[postgis-users] Doubts dissolving geometries

[Rémi Cura]

otherwise, you can use an aggregate function on the id field.
For instance min(emt_paradas.id)
This is not a postgis problem, but a sql problem ;-)
Cheers,
Rémi-C

2014-11-26 19:47 GMT+01:00 Nicolas Ribot <nicolas.ribot at gmail.com>:

> Hi,
>
> You can generate an id on-the-fly:
>
> SELECT 1 as id, ST_union(st_buffer(emt_paradas.geom, 500)) FROM
> emt_paradas
>
> Nicolas
>
> On 26 November 2014 at 19:14, Luís Miguel Royo Pérez <
> luis.miguel.royo at gmail.com> wrote:
>
>>  Hi everyone,
>>
>> I'm trying to make a quite simple query in Postgis but I have problems
>> with it. I just want to create a buffer dissolved of a set of points. Only
>> that.
>>
>> This is the query I'm using:
>>
>> SELECT  emt_paradas.id , ST_union(st_buffer(emt_paradas.geom, 500)) FROM
>> emt_paradas
>>
>> but when I try to execute this, tells me the field  emt_paradas.id must
>> be in the clause group by but if I do that, the dissolve is not done.
>>
>> I'm in the DBManager of QGIS 2.6. I want to create this layer and load it
>> in the canvas, for that DBManager asks me for an ID field, that's why I
>> added emt_paradas.id in the select. If i remove it, Postgis creates the
>> geometrybut I can't load it in the canvas.
>>
>> Any help or guidance will be apreciate.
>>
>> Thanks a lot!!
>>
>>
>>
>>
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>
>
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