Solved

MS SQL - How do I fetch the same column twice from one table?

Posted on 2009-07-02
11
582 Views
Last Modified: 2012-08-14
Hi,

I have two tables. One has a full list of IDs with their descriptions, the other lists the relationship between the IDs. I realise this sounds a little cryptic so I'll try and illustrate it in the code section.

What I need to do is have a full list of IDs with their parent and child descriptions...see desired result table in the coding section.
Table 1:
ID     Descr
1      James
2      Philip
3      Peter
4      Allan
 
Table 2:
ID     ChildID
1      2
1      3
2      NULL
3      4
4      NULL
 
Desired Result:
ID    ParentDescr     ChildDescr
1     James               Philip
1     James               Peter
2     Philip                 NULL
3     Peter                 Allan
4     Allan                 NULL

Open in new window

0
Comment
Question by:joshgeake
[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
  • 4
  • 3
  • 2
  • +1
11 Comments
 
LVL 59

Expert Comment

by:Kevin Cross
ID: 24765175
Something like this should work:
select p.ID, p.Descr AS ParentDescr, c.Descr AS ChildDescr
from Table1 p
inner join Table2 pc ON pc.ID = p.ID
left join Table1 c ON pc.ChildID = c.ID

Open in new window

0
 
LVL 2

Author Comment

by:joshgeake
ID: 24765194
thanks, my issue was how to query the same table twice for the descriptions of the child and parent IDs but it looks like this sorts it - i'll comment tomorrow when i'm back in the office.

thanks again!
0
 
LVL 17

Expert Comment

by:pssandhu
ID: 24765212
Select c.ID, C.Desc ParentDescr, m.ChildID, m.Descr as ChildDescr
From Table1 c INNER JOIN (
Select a.ID, a.ChildID, t.Descr
From  Table1 t INNER JOIN  Table2 d
           ON t.ID = ChildID
Where ChildID IS NOT NULL) as m
ON c.ID = m.Id
0
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.

 
LVL 17

Expert Comment

by:pssandhu
ID: 24765226
I am really slow today... :-)
0
 
LVL 23

Expert Comment

by:Racim BOUDJAKDJI
ID: 24765481

Alternatively...Something like this should work...
select ALL.*
from
(
select A.id, A.Descr as ParentDescr, C.Descr as ChildDescr from table1 A inner join table2 B on  A.id = B.id inner join table1 C on B.ChildID = C.id where B.ChildID is not null
union all
select A.id, A.Descr, NULL from table1 A inner join table2 B on  A.id = B.id where B.ChildID is null
) ALL
order by ALL.id

HTH
0
 
LVL 2

Author Comment

by:joshgeake
ID: 24771302
Right i'm still a little stuck, see the code snippet...

It looks like its listing all part groups for every product when what I want it to do is only list its relevent group. Each part can be in a number of product groups but it's usually 1. Thus it will then list the child group.

Any ideas?
SELECT     epar.part AS PartCode, p.prod_group, c.prod_group AS child_group, p.descr AS ParentDescr, c.descr AS ChildDescr
FROM         epar LEFT OUTER JOIN
                      wgrp_part ON epar.part = wgrp_part.part INNER JOIN
                      wgrp AS p ON wgrp_part.prod_group = p.prod_group INNER JOIN
                      wgrp_sgrp AS pc ON pc.Prod_group = p.prod_group LEFT OUTER JOIN
                      wgrp AS c ON pc.sub_group = c.prod_group
WHERE     (c.descr IS NOT NULL)
ORDER BY epar.part

Open in new window

0
 
LVL 2

Author Comment

by:joshgeake
ID: 24771319
by the way...
epar - lists all parts.
wgrp_part - lists all parts and their prod_groups.
wgrp_sgrp - lists all sub_groups and their respective prod_group.
wgrp - lists all prod_groups and sub_groups descriptions.
0
 
LVL 17

Expert Comment

by:pssandhu
ID: 24772162
Sorry, but I am a little confused. Can you please post some sample data from the tables we can work with?
P.
0
 
LVL 59

Accepted Solution

by:
Kevin Cross earned 250 total points
ID: 24975302
The way (including table structure) the question was asked, it was answered here - http:#24765175.

However, the asker changed things up here - http:#24771302 for which additional information was requested here - http:#24772162 that was never responded to; therefore, would recommend "delete - no refund" unless my original answer will be honored.
0
 
LVL 17

Expert Comment

by:pssandhu
ID: 25013765
I would recommend accepting mvisa's answer since it was answered based on what was requested.
P.
0

Featured Post

Secure Your Active Directory - April 20, 2017

Active Directory plays a critical role in your company’s IT infrastructure and keeping it secure in today’s hacker-infested world is a must.
Microsoft published 300+ pages of guidance, but who has the time, money, and resources to implement? Register now to find an easier way.

Question has a verified solution.

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

Suggested Solutions

Why is this different from all of the other step by step guides?  Because I make a living as a DBA and not as a writer and I lived through this experience. Defining the name: When I talk to people they say different names on this subject stuff l…
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…

749 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