[nmglug] query masters??

[Andres Paglayan]

On Fri, 2011-03-04 at 15:20 -0700, Bill York wrote:

> with the trailing ;
> 
> ---
> Bill York
> 762-233-7568
> 
> 
> 
> On Fri, Mar 4, 2011 at 2:53 PM, Bill York <iago at pobox.com> wrote:
> 
>         try this
>         
>         
>         
>         SELECT parent_id, question_id, Max(id) AS LastRecord FROM
>         xxYourTablexx GROUP BY parent_id, question_id HAVING
>         parent_id="1"
>         

yep,

since the table has a bunch of fields, and many are indexed and the
grouping wanted all indexes to be there, etc, etc,
I ended up running a first query exactly like that on those elements
only, (id, parent_id, question_id)

then mapping to the ids and retrieving the full records,
not super efficient, but kept the code clean and gets me exactly what i
needed,
(I am using active record as abstraction layer)


>         
>         
>         
>         ---
>         Bill York
>         762-233-7568
>         
>         
>         
>         
>         On Fri, Mar 4, 2011 at 2:48 PM, Andres Paglayan
>         <andres at paglayan.com> wrote:
>         
>                 
>                 Hey,
>                 
>                 I need a query for the following,
>                 
>                 given a table with this vales
>                 
>                 | id | parent_id | question_id |
>                 | 1  |  1             | 1                  |
>                 | 2  |  1             | 1                  |
>                 | 3  |  1             | 2                  |
>                 | 4  |  1             | 2                  |
>                 
>                 
>                 Knowing only that I am searching for the parent_id = 1
>                 I need a query that searches for
>                 parent_id = 1 and then for each matching record, the
>                 older entry,
>                 meaning the result should only have the records with
>                 id 2 and 4,
>                 
>                 any hint?
>                 
>                 
>                 
>                 
>                 
>                 
>                 
>                 
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>         
>         
>         
> 
> 
> 
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