Concatenate Rows Grouping By Categories

Question

I'm having an attribute table like this of a shapefile on QGIS:

Movie / Actor

A / 1

A / 2

A / 3

B / 4

I want to get the name of a movie and all actors in that movie, and I want the result to be in a format like this:

Movie / ActorList

A / 1, 2, 3

B / 4

How can I do it?

Which kind of geoprocessing are you thinking to modify the attribute table grouping observations like this? — aldo_tapia, Commented Aug 2, 2017 at 18:53
We do this in PostgreSQL using the string_agg() function... I think is similar to the QGIS aggregate function though I can't seem to figure out how to get it to work — Inactivated Account, Commented Aug 2, 2017 at 19:02
The table ahead is just an example. I want to dissolve a feature based on the categoriy (MOVIE) and create a new column with all the other attributes concatenated (ActorsList). The real situation is that i have multiple polygons with the category CITIES and the attributes like FOREST, URBAN AREAS, ETC. I want to dissolve with the field CITIES and bring in another column all the attributes of the original shapefile. — Daniel Grisotto, Commented Aug 3, 2017 at 18:37
Welcome to gis.stackexchange! Please note that a good question on this site is expected to show some degree of research on your part, i.e. what you have tried and - if applicable - code so far. For more info, you can check our faq. — underdark, Commented Feb 16, 2019 at 18:11

Kazuhito · Accepted Answer · 2019-02-16 14:21:23Z

4

As DPSSpatial commented, QGIS aggregate function has concatenate().

Just make sure the Output field length is long enough.

Expression is: concatenate("Actor", group_by:="Movie", concatenator:=', ')

answered Feb 16, 2019 at 14:21

Kazuhito

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