The DISTINCT 'ON' clause is not supported but I am trying to see if there are other people who have run into this. One of the use cases I have intuitively maps to something like this:
SELECT DISTINCT *ON (a)*, b, c FROM T Here suppose 'a' is an INT and b, c are some complex types such as array. In my example, the values of b and c happen to be the same in all rows belonging to the same group of 'a', so I just want the first row. Since these are arrays, I cannot use MIN(b) GROUP BY a . Other alternative is to create a new aggregate function that picks the first value but it makes the syntax verbose especially with large number of such columns. Incidentally, Postgres supports this [1] [1] https://www.postgresql.org/docs/current/static/sql-select.html#SQL-DISTINCT -Aman
