I am looking for a sort of spatial (un)join function.
Let's say I have 2 tables, both with a large number of polygons. The first one has a pop/polygon column in his attribute table. The 2nd one has smaller polygons that fit exactly into the bigger ones has a sum (these polygons represent census limitations).
Is there a function under QGIS or PostGreSQL that would separate the population/polygon from the 1st table into the smaller polygons of the 2nd table.
Example of the situation and end result: ID1 of table_1 has a population of 4. ID1, ID2, ID3 and ID4 of table_2 fit into ID1 of table_1. The function would create a population column into table_2 where ID1, 2, 3 and 4 each have a population of 1.
In other words I am looking for a function to do the exact opposite of the "Join attributes by location" in QGIS.