Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Qatar to Latvia as you normally would.
The Qatar to Latvia flight path was viewed by 20 users in the past month. Keep an eye out for changes in search interest prior to high and low season.
These are just IATA (International Air Transport Association) codes. They are used in aviation to identify and differentiate airports. That’s why a Doha Hamad Intl Airport to Riga Intl Airport flight would often be abbreviated as a DOH to RIX flight. Liepāja Intl Airport (LPX) are other airports near this flight route and their unique identifiers/IATA codes.