hi there!
im absolute new with postgresql so i maybe ask very simle things - sorry for that :

i have two databases, one with headdata and one with detaildata (im not the creator and i cant change that).

now i have to join the detaildata with the corresponding headdata across the databases.

my idea is to dump all detaildata-tables in one big table (the structure of the tables is identical so that a union-query should work fine) and import them in the headdata-database.

how can i do that in a efficient way? or is there a better possibility to join the databases?