So I have a current sqlite db table that contains the following:
Set Name
Set ID
Set Price
List of Items included in JSON
I am getting in a shopping list of items wanted from front end. Each Set could contain one or more of the items in the list, as well as items not on the list. How would I be able to find the cheapest way of obtaining the list of items by buying the right amount of sets, allowing for purchasing multiple sets to get all of the items on the provided list?
Example:
Set A contains 2 apples, 5 bananas, and 5 croissants. Costs $3
Set B contains 6 apples, 10 bananas, and 2 croissants. Costs $7
List: Need 10 bananas and 2 croissants. -- Result: Buy 2 Set As
List Need 15 bananas -- Result: Buy 3 Set As
List: Need 12 apples -- Buy 2 Set Bs
Currently just sorting the results by lowest price and adding the quantities of the list of items within the JSON together. Thinking there should be a more efficient way, may have to redesign the tables to allow for direct querying of the list of items, but the size of the list for each set can be different, and the request list can be of different items. Thinking this problem has probably already been solved, but also don't know what it's called or what the solutions are.
Related
I have a Cognos report that has four different sections/layouts, each containing their own list. I would like to use one section to perform calculations using another list from another section. Is that possible?
For example:
Section Two contains a list with Name, Week1 Commissions, Week2 Commissions, etc
I want Section One to calculate the first 11 weeks only so the List in Section One would contain
Name, Weeks 1 through 11 total.
What is the best way to make this happen if it's possible.
Section One would contain these columns which would perform the calculations
Name Week 1-11 totals |
Section Two would have these columns
Name Week 1 Week 2 Week 3 .....
Best,
Kev
Yes it is possible, and you can perform all of the logic in one query
There are many ways to do this
For example, the four different sections/layouts, selecting the list, go to properties you can use the same query for each list
I work for an eCommerce company and we use Microsoft Excel for our inventory database. We currently just keep adding items to this database as we purchase them, without ever removing them. What I would like to do is start removing items as they sell. I am not sure how to attach the file, so if you e-mail me at drenollet#supplykick.com I can send it to you. Below are the following steps:
The Sales tab includes the sales data for the items. I would like to take this data and be able to copy and paste it in a sheet in our Inventory Managment file in excel (a separate file, but I included a sample in the "Database" sheet).
I then need to just use a VLOOKUP formula and the Catalog data to get the Product ID instead of the SKU. (I can do this.)
Then use the copied data in the Sales Tab that is in the Inventory Management file and move the corresponding rows out of the Database file/sheet to the Sold Items sheet.
A few thoughts on specifics:
I want to make sure all the quantities are right. (e.g.1 if we purchased two of an item and only one sold - reducing the quantity in the Database sheet from two down to one.) (e.g.2 If we purchased an item two different times at two different prices and both were purchased in one sale, I would want to make sure both of the rows are moved out of the database).
If you have any thoughts on making sure the quantities are right, let me know. Maybe we need to set all the purchase quantities to one and copy the purchase of a multiple quantity of items X number of times for each one that was purchased.
Would love your input on how to cross this bridge! Let me know if you would like to see the sample file and I can directly e-mail it to you!
Best Regards,
Don Renollet
The best way to do this is to have a sheet called Movements
then you have just rows of entries like
A B C D
----------------------------------------
prodID Movement type Qty Date
123 Purchase 5 08/01/15
789 Sale 2 07/01/15
123 Return 1 06/01/15
456 Sale 1 05/01/15
789 Purchase 10 04/01/15
456 Purchase 5 03/01/15
123 Sale 2 03/01/15
123 Return 1 02/01/15
123 Sale 1 02/01/15
123 Purchase 10 01/01/15
Then at anytime excel can calculate whats in stock using sumifs or similar
=SUMIFS(C:C,A:A,"123",B:B,"Purchase") - Sumif(C:C,A:A,"123",B:B,"Sale")) + Sumif(C:C,A:A,"123",B:B,"Return"))
You should never remove rows from a database like this, you can always do a stock take every so often and restart the database with 1 entry for each item, but aways store the old data elsewhere.
Try not to mix price with quantity if possible, if you need to manage price , consider using a moving average price (MAP)
The task here is to define the optimal (as detailed below) way of ordering items (parts) from suppliers.
The relevant parts of the table schema (with some sample data) are
Items
ID NUMBER
1 Item0001
2 Item0002
3 Item0003
Suppliers
ID NAME DELIVERY DISCOUNT
1 Supplier0001 0 0
2 Supplier0002 0 0.025
3 Supplier0003 20 0
DELIVERY is the delivery charge (in dollars) levied by that supplier on each delivery. DISCOUNT is the settlement discount (as a percentage i.e. 2.5% for ID=2 above) allowed by that supplier for on time payment.
SupplierItems
SUPPLIER_ID ITEM_ID PRICE
1 2 21.67
1 5 45.54
1 7 32.97
This is the many-to-many join between suppliers and items with the price that supplier charges for that item (in dollars). Every item has at least 1 supplier but some have more than one. A supplier may have no items.
PartsRequests
ID ITEM_ID QUANTITY LOCATION_ID ORDER_ID
1 59 4 2 (null)
2 89 5 2 (null)
3 42 4 2 (null)
This table is a request from a field site for parts to be ordered and delivered by the supplier to that site. A delivery of any number of items to a site attracts a delivery charge. When the parts are ordered, the ORDER_ID is inserted into the table so we are only concerned with those where ORDER_ID IS NULL
The question is, what is the optimal way to order these parts for each `LOCATION' where there are 3 optimal solutions that need to be presented to the user for selection.
