I'm using Sitecore 9.1 and SXA 1.8, I'm using SXA boosting rule of where the field contains Search Box query, this rule doesn't work when the Search Box query is multiple words that are not in order.
For example if I have item that its name is "Drive a car" that I'm applying the boosting rule on it, if I search with "drive a", the boosting rule will work, if I search with "car drive", it won't.
After investigation I found out that Solr doesn't support wildcard searches within single terms.
So I'll have to create a predicate for boosting word by word as the SXA do in its Search Service.
I tried extending the SXA Boosting Service, but I couldn't know where or how add the predicate. Is there is any other solution for this like Solr configuration, or it's not duable.