It has been a while since we have seen a puzzle so let us do a small puzzle today. Actually, this is a very simple puzzle if you have worked with SQL Server for a while. I got an email from one of the readers from the blog post and he wanted me to correct the following query which he had written. Well, I have been working with SQL Server for over 19 years and I often do not remember the syntax and have to look up online. Here is a very simple puzzle for you which involves Aggregate and Subquery.
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Puzzle – Aggregate and Subquery
Here is the query when we run against the AdventureWorks database, it gives us an error. Remember AdventureWorks database is a sample database and you can download and install AdventureWorks over here.
USE AdventureWorks2014 GO SELECT pch.StandardCost, p.ProductID FROM Production.ProductCostHistory pch INNER JOIN Production.Product p ON pch.ProductID = p.ProductID WHERE pch.StandardCost > AVG(p.StandardCost) GO
Now when you run the above query, it gives us the following error:
Msg 147, Level 15, State 1, Line 17
An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference.
Now here is your task, you need to help me to fix the above query. The hint to resolve the query is already in the blog post’s title and in the query error. You need to understand what my query is attempting to do and use the hint which is already pointed out to you. After you successfully fix the query it will produce the following results.
Rules
Well, there are no real rules, as long as you modify my query to get me above results. Please post your query in the comments section below before April 22, 2019. I will keep all the answers hidden till April 22, 2019 11:59:00 PM.
Winner
One Winner will get 1 free seat for my upcoming class, which is worth USD 1000.
SQL Server Performance Tuning Practical Workshop for EVERYONE
Date: April 23, 2019, Tuesday
8:00 AM Pacific Time | 11:00 AM Eastern Time
If you do not want to take part in the contest, you can directly register for the class here.
Update: April 23, 2019
The contest is closed and the winning Answer is here:
USE AdventureWorks2014 GO SELECT pch.ProductID, pch.StartDate,pch.EndDate, pch.StandardCost, pch.ModifiedDate FROM Production.ProductCostHistory pch INNER JOIN Production.Product p ON pch.ProductID = p.ProductID WHERE pch.StandardCost > p.StandardCost GO
There is no need for the AVG on the StandardCost as there will be always a single entry for the product. Even if you change the query with group by + having you will still see the query uses the simple join.
Congratulations to the winner Nicholas Månsson. He is very excited to join the SQL Server Performance Tuning Practical Workshop for EVERYONE.
Everyone who participated you got to solve this difficult puzzle so indirectly you are a winner (of knowledge) as well. This was an intense competition with over 500 comments.
Reference: Pinal Dave (https://blog.sqlauthority.com)
527 Comments. Leave new
Hi Pinal,
This is the answer
USE AdventureWorks2014
GO
SELECT pch.StandardCost, p.ProductID
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > AVG(p.StandardCost)
GROUP BY pch.StandardCost, p.ProductID HAVING
pch.StandardCost > AVG(p.StandardCost)
GO
Damn! I thought I had the CORRECT answer until I saw the comments by Dave! :-D
Patel, you can still try to find a correct solution.
When you will post the correct answer.
The correct answer is posted https://blog.sqlauthority.com/2019/04/17/sql-puzzle-correct-the-incorrect-query-win-price-worth-usd-1000-aggregate-and-subquery/#comment-2037344
waiting for your reply, Pinal, when you would be announce the winner
The winning answer is posted and the winner will be announced now.
Hi Pinal, I’m holding my nerves to see the answer :-) I didn’t use GROUP BY or HAVING clause but still eager to see the correct answer. Is the status still “Currently no one is selected” ? Do you think I can still try for correct answer ?
The winning answer is here https://blog.sqlauthority.com/2019/04/17/sql-puzzle-correct-the-incorrect-query-win-price-worth-usd-1000-aggregate-and-subquery/#comment-2037344
SELECT pch.*
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > p.StandardCost
SELECT pch.ProductID, Pch.StartDate ,Pch.EndDate ,pch.StandardCost,pch.ModifiedDate
FROM Production.ProductCostHistory pch
WHERE pch.StandardCost > (SELECT AVG(p.StandardCost) From Production.Product p Where p.ProductID =pch.ProductID group by p.productID)
Will that be the answer that silly then !?
USE AdventureWorks2014
GO
SELECT pch.StandardCost, p.ProductID
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > (select AVG(StandardCost) from Production.Product)
GO
USE AdventureWorks2014
GO
SELECT p.ProductID, pch.StartDate, pch.EndDate, pch.StandardCost, pch.modifieddate–, AVG(p.StandardCost)
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > (SELECT AVG(p.StandardCost) FROM Production.Product p where pch.ProductID = p.ProductID)
GO
GOT IT!
