Solved

Retrieve corresponding field in group by query

Posted on 2014-01-13
3
125 Views
Last Modified: 2014-01-14
All, this should be so simple and yet I can't figure it out.  I have a table containing hourly volumes for a number of days (see excerpt below).

How do I write an access query that in addition to finding the maximum "totvol" for each day also returns the hour in which TotVol occurs?  So, from the table below I need to return two rows:
Day           Hour      TotVol
18-Jun-13      15      1563
19-Jun-13      5      1111

Retrieving the maximum TotVol value for each day is easy, but how do I get the associated hour?  

Here are the sample data:

Day           Hour      TotVol
18-Jun-13      15      1563
18-Jun-13      16      1481
18-Jun-13      17      1231
18-Jun-13      18      990
18-Jun-13      19      941
18-Jun-13      20      750
18-Jun-13       21      629
18-Jun-13      22      483
18-Jun-13      23      275
19-Jun-13      0      201
19-Jun-13      1      148
19-Jun-13      2      161
19-Jun-13      3      234
19-Jun-13      4      542
19-Jun-13      5      1111
0
Comment
Question by:mklik
3 Comments
 
LVL 30

Expert Comment

by:hnasr
ID: 39778409
Try:
Select [Day], [Hour], TotVol
From tbl
Where [TotVol] = (Select Max(TotVol) From tbl as tbl2 Where tbl.[Day]=tbl2.[Day] And tbl.[Hour]=tbl2.[Hour])

Open in new window

0
 
LVL 22

Accepted Solution

by:
Flyster earned 500 total points
ID: 39778432
You can do that with two queries. In the first query, add day and TotVol. In design view, select Totals. Set day to group and TotVol to Max. The sql look like this:

SELECT tblYourTable.Day, Max(tblYourTable.TotVol) AS MaxOfTotVol
FROM tblYourTable
GROUP BY tblYourTable.Day;

In a second query, add the first query and the table. Select the three fields you want from the table, Day, Hour, TotVol. Create a relation between TotVol in the table and MaxOfTotVol in the query. Here's the sgl:

SELECT tblYourTable.Day, tblYourTable.Hour, tblYourTable.TotVol
FROM tblYourTable INNER JOIN qryYourTable ON tblYourTable.TotVol=qryYourTable.MaxOfTotVol;

This should give you the result you want.

Flyster
0
 

Author Closing Comment

by:mklik
ID: 39780258
Thanks for offering your time to help me out--I tried both suggestions.  

Unfortunately, hnsar's code simply replicates the original table (tblYourTable)--not sure why,

Flyster's query comes very close, but it sometimes returns two rows for the same day, with different values for TotVol and Hour.  Once I joined the table and query on the day fields as well, I got the result I was looking for.

Thanks for pointing me in the right direction!
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Sharepoint 2013 Library List View Limitations 9 53
Oart.dll 2 45
How to get AD RMS to work with Office 2016 for Mac 6 163
Microsoft 365 versus MicroSoft 2013/2016 8 70
No matter the version of Windows you are using, you may have some problems with Windows Search running too slow or possibly not running at all. Before jumping into how you can solve this issue, just know there are many other viable alternative deskt…
In this article we discuss how to recover the missing Outlook 2011 for Mac data like Emails and Contacts manually.
The viewer will learn how to use a discrete random variable to simulate the return on an investment over a period of years, create a Monte Carlo simulation using the discrete random variable, and create a graph to represent the possible returns over…
The viewer will learn how to create two correlated normally distributed random variables in Excel, use a normal distribution to simulate the return on different levels of investment in each of the two funds over a period of ten years, and, create a …

861 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

25 Experts available now in Live!

Get 1:1 Help Now