Dear Erik, Thank you. But when i rerun the query with the edit (adding the closing parenthesis) :
*SELECT min(union_v4.max_hierar) as id, array_agg(union_v4.id <http://union_v4.id>) as ids, union_v6.geomFROM union_v4, (SELECT (ST_Dump(St_multi(ST_Union(geom)))).geom as geom FROM union_v6)WHERE st_intersects(union_v4.geom, union_v6.geom)GROUP BY union_v6.geom* *I obtain this time the message : * ERROR: la relation « union_v4 » n'existe pas LINE 5: FROM union_v4, ^ ERREUR: la relation « union_v4 » n'existe pas SQL state: 42P01 Character: 105 However, i have one table called "union_v4" within my postgis db. thanks so much. Le mar. 30 sept. 2025 à 17:04, Erik Wienhold <[email protected]> a écrit : > On 2025-09-30 16:08 +0200, celati Laurent wrote: > > I work with qgis and postgis. I would like to perform a "dissolve": > > > https://docs.qgis.org/3.40/en/docs/user_manual/processing_algs/qgis/vectorgeometry.html#dissolve > > > > in keeping/preserving all attributes values ? For instance : a kind of > > aggregation/concatenation within new "output features" ? > > > > I Saw this post : > > > https://www.aproposinfosystems.com/en/about/blog/managing-attributes-postgis-dissolve/ > > > > I have tried to reproduce the proposal with my postgis table containing > > several polygons > > > > *SELECT min(union_v4.max_hierar) as id, array_agg(union_v4.id > > <http://union_v4.id>) as ids, union_v6.geomFROM union_v4, (SELECT > > (ST_Dump(St_multi(ST_Union(geom)))).geom as geom FROM union_v6WHERE > > st_intersects(union_v4.geom, union_v6.geom)GROUP BY union_v6.geom* > > > > But i obtain : > > > > *ERROR: syntax error at the end of the entryLINE 12: GROUP BY > union_v6.geom > > ^ERROR: syntax error at the end of the entrySQL state: 42601Characters: > 285* > > Your query is missing the closing parenthesis of the union_v6 subquery > (after "FROM union_v6"). This should work: > > SELECT > min(union_v4.max_hierar) as id, > array_agg(union_v4.id) as ids, > union_v6.geom > FROM union_v4, > (SELECT > (ST_Dump(St_multi(ST_Union(geom)))).geom as geom > FROM union_v6) union_v6 > WHERE st_intersects(union_v4.geom, union_v6.geom) > GROUP BY union_v6.geom; > > -- > Erik Wienhold >
