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Using QGIS it is possible to easily label features from related tables with a 1 to 1 JOIN. If the relationship is one to many and Project Properties RELATIONS are defined, then only the last related entry seems to be available for labeling (this is only available if a JOIN is also defined). For example, if I have a feature set called Countries with field called Country as the related (key) field and a related table fields Country and Flag_Colors, how could I do a label like this: "Name: United States Colors: Red, White, Blue" I'm hoping since the Attribute Table Form has Expressions and the Feature ID panel both count and display the 3 colors (i.e. related records) there is some type of SQL expression that can get the kind of Feature label I am describing. See attached screen shot of the current limits of my labeling attempt.

Ay suggestions or ideas?

enter image description here

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  • Take a look at the relation_aggregate function with concatenate as the aggregation type.
    – Matt
    Commented Apr 17, 2023 at 6:07

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First, you need to create a relation between the two tables via "Project -> Properties->Relations": enter image description here

Next, you can use the following expression to label each country with all responding child features and their respective color:

 'Name: ' || "CNTRY_NAME"  || ' Colors: '|| relation_aggregate(relation:='Country_Colors',aggregate:='concatenate',expression:="Color", concatenator:=', ')

enter image description here

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  • Thanks to you all for helping with this one. I'd never heard of this call. but it did just what I was hoping for.
    – Zapper
    Commented Apr 18, 2023 at 13:13

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