[Qgis-user] Selecting records

[Phil Wyatt]

Thanks Pierma,

I can sort the dates no worries, so that should work. Many thanks.


Cheers - Phil, 
On the road with his iPad 

> On 30 Mar 2016, at 3:58 PM, Pierre-Marie Le Dantec <pierremarie.ledantec at gmail.com> wrote:
> 
> Hi Phil,
> 
> For manipulating dates throught SQL you should use ISO format ("YYYY-MM-DD").
> 
> Then, you can use a virtual layer with :
> 
> SELECT stationid, MAX(obs_date) FROM your_layer GROUP BY stationid
> 
> Cheers,
> 
> Pierma
> 
> 2016-03-30 13:09 GMT+11:00 Phil (The Geek) Wyatt <phil at wyatt-family.com>:
>> I must be thick, but I can't get my head around this in QGIS
>> 
>>  
>> 
>> Data
>> 
>> stationid_
>> 
>> obs_date
>> 
>> BK21
>> 
>> 28/03/2016
>> 
>> BK21
>> 
>> 29/03/2016
>> 
>> BK21
>> 
>> 30/03/2016
>> 
>> BL22
>> 
>> 28/03/2016
>> 
>> BL22
>> 
>> 29/03/2016
>> 
>> BL22
>> 
>> 30/03/2016
>> 
>> BL22
>> 
>> 31/03/2016
>> 
>>  
>> 
>>  
>> 
>> How do I select the Maximum date for each station ID?
>> 
>>  
>> 
>> The data will be coming from a GEOJSON feed but I can also pull it as a shape file if needs be
>> 
>>  
>> 
>>  
>> 
>> Cheers - Phil
>> 
>> 
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> 
> 
> 
> -- 
> Pierre-Marie Le Dantec
> 
> 73.64.34
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