Solved

Get max date from sql query

Posted on 2007-11-26
4
4,871 Views
Last Modified: 2008-02-01
I need to combine both these queries to get the max date if they have a entry in either the table.  This is part of a much larger query, but I am wondering how to combine these.  Thanks

'contactdate'=(Select max(dtmcontact) FROM tblMHCPContact B  where A.lngpatientid=B.lngpatientid and A.lngtype = @type  and dtmcontact between dateadd(day, -7, getdate()) and getdate()),        
       
 'encounterdate'=(Select Max(visitdate) FROM tblMHCPencounter B  where A.lngpatientid=B.lngpatientid  and visitdate between dateadd(day, -7, getdate()) and getdate()),          
0
Comment
Question by:running32
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 8

Accepted Solution

by:
digital_thoughts earned 500 total points
ID: 20352749
You should be able to use a subquery similar to the below:

SELECT
      MAX(VarDate)
FROM
(
      Select
            dtmcontact AS VarDate
      FROM
            tblMHCPContact B  
      where
            A.lngpatientid=B.lngpatientid
            and A.lngtype = @type  
            and dtmcontact between dateadd(day, -7, getdate()) and getdate()
      UNION
      Select
            visitdate AS VarDate
      FROM
            tblMHCPencounter B  
      where
            A.lngpatientid=B.lngpatientid  
            and visitdate between dateadd(day, -7, getdate())
            and getdate()
)
0
 
LVL 35

Expert Comment

by:David Todd
ID: 20354171
Hi,

A couple of observations on the above query

1.
What is the table alias A?

2.
Suggest using Union All instead of Union. Union implies distinct, which removes duplicate rows. This process involves a sort and a filter. The distinct operation doesn't add anything to this query except extra time and cost.

HTH
  David
0
 
LVL 8

Expert Comment

by:digital_thoughts
ID: 20395758
Any luck on your problem?
0
 

Author Comment

by:running32
ID: 20464468
Yes, thanks I have it working.  
0

Featured Post

Learn by Doing. Anytime. Anywhere.

Do you like to learn by doing?
Our labs and exercises give you the chance to do just that: Learn by performing actions on real environments.

Hands-on, scenario-based labs give you experience on real environments provided by us so you don't have to worry about breaking anything.

Question has a verified solution.

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

In database programming, custom sort order seems to be necessary quite often, at least in my experience and time here at EE. Within the realm of custom sorting is the sorting of numbers and text independently (i.e., treating the numbers as number…
'Between' is such a common word we rarely think about it but in SQL it has a very specific definition we should be aware of. While most database vendors will have their own unique phrases to describe it (see references at end) the concept in common …
This video Micro Tutorial shows how to password-protect PDF files with free software. Many software products can do this, such as Adobe Acrobat (but not Adobe Reader), Nuance PaperPort, and Nuance Power PDF, but they are not free products. This vide…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…

707 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