Consider the following scenario, run directly in isql:

select 'hello' AS
THIS_IS_A_VERY_LONG_FIELD_NAME_FAR_TOO_LONG_FOR_PRACTICAL_USE from
rdb$database;

returns the following:

THIS_IS_A_VERY_LONG_FIELD_NAME_
===============================

hello

While we all know there's a 32 character limit on field names, it silently
applies to aliases as well...
I got trapped when using PHP:

$sql = "select 'hello' AS
THIS_IS_A_VERY_LONG_FIELD_NAME_FAR_TOO_LONG_FOR_PRACTICAL_USE from
rdb\$database";
$rec = ibase_query($sql);
$obj = ibase_Fetch_object($rec);
echo $obj->THIS_IS_A_VERY_LONG_FIELD_NAME_FAR_TOO_LONG_FOR_PRACTICAL_USE;

...this returned nothing, no error messages, nothin, but...:

echo $obj->THIS_IS_A_VERY_LONG_FIELD_NAME_

...works just fine.
Just thought it's worth letting people know the fix...