Re: updating rows which have a common value forconsecutive dates

You need to turn the query with the window function into a sub-query and then in the outer query you can refer to the inner-query's rank() column. The inner query should effectively get you the last two test results for each context and then you can check to see if any of those failed.

I have a hunch you might need a third layer of sub-queries to handle the failure aspect of the requirement properly; possibly as part of a "WITH" CTE. You for sure need to in order to. Properly utilize the rank() function limiting.

Dave

On Apr 14, 2011, at 0:52, Lonni J Friedman <netllama(at)gmail(dot)com> wrote:

> Hi David,
> Thanks for your reply. I'm using 8.4.7, so window functions are
> certainly an option, although I've admittedly never used them before.
> I've spent the past few hours reading the dox, and I now have a
> rudimentary understanding of window functions. I tried to compose a
> query based on your suggestion, but I think i'm running up against my
> lack of experience. This query seems to give me all failures but not
> neccesarily when there are two in a row for a unique group (although
> I'm still not 100% certain its actually returning only last_update
> consecutive rows):
> SELECT testname,os,arch,build_type,branch,current_status,last_update,rank()
> OVER (PARTITION BY testname,os,arch,branch,build_type ORDER BY
> last_update DESC) FROM mytable WHERE current_status='FAILED' AND
> age(now(),last_update) <= INTERVAL '15 days'
>
> However, if I'm understanding how this works, what I really care about
> is when a rank=2 exists, as that's truly when something failed for two
> consecutive last_update's. I thought this might do it, but apparently
> I'm doing it wrong:
>
> SELECT testname,os,arch,build_type,branch,current_status,last_update,rank()
> OVER (PARTITION BY testname,os,arch,branch,build_type ORDER BY
> last_update DESC) FROM mytable WHERE current_status='FAILED' AND
> age(now(),last_update) <= INTERVAL '15 days' AND rank()=2 ;
> ERROR: window function call requires an OVER clause
> LINE 1: ... age(now(),last_update) <= INTERVAL '15 days' AND rank()=2 ;
>
> How do I restrict the results to only show when rank=2 ?
>
> thanks!
>
>
> On Wed, Apr 13, 2011 at 9:57 AM, David Johnston <polobo(at)yahoo(dot)com> wrote:
>> If you have the ability to use Window functions you can group (as necessary), order by last_update, and then use rank() to number each test run sequentially. Then you can limit the results to ( rank() <= 2 AND current_status = 'FAILED' ).
>>
>> David J.
>>
>> -----Original Message-----
>> From: pgsql-general-owner(at)postgresql(dot)org [mailto:pgsql-general-owner(at)postgresql(dot)org] On Behalf Of Lonni J Friedman
>> Sent: Wednesday, April 13, 2011 3:34 AM
>> To: pgsql-general
>> Subject: [GENERAL] updating rows which have a common value forconsecutive dates
>>
>> Greetings,
>> I have a table full of automated test data, which continuously has new unique data inserted:
>>
>> Column | Type |
>> Modifiers
>> ----------------+-----------------------------+-------------------------
>> ----------------+-----------------------------+-------------------------
>> ----------------+-----------------------------+-----------
>> id | integer | not null default
>> nextval('dbltests_id_seq'::regclass)
>> testname | text | not null
>> last_update | timestamp without time zone | not null default now()
>> current_status | text | not null
>> os | text | not null
>> arch | text | not null
>> build_type | text | not null
>> branch | text | not null
>>
>> The 'testname' column contains many different tests, and each unique 'testname' has numerous different associated os,arch,build_type & branch values. For example, testname='foo' will run on os='Linux',arch='i686',build_type='debug',branch='t38', and also on os='Windows7',arch='x86_64',build_type='release',branch='r40', etc, and there will be many other different testname's with similar permutations of the os,arch,build_type & branch columns. So for example, there will also be testname='bar' or testname='omega' or testname='sigma' for the other assorted os,arch,build_type & branch permutations.
>>
>> The current_status column is either 'PASSED' or 'FAILED'.
>>
>> What I'm struggling with is how to put together a SQL query which shows me all instances of a given testname permutation
>> (os,arch,build_type,branch) which has a current_status value of 'FAILED' for two or more most recent consecutive 'last_update' values.
>>
>> Suggestions welcome.
>>
>> thanks in advance!
>
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