[postgis-users] Problem with subselects

[David Blasby]

The find_srid('','population','the_geom') function looks in
geometry_columns to find the SRID of the geometry.  If you're using
subselects you *must* use the "using SRID=xxxx" clause!

My bet is that the find_srid('','population','the_geom') function is
returning NULL (it cannot find the SRID in the geometry_columns table).
That would make the && function always return null, and you'll get a blank
map back.  geometry_columns should be automagically maintained if you use
AddGeometryColumn() and DropGeometryColumn().

I dont know why mappostgis.c isnt throwing an error when you try to do this
type of DATA statement.  Could you send me your actual map file?

dave