Hi IM trying to build a query for the following sentence for sql.
For each seller and each item sold by the seller, find the total amount sold.
I have 3 tables but not sure If i have to use them all. I have a feeling I need to use at least three tables to get this query but I keep getting an error. Also, I keep getting an error when I try to the following:
select selleruserid, itemid, sum(price) total
from sales_fact s
join items_dim i on i.itemid = s.itemid
join sellers_dim d on d.userid = s.selleruserid
group by selleruserid, itemid
I added a picture below of my tables.
All the information you want is in the fact table, so the other tables do not seem necessary:
select sf.selleruserid, sf.itemid, sum(sf.price) as total
from sales_fact s
group by sf.selleruserid, sf.itemid;
You would need to join in the other tables if you needed other information from the dimension, such as the name.
Related
this is an answer to the question : We need a list of customer IDs with the total amount they have ordered. Write a SQL statement to return customer ID (cust_id in the Orders table) and total_ordered using a subquery to return the total of orders for each customer. Sort the results by amount spent from greatest to the least. Hint: you’ve used the SUM() to calculate order totals previously.
SELECT prod_name,
(SELECT Sum(quantity)
FROM OrderItems
WHERE Products.prod_id=OrderItems.prod_id) AS quant_sold
FROM Products
;
So there is this simple code up here, and I know that this WHERE clause is comparing two columns in two different tables. But since We are calculating the SUM of that quantity, why do need that WHERE clause exactly. I really couldn't get it. Why the product_id exactly and not any other column ( p.s: the only shared column between those two tables is prod_id column ) I am still a beginner. Thank you!
First you would want to know the sum for each product - so need to adjust the subquery similar to this:
(SELECT prod_id, Sum(quantity) qty
FROM OrderItems
group by prod_id
) AS quant_sold
then once you know how much for each product, then you can link that
SELECT prod_name,
(SELECT prod_id, Sum(quantity) qty
FROM OrderItems
group by prod_id
) AS quant_sold
FROM Products p
WHERE p.prod_id = quant_sold.prod_id
Run it without the where clause and compare the results. You'll learn a lot that way. specifically focus on two different product Ids ensuring they both have order items and quantities.
You have two different tables involved. There are multiple products. You don't want the sum of all orders on each product; which is what you would get without the where clause. So the where clause correlates the two tables ensuring you only SUM the quantity of each order item for each product between the tables. Personally, I'd use a join, sum, and a group by as I find it easier to read and I'm not a fan of sub selects in the select of another query; but that's me.
SELECT prod_name,
(SELECT Sum(quantity)
FROM OrderItems
WHERE Products.prod_id=OrderItems.prod_id) AS quant_sold
FROM Products
Should be the same as:
SELECT prod_name, Sum(coalesce(P.quantity,0))
FROM Products P
LEFT JOIN orderItems OI
on P.prod_id=OI.prod_id
GROUP BY Prod_Name
'Notes
the above is untested.
a left join is needed because all products should be listed and if a product doesn't have an order, the quantity would be zero.
if we use an inner join, the product would be excluded.
We use coalesce because you'd have a "Null" quantity instead of zero for such lines without an order item.
as to which is "right" well it depends and varies on different cases. each has it's own merits and in different cases, one will perform better than another, and in a different case, vice-versa. See --> Join vs. sub-query
As an example:
Say you have Products A & B
"A" has Order Item Quantities of 1 & 2
"B" has order item Quantities of 10 & 20
If we don't have the where clause every result record would have qty 33
If we have the where product "A" would have 3
product "B" would have qty 30.
I have two tables,
I need to find all monitor purchases (but not with monitor ID, instead I should use 'Monitor'). I have made code, but it takes the quantity for all products, not only for 'Monitor'.
The code I made:
select name, Price,sum(quantity)
from Products, Orders
where name='Monitor'
How can I fix this problem?
You need to link the rows of both tables. Right now you are creating the cartesian product, containing every row from the first table combined with every row from the second table. With your screenshot, that's going to be 9 rows in total.
SELECT name, Price, SUM(quantity)
FROM Products, Orders
WHERE name='Monitor'
AND Products.ProductId = Orders.ProductId
Or use JOIN directly to separate the filter condition from the join condition:
SELECT name, Price, SUM(quantity)
FROM Products
INNER JOIN Orders
ON Products.ProductId = Orders.ProductId
WHERE Products.name='Monitor'
I'm using Oracle 11g Application Express, and executing these commands within the SQL Plus CLI. This is for a class, and I cannot get past this problem. I don't know how to add the total quantity of the items on the orders - I get confused as I don't know how to take the SUM of the QUANTITY per ORDER (customers have multiple orders).
For each customer having an order, list the customer number, the number of orders
that customer has, the total quantity of items on those orders, and the total price for
the items. Order the output by customer number. (Hint: You must use a GROUP BY
clause in this query).
Tables (we will use):
CUSTOMER: contains customer_num
ORDERS: contains order_num, customer_num
ITEMS: contains order_num, quantity, total_price
My logic: I need to be able to calculate the sum of the quantity per order number per customer. I have sat here for over an hour and cannot figure it out.
So far this is what I can formulate..
SELECT customer_num, count(customer_num)
FROM orders
GROUP BY customer_num;
I don't understand how to GROUP BY very well (yes, I have googled and researched it for a bit, and it just isn't clicking), and I have no clue how to take the SUM of the QUANTITY per ORDER per CUSTOMER.
