Currently there appears to be only one way for a sql operator to be
unparsed.
This is a problem for operations that look different depending on the
dialect currently used.
A good example is "FLOOR(datetime to timeUnit)"
In postgres this is: date_trunc('year', my_datetime)
In hsqldb: TRUNC ( my_datetime, 'YYYY' )
In oracle: TRUNC(my_datetime, 'YEAR')
In mysql: There's no direct equivalent in mysql
Right now if this would break if executed against a jdbc datasource, since
the sql generated just contains the "FLOOR(...".
I'm sure there must be other sql functions that also require similar
dialect switching.
I think it would be nice to be able to override the sql operator unparse
method on a dialect basis.
Right now the sql writer takes a dialect argument, but that's really just
for quoting and small formatting differences. The unparse method of every
operator could take a dialect argument, but I think there's probably a
better way.
Has anyone had any similar ideas and know how this could be approached?
