I neet to select TOP 2 products with Max Price.
ProductID ProductName SupplierID CategoryID Unit Price
1 Chais 1 1 10 bags 18
2 Chang 1 1 24 bottles 19
3 Aniseed Syrup 1 2 12 bottles 10
I have used:
Select TOP 2 *
from Products
where Price = (Select Max(Price) from Products);
But the result is just 1 row.
This will give you the top 2 max prices but if the same price is in there twice you would get the same value twice, but from your code above that is what it would do so assuming that is what you are looking for.
Select TOP 2 * from Products order by Price DESC
You need order by clause :
select top (2) *
from Products p
order by price desc;
Related
On a Rails (5.2) app with PostgreSQL I have 2 tables: Item and ItemPrice where an item has many item_prices.
Table Item
id
name
1
poetry book
2
programming book
Table ItemPrice
id
item_id
price
1
1
4
2
2
20
3
1
8
4
1
6
5
2
22
I am trying to select all the items for which the last price (price of the last offer price attached to it) is smaller than the one before it
So in this example, my request should only return item 1 because 6 < 8, and not item 2 because 22 > 20
I tried various combinations of Active records and SQL subqueries that would allow me to compare the last price with the second to last price but failed so far.
ex Item.all.joins(:item_prices).where('EXISTS(SELECT price FROM item_prices ORDER BY ID DESC LIMIT 1 as last_price WHERE (SELECT price FROM item_prices ... can't work it out..
You can do it as follows using ROW_NUMBER and LAG:
LAG to get the previous row based on a condition
WITH ranked_items AS (
SELECT m.*,
ROW_NUMBER() OVER (PARTITION BY item_id ORDER BY id DESC) AS rn,
LAG(price,1) OVER (PARTITION BY item_id ORDER BY id ) previous_price
FROM ItemPrice AS m
)
SELECT it.*
FROM ranked_items itp
inner join Item it on it.id = itp.item_id
WHERE rn = 1 and price < previous_price
Demo here
I have a table like this:
id | invoice_id | product_id | quantity | total
1 5 10 2 100
2 5 10 1 50
3 5 11 1 200
4 5 11 1 200
I want to combine the rows having same product_id in an invoice by adding their quantities and total values to one of the rows and then delete the other rows in the table. So the output should be like this
id | invoice_id | product_id | quantity | total
1 5 10 3 150
3 5 11 2 400
How can I do this? I was thinking of using an sql function that returns a list of id's having the same invoice and product and then using aggregate functions on quantity and price. Are there any simpler ways to do this?
First, you need an UPDATE statement that updates for each invoice_id, product_id combination the row with the min id with the totals of quantity and total:
UPDATE tablename t
SET quantity = s.quantity,
total = s.total
FROM (
SELECT MIN(id) id, SUM(quantity) quantity, SUM(total) total
FROM tablename
GROUP BY invoice_id, product_id
) s
WHERE s.id = t.id;
Then a DELETE statement to delete all the other ids:
DELETE FROM tablename t1
WHERE t1.id > (
SELECT MIN(t2.id)
FROM tablename t2
WHERE t2.invoice_id = t1.invoice_id AND t2.product_id = t1.product_id
);
See the demo.
This looks like an aggregation query:
select min(id) as id, invoice_id, product_id,
sum(quantity) as quantity, sum(total) as total
from t
group by invoice_id, product_id;
I've spent that last couple of days searching for a way to make a SQL query that searches the database and returns records where the SUM of the same ID's equal or grater then the value provided.
For this I've been using the W3schools database to test it out in the products table.
More so what I've been trying to do:
SELECT * FROM products
WHERE supplierid=? and SUM(price) > 50
in the "where supplier id" would loop through same suppliers and sum of their price higher than 50 in this case return the records.
In this case it would read supplier ID 1 then add the price of all that supplier 18+19+10=47 now 47 < 50 so it will not print those records at the end. Next supplier ID 2 22+21.35=43.35 and again would not print those records until the sum of price is higher than 50 it will print
I'm working with a DB2 database.
