Re: Some insight on the proper SQL would be appreciated

Thank you so much Oliver. This also worked perfectly.

On 6/8/10 1:55 PM, "Oliveiros d'Azevedo Cristina"
<oliveiros(dot)cristina(at)marktest(dot)pt> wrote:

> Howdy, Aaron,
>
> For me this is not an easy question, specially when I don't have your data
> here on my PC to test.
>
> But as a first approach, try this query. It is designed to give you the
> oldest 5 entries.
> But, be aware that this is non-tested code. Be prepared for it to not work
> or even to contain sintax errors.
>
> Just tell me the results and we'll continue from there
>
> Best,
> Oliver
>
> SELECT a.username,a.firstname,a.lastname,a.signedup
> FROM t_YourTable a
> JOIN t_YourTable b
> ON a.username = b.username
> AND a.firstname = b.firstname
> AND a.lastname = b.lastname
> AND a.signedup >= b.signedup
> GROUP BY a.username,a.firstname,a.lastname,a.signedup
> HAVING COUNT(b.*) <= 5;
>
> ----- Original Message -----
> From: "Aaron Burnett" <aburnett(at)bzzagent(dot)com>
> To: <pgsql-sql(at)postgresql(dot)org>
> Sent: Tuesday, June 08, 2010 6:04 PM
> Subject: [SQL] Some insight on the proper SQL would be appreciated
>
>
>>
>> Greetings,
>>
>> Any help on this would be appreciated.
>>
>> I have a table which is a list of users who entered a contest. They can
>> enter as many times as they want, but only 5 will count. So some users
>> have
>> one entry, some have as many as 15.
>>
>> How could I distill this down further to give me a list that shows each
>> entry per user up to five entries per user? In other words, I need a
>> separate line item for each entry from each user up to the maximum of 5
>> rows
>> per user.
>>
>> Table looks like this:
>> username | firstname | lastname | signedup
>> --------------------------------------+-----------+-------------+-----------
>> -
>> ffc4bd0a-ccff-4203-a03c-4bd6b8c23a03 | Jean | Mathews |
>> 2010-03-13
>> ffc4bd0a-ccff-4203-a03c-4bd6b8c23a03 | Jean | Mathews |
>> 2010-05-07
>> ffc4bd0a-ccff-4203-a03c-4bd6b8c23a03 | Jean | Mathews |
>> 2010-06-06
>> ff8720d4-f808-4ee6-90e6-649872fdfa55 | Janis | Bunch |
>> 2010-03-12
>> ff48d89b-6afe-4ba0-8539-9683bec62c89 | Sandy | Yashnyk |
>> 2010-04-25
>> ff48d2a4-0637-4e46-9461-3dd0dc0d4d83 | Kendra | Elliott |
>> 2010-05-09
>> ff3a2a14-2575-44d5-b40b-3780f4d2506a | Kay | Maher |
>> 2010-04-20
>> fef7625b-d1e1-4c1a-bc82-d35a4a6db16d | Carolyn | Woodul |
>> 2010-04-05
>> fef21bbb-07a0-4c84-8708-4dc41b8b770b | Laurie | Montijo |
>> 2010-04-03
>> feee6473-af4d-4e70-b20c-a74ba08c000f | Geneva | Anderson |
>> 2010-04-03
>> feb690fc-0afb-4e87-b0d1-bdb2c4603fd1 | Judith | Astroff |
>> 2010-06-05
>> fea0f9a6-e89f-4dbd-b3fd-83efed27221f | Jennifer | Lavigne |
>> 2010-02-09
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-03-20
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-03-27
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-04-03
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-04-10
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-04-17
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-04-25
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-05-01
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-05-08
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-05-16
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-05-22
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-05-30
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-06-06
>> fe825a6d-6820-4282-b8e9-2e3cb9f660e8 | Susan | Stowe |
>> 2010-03-12
>> fe825a6d-6820-4282-b8e9-2e3cb9f660e8 | Susan | Stowe |
>> 2010-03-15
>>
>> But in John Smith's case where he has more than 5 entries, I would like
>> query results to limit him to just 5 entries to look like this:
>>
>> username | firstname | lastname | signedup
>> --------------------------------------+-----------+-------------+-----------
>> -
>> ffc4bd0a-ccff-4203-a03c-4bd6b8c23a03 | Jean | Mathews |
>> 2010-03-13
>> ffc4bd0a-ccff-4203-a03c-4bd6b8c23a03 | Jean | Mathews |
>> 2010-05-07
>> ffc4bd0a-ccff-4203-a03c-4bd6b8c23a03 | Jean | Mathews |
>> 2010-06-06
>> ff8720d4-f808-4ee6-90e6-649872fdfa55 | Janis | Bunch |
>> 2010-03-12
>> ff48d89b-6afe-4ba0-8539-9683bec62c89 | Sandy | Yashnyk |
>> 2010-04-25
>> ff48d2a4-0637-4e46-9461-3dd0dc0d4d83 | Kendra | Elliott |
>> 2010-05-09
>> ff3a2a14-2575-44d5-b40b-3780f4d2506a | Kay | Maher |
>> 2010-04-20
>> fef7625b-d1e1-4c1a-bc82-d35a4a6db16d | Carolyn | Woodul |
>> 2010-04-05
>> fef21bbb-07a0-4c84-8708-4dc41b8b770b | Laurie | Montijo |
>> 2010-04-03
>> feee6473-af4d-4e70-b20c-a74ba08c000f | Geneva | Anderson |
>> 2010-04-03
>> feb690fc-0afb-4e87-b0d1-bdb2c4603fd1 | Judith | Astroff |
>> 2010-06-05
>> fea0f9a6-e89f-4dbd-b3fd-83efed27221f | Jennifer | Lavigne |
>> 2010-02-09
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-03-20
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-03-27
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-04-03
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-04-10
>> fea0334e-4ae1-4599-b24d-9a5d8ce4fd37 | John | Smith |
>> 2010-04-17
>> fe825a6d-6820-4282-b8e9-2e3cb9f660e8 | Susan | Stowe |
>> 2010-03-12
>> fe825a6d-6820-4282-b8e9-2e3cb9f660e8 | Susan | Stowe |
>> 2010-03-15
>>
>> The username is unique for each user.
>>
>> pg version 8.25 on RHEL
>>
>> Any help in this would be greatly appreciated.
>>
>> Thank you.
>>
>>
>> --
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>