RE: Limiting SQL results returned -- MIDRANGE-L

Jim,

Off the top of my head....

With T1 as (select status, infoField, rand() as randomNbr
from filename
),
With T2 AS (SELECT Status,
InfoField,
ROW_NUMBER() over (PARTITION BY Status ORDER BY Status, randomNbr) as Nbr
from T1 ORDER BY Status )

SELECT * FROM T2 WHERE Nbr < 6

Sorry, don't have v5r4 to test against.

HTH,
Charles

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Jim Essinger
Sent: Tuesday, July 31, 2007 7:02 PM
To: Midrange Systems Technical Discussion
Subject: Re: Limiting SQL results returned

This list is great!

Elvis

Thanks for pointing me in the right direction.

After doing it the hard way, this worked for me;

With T1 AS (SELECT Status,
InfoField,
ROW_NUMBER() over (PARTITION BY Status ORDER BY Status) as Nbr
from FileName ORDER BY Status )

SELECT * FROM T1 WHERE Nbr < 6

Any thoughts on how to get a random 5 selected instead of the first 5?

Thanks again.

Jim

On 7/31/07, Elvis Budimlic
<ebudimlic@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Looks like ROW_NUMBER would work. Try this in Run Sql Scripts if
you're on
V5R4:

SELECT * FROM
(SELECT A.*,
ROW_NUMBER() OVER(PARTITION BY status ORDER BY

status) AS RN

FROM myfile A) B
WHERE RN IN (1,2,3,4,5)

or using common table expression:

WITH CTE AS
(SELECT A.*,
ROW_NUMBER() OVER(PARTITION BY status ORDER BY

status) AS RN

FROM myfile A)
SELECT * FROM CTE WHERE RN IN (1,2,3,4,5)

NOTE: It errored out on my system, but we're way behind on

db fixpacks.

Elvis

Celebrating 10-Years of SQL Performance Excellence
http://centerfieldtechnology.com/training.asp

-----Original Message-----
Subject: RE: Limiting SQL results returned

Scratch that syntax, I just realized it won't work. Try

this instead

WITH CTE1 AS
(SELECT * FROM MYFILE WHERE STATUS = 'status 1' FETCH FIRST 5 ROWS
ONLY),
CTE2 AS
(SELECT * FROM MYFILE WHERE STATUS = 'status 2' FETCH FIRST 5 ROWS
ONLY),
CTE3 AS
(SELECT * FROM MYFILE WHERE STATUS = 'status 1' FETCH FIRST 5 ROWS
ONLY), ......
SELECT * FROM CTE1
UNION ALL
SELECT * FROM CTE2
UNION ALL
SELECT * FROM CTE3
....

Ugly, I know.

Celebrating 10-Years of SQL Performance Excellence
http://centerfieldtechnology.com/training.asp

-----Original Message-----
Subject: RE: Limiting SQL results returned

Brute force it by running something like:

SELECT * FROM MYFILE WHERE STATUS = 'status 1' FETCH FIRST

5 ROWS ONLY

UNION ALL SELECT * FROM MYFILE WHERE STATUS = 'status 2'

FETCH FIRST 5

ROWS ONLY UNION ALL SELECT * FROM MYFILE WHERE STATUS = 'status 1'
FETCH FIRST 5 ROWS ONLY ......

and do it as many times as you have unique statuses in your

table (you

said about 20 or so).

I haven't used new RANK, PARTITION and recursive CTEs yet

so I'm not

sure if there is more elegant way to address this.
I'd be curious to see one as well.

Elvis

-----Original Message-----
Subject: Limiting SQL results returned

SQL Guru's

Is there a way to limit the number of rows returned from a

SQL statement?

For instance, I want a sampling of 5 records for each

status from a file.

Status, Fn1, .... Fn6

For _each_ status that appears in the file, I want 5 and only 5
resulting rows, could be the first 5 or last 5 or a random 5 -
although a random 5 would be awesome - would help with

another project I have ahead of me.

There could be 20 different status codes in the file, and I

want 5 records

for all 20 status codes. I guess that there might not be

5 for some

statuses, so getting up to 5 results would be OK too.

Any thoughts?

Jim

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