SELECT p.ProductID, StartDate, EndDate, pch.StandardCost, p.ModifiedDate
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > p.StandardCost
GO
Hi Pinal,
SELECT pch.StandardCost, p.ProductID
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > (SELECT AVG(StandardCost)
FROM Production.Product
WHERE ProductID = pch.ProductID
GROUP BY ProductID)
Cheers,
Mario
USE AdventureWorks2014
GO
SELECT
p.ProductId,
pch.startdate,
pch.enddate,
pch.StandardCost,
pch.ModifiedDate
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > (SELECT AVG(p1.StandardCost)
FROM Production.ProductCostHistory pch1
INNER JOIN Production.Product p1 ON pch1.ProductID = p1.ProductID and p1.ProductID = p.ProductID)
USE AdventureWorks2014
GO
SELECT
p.ProductId,
pch.startdate,
pch.enddate,
pch.StandardCost,
pch.ModifiedDate
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > (SELECT AVG(p1.StandardCost)
FROM Production.ProductCostHistory pch1
INNER JOIN Production.Product p1 ON pch1.ProductID = p1.ProductID and p1.ProductID = p.ProductID)
Hi
Below is Updated Query
SELECT a.ProductID,pch.StartDate, pch.EndDate, pch.StandardCost, pch.ModifiedDate
FROM
(SELECT p.ProductID, AVG(P.StandardCost) AS AVGSTDCOST
FROM Production.Product p
GROUP BY p.ProductID)A
INNER JOIN Production.ProductCostHistory pch ON A.ProductID=pch.ProductID
WHERE pch.StandardCost>a.AVGSTDCOST
Good Morning Pinal,
I have tried to find the solution for the given question.
Please find attached below SQL Select statement for your verification.
Could you please confirm it at your end.
USE AdventureWorks2014
GO
SELECT p.ProductID,
CAST(pch.StartDate AS DATETIME) AS startdate,
CAST(pch.EndDate AS DATETIME) AS enddate,
pch.StandardCost,
CAST(pCH.ModifiedDate AS DATETIME) AS ModifiedDate
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
GROUP BY p.ProductID,
CAST(pch.StartDate AS DATETIME),
CAST(pch.EndDate AS DATETIME),
CAST(pCH.ModifiedDate AS DATETIME),
PCH.StandardCost
HAVING pch.StandardCost > AVG(p.StandardCost)
GO
Thanks,
Krushna
As we are referring StandardCost from Product table, we will get the AVG StandardCost value of product same for every row in ProductCostHistory. So no need to apply AVG function. We will get the result by removing it from WHERE caluse
USE AdventureWorks2014
GO
SELECT pch.StandardCost, p.ProductID
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > (p.StandardCost)
GO
Hey…my answer was also correct. :)
Good to hear!
Hi All, the winning Answer is here:
There is no need of the AVG on the standardcost as there will be always a single entry for the product. Even if you change the query with group by + having you will still see the query uses the simple join.
The winner will be sent email in the next 10 minutes.
Hi Pinal,
My answer is also correct answer and waiting for your email to join the session.
Looking forward to get it soon to take my skills to next level.
Regards,
CS
Hi Chandra, the winner is already notified.
I think my answer is also correct.
Winner will be announced soon.
my answer us correct, Sir:)
The winner is being picked by volunteers
Hi All, the winning Answer is here:
There is no need of the AVG on the standardcost as there will be always a single entry for the product. Even if you change the query with group by + having you will still see the query uses the simple join.
Congratulations to the winner Nicholas Månsson. He is very excited to join the SQL Server Performance Tuning Practical Workshop for EVERYONE.
Everyone who participated you are winner as well, this was intense competition with over 500 comments.
Congratulations!
~ Pinal at SQLAuthority.com
Hi Pinal, I’d like to know if my answer is correct though I’ve not used AVG and INNER JOIN.
USE AdventureWorks2014
GO
SELECT pch.StandardCost, p.ProductID
FROM Production.ProductCostHistory pch
INNER JOIN Production.Product p ON pch.ProductID = p.ProductID
WHERE pch.StandardCost > (SELECT avg(subpch.StandardCost)
FROM Production.ProductCostHistory subpch
INNER JOIN Production.Product subp ON subpch.ProductID = subp.ProductID)
Mera number kab aayega
The winner is already notified.