Not looking for someone to do my work for me, just some guidance - thanks!
select o.customer_num,
count(distinct o.order_num) as num_orders,
sum(i.quantity) as total_qty,
sum(i.total_price) as total_price
from orders o
join items i
on o.order_num = i.order_num
group by o.customer_num
order by o.customer_num
First thing:
you have to join the two tables necessary to solve the problem (orders and items). The related field appears to be order_num
Second thing:
Your group by clause is fine, you want one row per customer. But because of the join to the items table, you will have to count DISTINCT orders (because there may be a one to many relationship between orders and items). Otherwise an order with 2 different associated items would be counted twice.
Next, sum the quantity and total price, you can do this now because you've joined to the needed table.
This is also solved by using WHERE:
SELECT orders.customer_num, /*customer number*/
COUNT(DISTINCT orders.order_num) AS "num_orders", /*number of orders/c*/
SUM(items.quantity) as "total_qty", /*total quantity/c*/
SUM(items.total_price) as "total_price" /*total price/items*/
/* For each customer having an order, list the customer number,
the number of orders that customer has, the total quantity of items
on those orders, and the total price for the items.
Order the output by customer number.
(Hint: You must use a GROUP BY clause in this query). */
FROM orders, items
WHERE orders.order_num = items.order_num
GROUP BY orders.customer_num
ORDER BY orders.customer_num
;
I am using the following query to obtain some sales figures. The problem is that it is returning the wrong data.
I am joining together three tables tbl_orders tbl_orderitems tbl_payment. The tbl_orders table holds summary information, the tbl_orderitems holds the items ordered and the tbl_payment table holds payment information regarding the order. Multiple payments can be placed against each order.
I am trying to get the sum of the items sum(mon_orditems_pprice), and also the amount of items sold count(uid_orderitems).
When I run the following query against a specific order number, which I know has 1 order item. It returns a count of 2 and the sum of two items.
Item ProdTotal ProdCount
Westvale Climbing Frame 1198 2
This order has two payment records held in the tbl_payment table, which is causing the double count. If I remove the payment table join it reports the correct figures, or if I select an order which has a single payment it works as well. Am I missing something, I am tired!!??
SELECT
txt_orditems_pname,
SUM(mon_orditems_pprice) AS prodTotal,
COUNT(uid_orderitems) AS prodCount
FROM dbo.tbl_orders
INNER JOIN dbo.tbl_orderitems ON (dbo.tbl_orders.uid_orders = dbo.tbl_orderitems.uid_orditems_orderid)
INNER JOIN dbo.tbl_payment ON (dbo.tbl_orders.uid_orders = dbo.tbl_payment.uid_pay_orderid)
WHERE
uid_orditems_orderid = 61571
GROUP BY
dbo.tbl_orderitems.txt_orditems_pname
ORDER BY
dbo.tbl_orderitems.txt_orditems_pname
Any suggestions?
Thank you.
Drill down Table columns
dbo.tbl_payment.bit_pay_paid (1/0) Has this payment been paid, yes no
dbo.tbl_orders.bit_order_archive (1/0) Is this order archived, yes no
dbo.tbl_orders.uid_order_webid (integer) Web Shop's ID
dbo.tbl_orders.bit_order_preorder (1/0) Is this a pre-order, yes no
YEAR(dbo.tbl_orders.dte_order_stamp) (2012) Sales year
dbo.tbl_orders.txt_order_status (varchar) Is the order dispatched, awaiting delivery
dbo.tbl_orderitems.uid_orditems_pcatid (integer) Product category ID
It's a normal behavior, if you remove grouping clause you'll see that there really are 2 rows after joining and they both have 599 as a mon_orditems_pprice hence the SUM is correct. When there is a multiple match in any joined table the entire output row becomes multiple and the data that is being summed (or counted or aggregated in any other way) also gets summed multiple times. Try this:
SELECT txt_orditems_pname,
SUM(mon_orditems_pprice) AS prodTotal,
COUNT(uid_orderitems) AS prodCount
FROM dbo.tbl_orders
INNER JOIN dbo.tbl_orderitems ON (dbo.tbl_orders.uid_orders = dbo.tbl_orderitems.uid_orditems_orderid)
INNER JOIN
(
SELECT x.uid_pay_orderid
FROM dbo.tbl_payment x
GROUP BY x.uid_pay_orderid
) AS payments ON (dbo.tbl_orders.uid_orders = payments.uid_pay_orderid)
WHERE
uid_orditems_orderid = 61571
GROUP BY
dbo.tbl_orderitems.txt_orditems_pname
ORDER BY
dbo.tbl_orderitems.txt_orditems_pname
I don't know what data from tbl_payment you are using, are any of the columns from the SELECT list actually from tbl_payment? Why is tbl_payment being joined?
So, I have three tables with the following rows: Customers (Customer_id and Name), Orders (Customer_id, Product_id, Quantity) and Products (Price).
How do I write a query which shows all customers who spent more than 1000$? Do I have to join the tables?
Because this is homework, I'm not going to give you the answer, just information on how to arrive at the answer.
You need to include the customers table, because that's what your looking for, customers. You'll need to join in aggregate with the orders table, so you can find out how many of each product they've ordered, and you'll need to join with the products table to find the prices of all those items in order to total them up to determine if they've spent more than $1000.
Go to it. Tell us how you get on.
SELECT * FROM customer c JOIN (
SELECT a.customer_id,SUM(a.quantity*b.price) spent FROM orders a
JOIN products b ON b.product_id=a.product_id GROUP BY a.customer_id
) d ON d.customer_id=c.customer_id WHERE d.spent>1000