Re: Extracting single coordinate from a box

"Donald Fraser" <demolish(at)cwgsy(dot)net> writes:
> But when I try something like b[0][0] the passer ignores the second array
> subscript parameter and returns only a "point".

Try this:

regression=# select f1, (f1[1])[0] from box_tbl;
f1 | f1
---------------------+-----
(2,2),(0,0) | 0
(3,3),(1,1) | 1
(2.5,3.5),(2.5,2.5) | 2.5
(3,3),(3,3) | 3
(4 rows)

You need the extra parentheses because the two subscript operations need
to work on fundamentally different datatypes --- if you write f1[1][0]
you are asking to subscript a 2-D array which this isn't.

[ experiments further ... ] Drat, seems that syntax works in 7.4 but
not 7.3. Dunno if that will help you.

regards, tom lane