I have two PostgreSQL tables :
table_a (polygon) with field_1 table_b (polygon) with field_2
For field 2, I would like to get the corresponding value in field_2 of the polygons of table 2 inside or touching polygons of table_a
So far I was using a default expression in QGIS :
field_2 = aggregate ('table_a','concatenate',"field_a",intersects ($geometry,geometry(@parent)),',',"field_a")
but I would like to create the same result using the default value inside PostgreSQL directly.