Redshift interval literals seem to fail to parse

[maxcountryman]

Redshift's interval literals seem to differ in structure from what the parser presently expects. Notably, the date/time field is part of the preceding string. Perhaps the interval implementation could be modified to consider the Redshift implementation?

[nickolay]

This was intentional limitation of the initial implementation and there's a note to that effect in parser.rs. I don't see a reason why we can't change the parser to accept INTERVAL 'value' not followed by YEAR/HOUR/etc.

(I'm curious how Redshift parses select INTERVAL '1 day' DAY.)

[maxcountryman]

I'd be happy to take a look at this, @nickolay.

[nickolay]

@maxcountryman That's great to hear! And I will be happy to merge a PR from you:)