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
Solved

Help with using a case statement within a union

Posted on 2011-09-08
2
236 Views
Last Modified: 2012-05-12
I am trying to modify a query so that I get different output depending on a specific value in one of the fields.  The query is something I found elsewhere and modified it to output a list of classes by course groups - like:

Group 100
 class 101
 class 102

Group 200
 class 201
 class 202

etc.

Now I need to have a different display only when the group level is 600 it will show something like:

Group 100
 class 101
 class 102

Group 200
 class 201
 class 202

Group 600
 no classes

I know I need a case but can't figure out how to incorporate that into my existing query - though I've been trying.  In the real query, I"m building some HTML but I've eliminated that here for the sake of clarity.  Anything that gives me alternate output for the 600 level will give me enough to work with.  The original query is attached.

Many thanks in advance.

SELECT Description
FROM
(
SELECT g.groupNum, 0 AS classId, g.groupName AS Description
FROM tbl_AdultEd_ClassGroups g where g.groupDisplay=1
UNION ALL
SELECT c.groupNum, c.classID, c.className AS Description 
FROM tbl_AdultEd_Classes c 
where c.classDisplay=1 
) sub
ORDER BY groupNum, classId

Open in new window

0
Comment
Question by:saabStory
2 Comments
 
LVL 5

Accepted Solution

by:
zvytas earned 500 total points
ID: 36503386
Try the folliwing:

SELECT CASE WHEN classId <> 0 AND groupNum = 600 THEN 'no classes' ELSE Description  END AS Description
FROM
(
SELECT g.groupNum, 0 AS classId, g.groupName AS Description
FROM tbl_AdultEd_ClassGroups g where g.groupDisplay=1
UNION ALL
SELECT c.groupNum, c.classID, c.className AS Description
FROM tbl_AdultEd_Classes c
where c.classDisplay=1
) sub
ORDER BY groupNum, classId

I assumed level is stored in groupNum.
0
 

Author Closing Comment

by:saabStory
ID: 36504779
Perfect!  Thanks so much!!!
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
SQL, add where clause 5 23
Transact SQL - Frequency of Length of Distinct Values 3 24
Parse this column 6 24
Help With SQL Query 8 25
Load balancing is the method of dividing the total amount of work performed by one computer between two or more computers. Its aim is to get more work done in the same amount of time, ensuring that all the users get served faster.
For both online and offline retail, the cross-channel business is the most recent pattern in the B2C trade space.
Using examples as well as descriptions, and references to Books Online, show the documentation available for date manipulation functions and by using a select few of these functions, show how date based data can be manipulated with these functions.
Viewers will learn how to use the UPDATE and DELETE statements to change or remove existing data from their tables. Make a table: Update a specific column given a specific row using the UPDATE statement: Remove a set of values using the DELETE s…

809 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