieve the ID's and names of all
the customers who have spent atleast X amount (lets say 350 for example)
on devices made my the manufacturer "Sony". The list should include the total amount of money spent by each customer on those devices.
I assume that the table Orders contains a column DID (BID is a typo, right?) that relates it to the table device.
Join the tables, group by customer to aggregate and set the condition in the HAVING clause:
select c.CID, c.name,
sum(o.quantity * d.price) total_amount
from customer c
inner join orders o on o.CID = c.CID
inner join device d on d.DID = o.DID
inner join manufacturer m on m.MID = d.MID
where m.name = 'Sony'
group by c.CID, c.name
having sum(o.quantity * d.price) >= 350
I've a customer table and purchases table,
need to show cname, cid with max(customer_visits) from customer table
and sum of total_purchases by customer in purchases table.
I'm doing something like this
select p.cid, c.cname, sum(p.total_price)
from customers c where exists
(select max(visits_made) from customers having visits_made=max(visits_made)
and cid=p.cid)
inner join purchases p on p.cid=c.cid
group by p.cid,c.cname
and
select p.cid, c.cname, sum(p.total_price)
(select max(visits_made) from customers c where c.cid=p.cid)
from purchases p
inner join customers c on c.cid=p.cid
group by p.cid,c.cname
What's going wrong with these queries?
Found the solution, had to include where clause after inner join :D
I think this is just an aggregation query:
select p.cid, c.cname, sum(p.total_price) as total_price,
max(visits_made) as visits_made
from purchases p inner join
customers c
on c.cid = p.cid
group by p.cid, c.cname;
I am using three tables in a PostgreSql database as:
Customer(Id, Name, City),
Product(Id, Name, Price),
Orders(Customer_Id, Product_Id, Date)
and I want to execute a query to get from them "the customers that have have ordered at least two different products alnong with the products". The query I write is:
select c.*, p.*
from customer c
join orders o on o.customer_id = c.id
join product p on p.id = o.product_id
group by (c.id)
having count(distinct o.product_id)>=2
It throws the error:
"column "p.id" must appear in the GROUP BY clause or be used in an aggregate function
LINE 1: select c.*, p.*".
However if I remove the the p.* from select statement (assuming that I one does not want the products, only the customers), it runs fine. How can I get the products as well?
Update: Having ordered two or more products, a customer must appear on the output as many times as its product he has ordered. I want as output a table with 5 columns:
Cust ID | Cust Name | Cust City | Prod ID | Prod Name | Prod Price
Is it possible in SQL given that group by should be used? Shoul it be used on more than one columns on different tables?
Try this out :
SELECT distinct c.* ,p.*
FROM Customer c
JOIN
(SELECT o.customer_id cid
FROM Product P
JOIN Orders o
ON p.id= o.product_id
GROUP BY o.customer_id
HAVING COUNT(distinct o.product_id)>=2) cp
ON c.id =cp.cid
JOIN Orders o
on c.id=o.customer_id
JOIN Product p
ON o.product_id =p.id
I hope it solves your problem.
I think you can use following query for this question -
SELECT C1.*, p1.*
FROM Customer C1
JOIN Orders O1 ON O1.Customer_Id = C1.Id
JOIN Product P1 ON P1.Id = O1.Product_Id
WHERE C1.Id IN (SELECT c.Id
FROM Customer c
JOIN Orders o ON o.Customer_Id = c.Id
GROUP BY (c.Id)
HAVING COUNT(DISTINCT o.Product_Id) >= 2)
Having the following three tables in a DBMS:
Customer(Id, Name, City),
Product(Id, Name, Price),
Orders(Cust_Id, Prod_Id, Date)
What is the query which fetches the Customers (if any) who have ordered all Products?
select c.id
from customer c
inner join orders o on o.cust_id = c.id
inner join product p on p.id = o.prod_id
group by c.id
having count(distinct p.id) = (select count(id) from product)
I'm trying to do something like:
SELECT c.id, c.name, COUNT(orders.id)
FROM customers c
JOIN orders o ON o.customerId = c.id
However, SQL will not allow the COUNT function. The error given at execution is that c.Id is not valid in the select list because it isn't in the group by clause or isn't aggregated.
I think I know the problem, COUNT just counts all the rows in the orders table. How can I make a count for each customer?
EDIT
Full query, but it's in dutch... This is what I tried:
select k.ID,
Naam,
Voornaam,
Adres,
Postcode,
Gemeente,
Land,
Emailadres,
Telefoonnummer,
count(*) over (partition by k.id) as 'Aantal bestellingen',
Kredietbedrag,
Gebruikersnaam,
k.LeverAdres,
k.LeverPostnummer,
k.LeverGemeente,
k.LeverLand
from klanten k
join bestellingen on bestellingen.klantId = k.id
No errors but no results either..
When using an aggregate function like that, you need to group by any columns that aren't aggregates:
SELECT c.id, c.name, COUNT(orders.id)
FROM customers c
JOIN orders o ON o.customerId = c.id
GROUP BY c.id, c.name
If you really want to be able to select all of the columns in Customers without specifying the names (please read this blog post in full for reasons to avoid this, and easy workarounds), then you can do this lazy shorthand instead:
;WITH o AS
(
SELECT CustomerID, CustomerCount = COUNT(*)
FROM dbo.Orders GROUP BY CustomerID
)
SELECT c.*, o.OrderCount
FROM dbo.Customers AS c
INNER JOIN dbo.Orders AS o
ON c.id = o.CustomerID;
EDIT for your real query
SELECT
k.ID,
k.Naam,
k.Voornaam,
k.Adres,
k.Postcode,
k.Gemeente,
k.Land,
k.Emailadres,
k.Telefoonnummer,
[Aantal bestellingen] = o.klantCount,
k.Kredietbedrag,
k.Gebruikersnaam,
k.LeverAdres,
k.LeverPostnummer,
k.LeverGemeente,
k.LeverLand
FROM klanten AS k
INNER JOIN
(
SELECT klantId, klanCount = COUNT(*)
FROM dbo.bestellingen
GROUP BY klantId
) AS o
ON k.id = o.klantId;
I think this solution is much cleaner than grouping by all of the columns. Grouping on the orders table first and then joining once to each customer row is likely to be much more efficient than joining first and then grouping.
The following will count the orders per customer without the need to group the overall query by customer.id. But this also means that for customers with more than one order, that count will repeated for each order.
SELECT c.id, c.name, COUNT(orders.id) over (partition by c.id)
FROM customers c
JOIN orders ON o.customerId = c.id