Solved

select, group by, having clauses

Posted on 2002-06-04
8
304 Views
Last Modified: 2012-08-14
Hello,

I would need help with the GROUP BY and HAVING clauses.

Suppose I have the following table: mytable

field1   field2
------   ------
a        1
a        2
a        2
b        1
b        2
b        3
c        1
c        2

First I want to select those rows such that field1 is repeated 3 times:

   SELECT *
   FROM mytable
   WHERE field1 in (SELECT field1
                    FROM mytable
                    GROUP BY field1
                    HAVING count(*) = 3)

The result must be:

field1   field2
------   ------
a        1
a        2
a        2
b        1
b        1
b        1

Then I would like to select from this set those rows such that field2 is "2" twice:

The result should be:

field1   field2
------   ------
a        1
a        2
a        2

But... I don not know how to build a statement to achieve this, which includes the GROUP BY clause.

Thanks in advance,

juarrero


0
Comment
Question by:juarrero
[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
  • 2
  • 2
  • +2
8 Comments
 
LVL 5

Expert Comment

by:spcmnspff
ID: 7054359
Try this . . .


Select *
from MyTable
Where Field2 In

 ( Select T1.Field2
   From (SELECT *
         FROM mytable
         WHERE field1 in (SELECT field1
                          FROM mytable
                          GROUP BY field1
                          HAVING count(*) = 3)) T1
   Group By T1.field2 Having Count(T1.*) = 2)
0
 
LVL 69

Expert Comment

by:Scott Pletcher
ID: 7054964
I don't think comparing only on field2 will work :=(.  Maybe try this:

SELECT myTable.*
FROM myTable
INNER JOIN
(SELECT field1
 FROM myTable
 GROUP BY field1
 HAVING COUNT(*) = 3)
AS t1 ON myTable.field1 = t1.field1
INNER JOIN
(SELECT field2
 FROM myTable t2
 WHERE t1.field1 = t2.field1
 GROUP BY field2
 HAVING COUNT(*) = 2)
AS t3 ON myTable.field1 = t3.field1 AND myTable.field2 = t3.field2

Running short on time.  Will try to further verify this query later.
0
 

Expert Comment

by:Mogalappa Adaki
ID: 7055395
your question is not understandable, can you elaborate again clearly your requirement?
0
Why You Need a DevOps Toolchain

IT needs to deliver services with more agility and velocity. IT must roll out application features and innovations faster to keep up with customer demands, which is where a DevOps toolchain steps in. View the infographic to see why you need a DevOps toolchain.

 
LVL 5

Expert Comment

by:sachin_raorane
ID: 7056349
in your first result u have given
field1 field2
------ ------
a      1
a      2
a      2
b      1
b      1
b      1

in case of "a" is ok, but how you will get

b      1
b      1
b      1

when there is no such data in table

please check your requirment again
0
 
LVL 69

Expert Comment

by:Scott Pletcher
ID: 7056427
I suspected that it was just a "typo" and that he meant to repeat the original data, like so:

b   1
b   2
b   3

Since no value appears twice, "b" should not be selected.

0
 
LVL 5

Accepted Solution

by:
sachin_raorane earned 300 total points
ID: 7061174
As i said there is no data like you want in first result, so i doubt you can form such query.

for the second result following Query will work

select * from mytable
where field1 in(
     select field1
     from mytable
     where field2 in
          (select field2 from mytable
          group by field2
          having count(*)>=2)
     group by field1
     having count(*) = 3)
0
 

Author Comment

by:juarrero
ID: 7156763
Sorry for the long delay...

Effectively there is a typo, the first result in my query should be:

field1 field2
------ ------
a      1
a      2
a      2
b      1
b      2
b      3

Then, the desired query should be more or less like the proposed one:

select * from mytable
where field2 in(
    select field2
    from mytable
    where field1 in
         (select field1 from mytable
          group by field1
          having count(*)=3)
    group by field2
    having count(*) = 2)

Thanks and sorry again

juarrero
0
 

Author Comment

by:juarrero
ID: 7156766
Sorry for the large delay...

Effectively there is a typo, the first result should be:

field1 field2
------ ------
a      1
a      2
a      2
b      1
b      2
b      3

Then, the desired query should be more or less like the proposed one:

select * from mytable
where field2 in(
    select field2
    from mytable
    where field1 in
         (select field1 from mytable
          group by field1
          having count(*)=3)
    group by field2
    having count(*) = 2)

Thanks and sorry again

juarrero
0

Featured Post

Instantly Create Instructional Tutorials

Contextual Guidance at the moment of need helps your employees adopt to new software or processes instantly. Boost knowledge retention and employee engagement step-by-step with one easy solution.

Question has a verified solution.

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

Suggested Solutions

Ever needed a SQL 2008 Database replicated/mirrored/log shipped on another server but you can't take the downtime inflicted by initial snapshot or disconnect while T-logs are restored or mirror applied? You can use SQL Server Initialize from Backup…
Recently we ran in to an issue while running some SQL jobs where we were trying to process the cubes.  We got an error saying failure stating 'NT SERVICE\SQLSERVERAGENT does not have access to Analysis Services. So this is a way to automate that wit…
Familiarize people with the process of utilizing SQL Server functions from within Microsoft Access. Microsoft Access is a very powerful client/server development tool. One of the SQL Server objects that you can interact with from within Microsoft Ac…
Via a live example, show how to set up a backup for SQL Server using a Maintenance Plan and how to schedule the job into SQL Server Agent.

738 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