Comment Re:Reinventing the wheel (Score 3, Informative) 128
Solr serves a different purpose to SQL. It is optimised for searching using text indexing with fancy ways of matching, weighting results when finding matches. Solr is actually a separate non-SQL database that you keep in sync with your real database. I've found it fits its purpose very well, and you rarely worry about the XML as library support handles it.
SQL is great if you already know exactly what you're looking for. Solr is great if a human is performing a search.