variable for determining which selection has 2nd most volume backing

Hi, is there a variable to select the horse who has the 2nd most volume backing?
Thanks in advance

Hi
By "back volume" you are meaning unmatched back bets which are on the lay side best 3 lay prices?

selections sorting order is defined by lay_volume
and selections trigger expression match_index is equal to matching_number -1 

Sorry Mark, I have forgotten a few details.
I want to pick the horse AT the off who has received the 2nd most backing in terms of volume.
It might not necessarily be the 2nd favourite.

also I meant matched back bets.

Hi
selections sorting order is defined by volume
and selections trigger expression match_index is equal to matching_number -1
  

so matching_number equal to -1 is the 2nd most backed. Out of interest, what would most backed be? 0? and would 3rd most backed be -2?

Hi
sorting order is defined by volume sorts selections by matched volume in ascending order, lowest first highest last
match_index is the index of matching selections in the sorted list above
matching_number is the total number of selections that match previous conditions

so match_index of first in the list (lowest volume in this example) is 1
second highest traded volume is second last selection in the list as sorted above (matching_number -1)
yes third most traded match_index = matching_number -2