I'm close, but I cannot seem to figure out this SQL query. I've got the SELECT and related FROM tables right, but I think my subquery structure is messed up.
Question: Compose an SQL statement to generate a list of two least expensive vendors (suppliers) for each raw material. In the result table, show the following columns: material ID, material description, vendor ID, vendor name, and the supplier's unit price. Sort the result table by material ID and supplier’s unit price in ascending order. Note: If a raw material has only one vendor (supplier), that supplier and its unit price for the raw material should also be in the result (output) table.
Here's what I've got:
SELECT Supplies_t.Material_ID, Raw_Materials_t.Material_Description,
Vendor_t.Vendor_ID, Vendor_t.Vendor_name, Supplies_t.Unit_price
FROM Supplies_t S1, Raw_Materials_t, Vendor_t
WHERE Vendor_t.Vendor_ID = Supplies_t.Vendor_ID
AND Supplies_t.Material_ID = Raw_Materials_t.Material_ID
AND Supplies_t.Unit_price IN
(SELECT TOP 2 Unit_price
FROM Supplies_t S2
WHERE S1.Material_ID = S2.Material_ID
ORDER BY S2.Material_ID ASC, S2.Unit_price ASC)
Using the correct table aliases may solve your problem. You should also use explicit JOIN syntax:
SELECT s.Material_ID, rm.Material_Description, v.Vendor_ID, v.Vendor_name, s.Unit_price
FROM (Supplies_t s INNER JOIN
Raw_Materials_t rm
ON s.Material_ID = rm.Material_ID
) INNER JOIN
Vendor_t v
ON v.Vendor_ID = s.Vendor_ID
WHERE s.Unit_price IN (SELECT TOP 2 s2.Unit_price
FROM Supplies_t s2
WHERE s.Material_ID = s2.Material_ID
ORDER BY s2.Material_ID ASC, s2.Unit_price ASC
);
Related
I'm trying to build an SQL query where I grab one table's information (WHERE shops.shop_domain = X) along with the COUNT of the customers table WHERE customers.product_id = 4242451.
The shops table DOES NOT have product.id in it, but the customers table DOES HAVE the shop_domain in it, hence my attempt to do some sort of join.
I essentially want to return the following:
shops.id
shops.name
shops.shop_domain
COUNT OF CUSTOMERS WHERE customers.product_id = '4242451'
Here is my not so lovely attempt at the query.
I think I have the idea right (maybe...) but I can't wrap my head around building this query.
SELECT shops.id, shops.name, shops.shop_domain, COUNT(customers.customer_id)
FROM shops
LEFT JOIN customers ON shops.shop_domain = customers.shop_domain
WHERE shops.shop_domain = 'myshop.com' AND
customers.product_id = '4242451'
GROUP BY shops.shop_id
Relevant database schemas:
shops:
id, name, shop_domain
customers:
id, name, product_id, shop_domain
You are close. The condition on customers needs to go in the ON clause, because this is a LEFT JOIN and customers is the second table:
SELECT s.id, s.name, s.shop_domain, COUNT(c.customer_id)
FROM shops s LEFT JOIN
customers c
ON s.shop_domain = c.shop_domain AND c.product_id = '4242451'
WHERE s.shop_domain = 'myshop.com'
GROUP BY s.id, s.name, s.shop_domain;
I am also inclined to include all three columns in the GROUP BY, although Postgres (and ANSI/ISO standards) are happy with just id if it is declared as the primary key in the table.
A correlated subquery should be substantially cheaper (and simpler) for the purpose:
SELECT id, name, shop_domain
, (SELECT count(*)
FROM customers
WHERE shop_domain = s.shop_domain
AND product_id = 4242451) AS special_count
FROM shops s
WHERE shop_domain = 'myshop.com';
This way you only need to aggregate in the subquery, and need not worry about undesired effects on the outer query.
Assuming product_id is a numeric data type, so I use a numeric literal (4242451) instead of a string literal '4242451' - which might cause problems otherwise.
I am trying to get related products but the issue which I'm facing is that there is product photos table which has one-to-many relationship with products table, so when I get products by matching category Id it also returns multiple product photos with that product which i do not want. I want only one product photo from product photos table of specific product. Is there any way to use distinct in joins or any other way? what I have done so far....
SELECT [Product].[ID],
,[Thumbnail]
,[ProductName]
,[Model]
,[SKU]
,[Price]
,[IsExclusive]
,[DiscountPercentage]
,[DiscountFixed]
,[NetPrice]
,[Url]
FROM [dbo].[Product]
INNER JOIN [ProductPhotos] ON [ProductPhotos].[ProductID]=[Product].[ID]
INNER JOIN [ProductCategories] ON [ProductCategories].[ProductID]=
[Product].[ID]
WHERE [ProductCategories].[CategoryID]=4
And the result I am getting is...
