Dear list members, maybe I am overlooking something. PostgreSQL offers UPSERT functionality by way of INSERT INTO ... ON CONFLICT ... DO UPDATE ...; Consider this pseudo-code schema table master pk_master serial primary key value text ; table detail pk_detail serial primary key fk_master int foreign key master(pk_master) detail text ; where there can be any number of rows in detail linking to a particular row in master, including none (master rows without details, that is). There will be a view giving rows for each detail row enriched with master table data UNION ALL rows for each master row that does not have any detail row with detail table columns NULLed What I want to achieve: Given a pk_detail (and pk_master) having been obtained from the view (therefore pk_detail being NULL or an integer value) UPDATE that detail row (namely when pk_detail is distinct from NULL) or insert a new detail row (when pk_detail IS NULL) linking that row to the master row identified by pk_master. I know I can do so from client code. I also know I can wrap this functionality inside a plpgsql function. I am wondering though whether it can be done as one SQL statement. It seems to me that would call for an UPDATE ... ON MISSING ... DO INSERT ...; or CASE WHEN pk_detail IS NULL THEN INSERT ... WHEN pk_detail IS DISTINCT FROM NULL THEN UPDATE ... END both of which don't exist/work, of course. So, is this doable within one SQL statement (short of creating and running the abovementioned function in one go ;-) ? (the real story is about medication and intake regimens / schedules thereof involving a whole lot more columns, of course, which should not be relevant to the problem though) Thanks for taking the time to read, Karsten -- GPG 40BE 5B0E C98E 1713 AFA6 5BC0 3BEA AC80 7D4F C89B
