Thanks for all that good stuff, Steve. One or two comments below.
Dave
Steve Lime wrote:
Dave: If these are numbers why are you treating them as strings? Straight string comparison of numbers can be unpredictable. Have you tried removing the quotes?
Drowning-man-clutching-at-straws syndrome! I think I'd tried every other
permutation before that.
Other options:
1) you can do the classification in PostGIS. Paul Ramsey's workshop materials
have some nice examples.
That's what I did thereafter. So I now have one layer for each
date-range with DATA definitions like:
DATA "geom from (select dr, geom, stdname, deddlo, deddhi,
oid from saintloc where ((deddlo >= 12010101) AND (deddlo <= 13001231))
OR ((deddhi >= 12010101) AND (deddhi <= 13001231))) as foo using srid=27700"
2) MapServer does support true dates in logical expressions. I believe you use
backtics to denote dates that way.
That said, I think you can just treat 'em as ints.
I did go back and try the EXPRESSION method again, but it seemed to
break down on nulls. E.g.
EXPRESSION ((([deddlo] >= 11010101) AND ([deddlo] <= 12001231))
OR (([deddhi] >= 11010101) AND ([deddhi] <= 12001231)))
worked OK if both deddlo and deddhi contained valid (integer) dates, but
not if either was null.
Steve
DjwStone <[EMAIL PROTECTED]> 05/12/06 8:52 AM >>>
I'm having difficulty setting up an EXPRESSION statement for a PostGIS layer.
The field being tested is a numeric representation of a date in YYYYMMDD
format so that ranges can be easily compared.
When the expression is (say):
EXPRESSION ('[fieldname]' ge '15010101')
everything works fine; I get the correct number of hits. Similarly,
EXPRESSION ('[fieldname]' le '16001231')
works as it should.
However, when I have:
EXPRESSION ('[fieldname]' ge '15010101') and ('[fieldname]' le '16001231')
I get no hits although there should be some.
Has anyone else had similar problems?
Cheers,
Dave
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