Product Photos table has
Is there any way to use distinct or group by on product Id column in product photos table to return only one row from photos table.
Instead of using inner join, use cross apply:
SELECT . . .
FROM dbo.Product p CROSS APPLY
(SELECT TOP (1) pp.*
FROM ProductPhotos pp
WHERE pp.ProductID = p.id
ORDER BY NEW_ID()
) pp INNER JOIN
ProductCategories pc
ON pc.ProductID = p.id
WHERE pc.CategoryID = 4;
Notes:
The ORDER BY NEWID() chooses a random photo. You can order by specific columns to get the earliest, latest, biggest, or whatever.
Note that I added table aliases. These make the query easier to write and to read.
You should qualify all column names in your query, so it is clear which tables they come from.
I removed the superfluous square braces. They just make the query harder to write and to read.
You can use ROW_NUMBER() to return one row for ProductID, like this:
JOIN (SELECT *,
ROW_NUMBER() OVER (PARTITION BY ProductID ORDER BY PhotoID) rn
FROM [ProductPhotos]) [ProductPhotos]
ON [ProductPhotos].[ProductID]=[Product].[ID] AND [ProductPhotos].rn = 1
Instead of this:
JOIN [ProductPhotos] ON [ProductPhotos].[ProductID]=[Product].[ID]
you can use sub query in join with distinct instead of joining table directly.
you can create alias and use that column as distinct in select statement, but it will create performance issues when having loads of data inside.
if you have 3 different photos for same product Id (like 2). you can use sub-query with top 1 order by PK desc to get latest picture.
I have a script that updates an ID field on one table where that record matches to another table based on criteria.
Below is the general structure of my query.
update p.saleId = e.saleId
from products p inner join sales s on s.crit1 = p.crit1
where p.someDate between s.startDate and s.endDate
This is working fine. My issue is that in some situations there is more than one match on the 'sales' table with this query which is generally ok. I'd however like to sort these results based on another field to make sure the saleId I get is the one with the highest cost.
Is that possible?
As it is the saleID you want to set and the sales table you are looking up, you can probably just update all products records. Then you can write a simple update statement on the table and don't have to join. This makes this much easier to write:
update products p
set saleId =
(
select top(1) s.saleId
from sales s
where s.crit1 = p.crit1
and p.someDate between s.startDate and s.endDate
order by cost desc
);
The main difference to your statement is that mine sets saleId = NULL where there is no match in the sales table, while your lets these untouched. But I guess that doesn't make a difference here.
I hope the below query may solve. Wrote very high level draft as per your question. Please take only the concept not the syntax.
with maxSales as (select salesId, crit1 from sales s1
where cost = (select max(cost) from
sales s2 where s1.crit1 = s2.crit1)
update products p set p.saleId =
(select s.saleId from
maxSales s
where s.crit1 = p.crit1
and p.someDate between s.startDate and s.endDate)
UPDATE p
set p.saleId = e.rowNumber
FROM products p
INNER JOIN
(SELECT saleId, row_number() OVER (ORDER BY saleId DESC) as rowNumber
FROM sales)
e ON e.saleId = p.saleId
TRY THIS:
UPDATE p
SET p.saleid = s.saleid
FROM products p
INNER JOIN
(SELECT s.crit1,
s.saleid
FROM sales s
WHERE cost IN
(SELECT max(cost) cost
FROM sales
GROUP BY crit1)) s ON s.crit1 = p.crit1
None of the answers worked, but I managed to do it by using and Outer Apply as my join, and specified the sort order in that.
Cheers everyone for the input.
I keep getting the wrong sum value when I join 3 tables.
Here is a pic of the ERD of the table:
(Original here: http://dl.dropbox.com/u/18794525/AUG%207%20DUMP%20STAN.png )
Here is the query:
select SUM(gpCutBody.actualQty) as cutQty , SUM(gpSewBody.quantity) as sewQty
from jobOrder
inner join gpCutHead on gpCutHead.joNum = jobOrder.joNum
inner join gpSewHead on gpSewHead.joNum = jobOrder.joNum
inner join gpCutBody on gpCutBody.gpCutID = gpCutHead.gpCutID
inner join gpSewBody on gpSewBody.gpSewID = gpSewHead.gpSewID
If you are only interested in the quantities of cuts and sews for all orders, the simplest way to do it would be like this:
select (select SUM(gpCutBody.actualQty) from gpCutBody) as cutQty,
(select SUM(gpSewBody.quantity) from gpSewBody) as sewQty
(This assumes that cuts and sews will always have associated job orders.)