The combination of orders with the least number of suppliers
The combination of orders with the lowest total cost i.e. The sum of QUANTITY*PRICE for each item plus the DELIVERY for each order summed over all orders ignoring DISCOUNT
As item 2 but accounting for DISCOUNT
Clearly I need to determine the combinations of orders that are available and then determining the optimal ones becomes trivial but I am a bit stuck on an efficient way to deal with building the combinations.
I have built some SQL fiddles in SQL Server 2008 with random data. This one has 100 items, 10 suppliers and 100 requests. This one has 1000 items, 50 suppliers and 250 requests. The table schema is the same.
Update
I reasoned that the solution had to be recursive and I built a nice table valued function to get but I ran into the 32 hard limit on recursion in SQL Server. I was uncomfortable with it anyway because it hinted more of a procedural language solution than a RDMS.
So I am now playing with CTE recursion.
The root query is:
SELECT DISTINCT
'' SOLUTION_ID
,LOCATION_ID
,SUPPLIER_ID
,(subquery I haven't quite worked out) SOLE_SUPPLIER
FROM PartsRequests pr
INNER JOIN
SupplierItems si ON pr.ITEM_ID=si.ITEM_ID
WHERE pr.ORDER_ID IS NULL
This gets all the suppliers that can supply the required items and is certainly a solution, probably not optimal. The subquery sets a flag if the supplier is the sole supplier of any product required for that location; if so they must be part of any solution.
The recursive part is to remove suppliers one by one by means of CTE.SUPPLIER_ID<>CTE.SUPPLIER_ID and add them if they still cover all the items. The SOLUTION_ID will be a CSV list of the suppliers removed, partly to uniquely identify each solution and partly to check against so I get combinations instead of permutations.
Still working on the details, the purpose of this update was to allow the Community to say "Yay, looks like that will work" or, alternatively "You moron, that won't work because ..."
Thanks
This is a more general answer (as in, not sql) as I think solving this problem will require something more powerful. Your first scenario is to select a minimum number of suppliers. This problem can be seen as a set cover problem as you are trying to cover all demands per site with the suppliers. This problem is already NP-complete.
Your third scenario seems to be basically the same as the second. You just have to take the discount into account in the prices, assuming you pay on time for every order.
The second scenario is at least NP-hard as I see a lot of resemblance with the facility location problem. You are trying to decide which suppliers (facilities) to use (open) to cover your orders (demands) based on their prices and delivery costs (opening costs).
Enumerating your possible solutions seems infeasible as with 10 suppliers, you have 2^10 possibilities of using them, further complicated by the distribution of demands internally.
I would suggest some dynamic programming to first select the suppliers that you have to use (=they are the only ones that deliver a specific thing), eliminating some possibilities (if the cost for supplier A +delivery cost A< cost for supplier B) and then trying to expand your set of possible solutions. Linear programming is also a valid train of thought.
I have 2 almost identical tables like this example:
item_list
store item price
-------------------------
store1 SKU2388 200
store1 SKU2377 150
season_list
store item price season_start season_end
-------------------------------------------------------
store1 SKU2377 100 12/10/10 31/12/10
store1 SKU2310 300 12/10/10 31/01/11
There will be multiple stores, and sometimes with multiple seasonal items specific to some stores that only available once in a time then disappears, and won't make it to normal items list. There will also be some normal items with promotional price on specific period.
Now, how can I make a compilation of these 2 tables, with all prices from normal items, combined with all seasonal items, and if there are some conflicting items, the query will return the one on season_list and discard those on item_list?
Thank you for your help :)
select COALESCE(seasonal.price,normal.price)
from normal left outer join seasonal
on normal.id= seasonal.id
column and table name is not what you mentioned but hope to get the idea.
It joins two tables and when the seasonal price in not exists or is null it returns the normal price.
I have an ecommerce store that I am building. I am using Rails/ActiveRecord, but that really isn't necessary to answer this question (however, if you are familiar with those things, please feel free to answer in terms of Rails/AR).
One of the store's requirements is that it needs to represent two types of products:
Simple products - these are products that just have one option, such as a band's CD. It has a basic price, and quantity.
Products with variation - these are products that have multiple options, such as a t-shirt that has 3 sizes and 3 colors. Each combination of size and color would have its own price and quantity.
I have done this kind of thing in the past, and done the following:
Have a products table, which has the main information for the product (title, etc).
Have a variants table, which holds the price and quantity information for each type of variant. Products have_many Variants.
For simple products, they would just have one associated Variant.
Are there better ways I could be doing this?
I worked on an e-commerce product a few years ago, and we did it the way you described. But we added one more layer to handle multiple attributes on the same product (size and color, like you said). We tracked each attribute separately, and we had a "SKUs" table that listed each attribute combination that was allowed for each product. Something like this:
attr_id attr_name
1 Size
2 Color
sku_id prod_id attr_id attr_val
1 1 1 Small
1 1 2 Blue
2 1 1 Small
2 1 2 Red
3 1 1 Large
3 1 2 Red
Later, we added inventory tracking and other features, and we tied them to the sku IDs so that we could track each one separately.
Your way seems pretty flexible. It would be similar to my first cut.