SAMPLE data:
ProductID ProductName SupplierID CategoryID Price
1 Chais 1 1 18
2 Chang 1 1 19
3 Aniseed 1 2 10
4 Chef Anton 2 2 22
5 Chef Anton 2 2 21.35
6 Grandma's 3 2 25
7 Uncle Bob 3 7 30
8 Northwoods 3 2 40
9 Mishi 4 6 97
10 Ikura 4 8 31
11 Queso 5 4 21
12 Queso 5 4 38
13 Konbu 6 8 6
14 Tofu 6 7 23.25
How about:
select * from products where supplierid in (
select supplierid
from products
group by supplierid
having sum(price) > 50
);
The subquery finds out all the supplierid values that match your condition. The main (external) query retrieves all rows that match the list of supplierids.
not tested, but I would expect db2 to have analytic functions and CTEs, so perhaps:
with
basedata as (
select t.*
, sum(t.price) over(partition by t.supplierid) sum_price
from products t
)
select *
from basedata
where supplierid = ?
and sum_price > 50
The analytic function aggregates the price information but does not group the resultset, so you get the rows from your initial result, but restricted to those with an aggregated price value > 50.
The difference to a solution with a subquery is, that the use of the analytic function should be more efficient since it has to read the table only once to produce the result.
I'm implementing pagination on my BD. My problem is when I want limit the SELECT statement but not the JOIN. Example, a product can got many prices:
SELECT * FROM product
LEFT JOIN price ON product.id == price.id_product
LIMIT 20
But I want to get 20 products with each one with their prices. How I can limit the statement SELECT, but not LEFT JOIN.
Example:
product price.id price.id_pruct price.price
1 1 1 50
2 2 1 30
3 3 1 40
4 1 20
5 2 30
SELECT * FROM product
LEFT JOIN price ON product.id == price.id_product
LIMIT 3
Return:
product price.id id_prodcut price
1 1 1 50
1 2 1 30
1 3 1 40
But I Want
product price.id id_prodcut price
1 1 1 50
1 2 1 30
1 3 1 40
1 4 1 20
2 5 2 30
3 . . .
Three products (limit 3)
Thanks. I hope you can help me.
Modify your query to limit the number of product rows before joining it to the price table. This means we want to to join the results of a query to a table, or in other words, we write a query containing a subquery:
SELECT *
FROM (
SELECT *
FROM product
ORDER BY id_product
LIMIT 3
) p
LEFT JOIN price ON p.id = price.id_product
Hope that helps.
I would write a subquery to get the three first products (or whatever condition you choose) like this:
SELECT id
FROM product
ORDER BY id
LIMIT 3;
Once I have that, I can select everything from the price table as long as the id is in that subquery. You can do this using a join:
SELECT p.*
FROM price p
JOIN(
SELECT id
FROM product
ORDER BY id
LIMIT 3) tmp ON tmp.id = p.product_id;
Here is an SQL Fiddle example using your sample data, and I also added a row that won't be returned so you can see that it works.
I have tables as follow:
A deliveries
delveryid clientid deliverydate
1 10 2015-01-01
2 10 2015-02-02
3 11 2015-04-08
B items in deliveris
itemid deliveryid qty status
70 1 5 1
70 1 8 2
70 2 10 1
72 1 12 1
70 3 100 1
I need to add a column to my query that gives me the qty of each part in other deliveris of the same client.
meaning that for given data of client 10 and delivery id 1 I need to show:
itemid qty status qtyOther
70 5 1 10 //itemid 70 exists in delivery 2
70 8 2 10 //itemid 70 exists in delivery 2
72 12 1 0 //itemid 72 doesn't exists in other delivery of client 11
Since I need to add qtyOther to my existing qry i'm trying to avoid using Group By as it's a huge query and if I use SUM in select I will have to group by all items in select.
This is what I have so far:
Select ....., coalesce( SUM(a.qty) OVER (PARTITION BY a.itemid) ,0) AS qtyOther
FROM B b
LEFT JOIN A a USING
LEFT JOIN (other tables)
WHERE clientid=10 ....
This query gives me the total sum of qty per itemid for specific clientid, regardless of which delivery it is. How do I change it so it will consider the delivryid? I need something like:
coalesce( SUM(a.qty) OVER (PARTITION BY a.itemid) FROM B where deliveryid<>b.deliveryid ,0) AS qtyOther
Any suggestions how to do that?
Note: I can NOT change the condition in WHERE.
I think you just want to subtract out the total for the current delivery:
Select .....,
(coalesce( SUM(a.qty) OVER (PARTITION BY a.itemid), 0) -
coalesce( SUM(a.qty) OVER (PARTITION BY a.itemid, a.deliveryid), 0)
) as qtyOther