If you want to see a breakdown of cuts and sews by job order, something like this might be preferable:
select joNum, SUM(actualQty) as cutQty, SUM(quantity) as sewQty
from (select joNum, actualQty, 0 as quantity
from gpCutBody
union all
select joNum, 0 as actualQty, quantity
from gpSewBody) sc
group by joNum
Mark's approach is a good one. I want to suggest the alternative of doing the group by's before the union, simply because this can be a more general approach for summing along multiple dimensions.
Your problem is that you have two dimensions that you want to sum along, and you are getting a cross product of the values in the join.
select joNum, act.quantity as ActualQty, q.quantity as Quantity
from (select joNum, sum(actualQty) as quantity
from gpCutBody
group by joNum
) act full outer join
(select joNum, sum(quantity) as quantity
from gpSewBody
group by joNum
) q
on act.joNum = q.joNum
(I have kept Mark's assumption that doing this by joNum is the desired output.)
I have two tables with a many to one relationship which represent lots and bids within an auction system. Each lot can have zero or more bids associated with it. Each bid is associated with exactly one lot.
My table structure (with irrelevant fields removed) looks something like this:
For one type of auction the winning bid is the lowest unique bid for a given lot.
E.g. if there are four bids for a given lot: [1, 1, 2, 4] the lowest unique bid is 2 (not 1).
So far I have been able to construct a query which will find the lowest unique bid for a single specific lot (assuming the lot ID is 123):
SELECT id, value FROM bid
WHERE lot = 123
AND amount = (
SELECT value FROM bid
WHERE lot = 123
GROUP BY value HAVING COUNT(*) = 1
ORDER BY value
)
This works as I would expect (although I'm not sure it's the most graceful approach).
I would now like to construct a query which will get the lowest unique bids for all lots at once. Essentially I want to perform a JOIN on the two tables where one column is the result of something similar to the above query. I'm at a loss as to how to use the same approach for finding the lowest unique bid in a JOIN though.
Am I on the wrong track with this approach to finding the lowest unique bid? Is there another way I can achieve the same result?
Can anyone help me expand this query into a JOIN?
Is this even possible in SQL or will I have to do it in my application proper?
Thanks in advance.
(I am using SQLite 3.5.9 as found in Android 2.1)
You can use group by with a "having" condition to find the set of bids without duplicate amounts for each lot.
select lotname, amt
from lot inner join bid on lot.id = bid.lotid
group by lotname, amt having count(*) = 1
You can in turn make that query an inline view and select the lowest bid from it for each lot.
select lotname, min(amt)
from
(
select lotname, amt
from lot inner join bid on lot.id = bid.lotid
group by lotname, amt having count(*) = 1
) as X
group by X.lotname
EDIT: Here's how to get the bid id using this approach, using nested inline views:
select bid.id as WinningBidId, Y.lotname, bid.amt
from
bid
join
(
select x.lotid, lotname, min(amt) as TheMinAmt
from
(
select lot.id as lotid, lotname, amt
from lot inner join bid on lot.id = bid.lotid
group by lot.id, lotname, amt
having count(*)=1
) as X
group by x.lotid, x.lotname
) as Y
on Y.lotid = bid.lotid and Y.TheMinAmt = Bid.amt
I think you need some subqueries to get to your desired data:
SELECT [b].[id] AS [BidID], [l].[id] AS [LotID],
[l].[Name] AS [Lot], [b].[value] AS [BidValue]
FROM [bid] [b]
INNER JOIN [lot] [l] ON [b].[lot] = [l].[id]
WHERE [b].[id] =
(SELECT TOP 1 [min].[id]
FROM [bid] [min]
WHERE [min].[lot] = [b].[lot]
AND NOT EXISTS(SELECT *
FROM [bid] [check]
WHERE [check].[lot] = [min].[lot]
AND [check].[value] = [min].[value]
AND [check].[id] <> [min].[id])
ORDER BY [min].[value] ASC)
The most inner query (within the exists) checks if there are no other bids on that lot, having the same value.
The query in the middle (top 1) determines the minimum bid of all unique bids on that lot.
The outer query makes this happen for all lots, that have bids.
SELECT lot.name, ( SELECT MIN(bid.value) FROM bid Where bid.lot = lot.ID) AS MinBid
FROM Lot INNER JOIN
bid on lot.ID = bid.ID
If I understand you correctly this will give you everylot and their smallest bid