Fix the comparator when dealing with nulls.
Fix the comparator when dealing with nulls.

Turns out neither 'x' < 0 nor 'x' > 0.  However, 'x' > '0', and '0' < 5, and
!('0' > 5). So basically, if it's undefined, order it like '0' instead of 0.

apenwarr/afterquery,apenwarr/afterquery,apenwarr/afterquery,apenwarr/afterquery,apenwarr/afterquery