Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

Derived Table Problem

Posted on 2008-10-10
4
Medium Priority
?
465 Views
Last Modified: 2013-12-24
I am trying to use a derived table as part of a query in informix. I am tring to show the maximum date from it.

I keep getting error messages, which are not helpful i.e. Unknown error message number '-201'

select a.activity_date
from
(select casact.caseid, max(casact.activity_date)
from arista01:student1.casact casact
group by casact.caseid) a

Does anybody know the correct syntax for the above query?

Thanks
0
Comment
Question by:halifaxman
[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 60

Expert Comment

by:Kevin Cross
ID: 22695259
I am not Informix inclined; however, from a straight SQL Syntax point of view, the:
max(casact.activity_date)

Does NOT automatically retain column name of activity_date.  This is an expression, so you are going to get an untitled column or Expr1 or something to that effect.  Then in your outer query you are wanting to call by name activity_date, so you will need to do something like this:
max(casact.activity_date) AS activity_date

That will alias the expression back to a column name of activity_date.
0
 
LVL 60

Accepted Solution

by:
Kevin Cross earned 2000 total points
ID: 22695269
Here is a nice blog post on the subject.  It shows amongst other things that you are define the columns in the alias for the derived table itself.

e.g.
a(caseid, max_activity_date)

Will make more sense, when you read this:
http://informix-technology.blogspot.com/2007/06/cheetah-spot-by-spot-derived-tables-in.html
0
 

Author Comment

by:halifaxman
ID: 22698525
Thanks for the answers, I will have a look at what you suggest
0

Featured Post

Visualize your virtual and backup environments

Create well-organized and polished visualizations of your virtual and backup environments when planning VMware vSphere, Microsoft Hyper-V or Veeam deployments. It helps you to gain better visibility and valuable business insights.

Question has a verified solution.

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

In this series, we will discuss common questions received as a database Solutions Engineer at Percona. In this role, we speak with a wide array of MySQL and MongoDB users responsible for both extremely large and complex environments to smaller singl…
Instead of error trapping or hard-coding for non-updateable fields when using QODBC, let VBA automatically disable them when forms open. This way, users can view but not change the data. Part 1 explained how to use schema tables to do this. Part 2 h…
Video by: Steve
Using examples as well as descriptions, step through each of the common simple join types, explaining differences in syntax, differences in expected outputs and showing how the queries run along with the actual outputs based upon a simple set of dem…
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…
Suggested Courses

604 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