On sön, 2011-01-02 at 12:47 +0100, Florian Pflug wrote: > > Here's a patch to add support for negative index values in fetching > > elements from an array. > > That won't work. In SQL, array indices don't necessarily start with 0 (or 1, > or *any* > single value).
FYI, this is true for PostgreSQL, but not in SQL in general. In the standard, array indexes go from 1 to N. > The only way around that would be to introduce magic constants "lower", > "upper" that > can be used within index expressions and evaluate to the indexed dimension's > lower > and upper bound. You'd then use > > my_array[upper], my_array[upper-1], ... > > to refer to the last, second-to-last, ... element in the array. Actually > doing this > could get pretty messy, though - not sure if it's really worth the effort... How about just some functions: array_first(array, dim) array_last(array, dim) Perhaps some variants for splice vs. scalar. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
