Update a table and skip the conflicting rows/take some action.

dirty_updates.sql

DO $$
DECLARE r RECORD;
BEGIN
	FOR r IN <query that will return a record set for r to iterate over>
	LOOP 
		BEGIN  
			RAISE NOTICE 'Dealing with ID: %',r.id;
			UPDATE <table> as t1
			SET var1 = t2.var1 
			from <table2> t2
			WHERE <constraints>;
			
			--Exception handling
			EXCEPTION WHEN unique_violation THEN
			RAISE NOTICE 'Skipping conflict at: %', r.id;
			--Do something else
		END;    
	END LOOP;
END$$;