Hooking up Lucene's flexible query parser to evaluate intervals
Naturally it requires Lucene 9.1, we only have Solr 9.1 with Lucene 9.3 that's a minimum requirement.
Declare it in solrconfig.xml as described in guide
<queryParser name="flex" class="org.apache.solr.flexibleqp.FlexibleQP"/>
This jar should be deployed as a Solr Plugin into some lib folder along aside with lucne-queryparser:9.3 or above. Take it here https://repo1.maven.org/maven2/org/apache/lucene/lucene-queryparser/9.3.0/lucene-queryparser-9.3.0.jar
Example iterval query
q={!flex}unstemmed_text:fn:maxgaps(4 fn:unordered(charge account))
Find more interval syntax examples in
see also