I threw together a Fiddle that demonstrates it here[1]. It shows the basic single column version, a multi-column distinct on, and an example that uses a case st

I threw together a Fiddle that demonstrates it here[1]. It shows the basic single column version, a multi-column distinct on, and an example that uses a case statement for a derived column. The only thing with the third example is that I don't believe you can alias the derived column within the distinct on field itself, so have to repeat the expression - once within the distinct on and again in the column list of the select statement. [1] https://www.db-fiddle.com/f/7CCYFf14UtkuGYfGZAt5PY/3 https://www.db-fiddle.com/f/7CCYFf14UtkuGYfGZAt5PY/3