[Qgis-user] Using expression dialog to access attributes from a relation.

Andrew McAninch andrew at rabbit-troop.net
Thu Dec 13 12:58:32 PST 2018


Yeah, You can do this with the relation_aggregate function. It aggregates values from all related records using a field or expression.  Ive only used the "concatenate" aggregate for returning strings from the related table but there are other options if you want to return an average, sum, string length, etc.   I think the help covers the use pretty well, but if you run into trouble I can give more specific help,

Andrew
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Thursday, December 13, 2018 8:11 AM, Andrew Bell <andrew at geoascent.com> wrote:

> I have spatial layer and non-spatial layer set up as a relation QGIS 3.4.  The non-spatial layer is the child.
>
> I'm trying create a display pop-up for the spatial layer that sources attributes and values from the relation layer.
>
> I can see the relation is an option in the expression dialog but at the moment I cannot see how I'm going to bring through field names and values from this other table.
>
> Has anyone done this and have any pointers they could share?
>
> Many thanks
>
> Andrew
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