[Koha] Looking to Query Indicators

Hi all, Anyone know if there is a way to query a marc field based on the indicator value. I have this report (which works): select b.title, b.author, ExtractValue(m.marcxml,'//datafield[@tag="521"]/subfield[@code>="a"]') AS lexile from biblio b left join biblioitems m using (biblionumber) where ExtractValue(m.marcxml,'//datafield[@tag="521"]/subfield[@code>="a"]') between <<Lexile between>> and <<and>> But I want to only query 521s that have a 8# in the indicators. My report will find all of the below: 521 2# - TARGET AUDIENCE NOTE Target audience note 4-8. 521 0# - TARGET AUDIENCE NOTE Target audience note 8.8. 521 8# - TARGET AUDIENCE NOTE Target audience note 1150 But I only want the last one. Nicole