title: How to produce "merge" of two data sets with select SQL statement (Oracle DBMS)?
body: <p>What would be the insert SQL statement to merge data from two tables.  For example I have events_source_1 table (columns: event_type_id, event_date) and events_source_2 table (same columns) and events_target table (columns: event_type_id, past_event_date nullalbe, future_event_date nullable).</p>
  
  <p>Events_source_1 has past events, Events_source_2 has future events and resultant events_target would contain past and future events in the same row for same event_type_id. If there is no past_events but future_events then past_event_date won't be set and only future_event_date will be and the opposite is true too.  </p>
  
  <p>Thanks a lot in advance for helping me resolving this problem.</p>