On 6/1/2013 10:32 AM, Bala wrote: > Can somebody tell me if i can achieve SQL MINUS query in solr . here is > Sample SQL MINUS query. Need how to get the same in solr > > select field1, field2, ... field_n > from tables > MINUS > select field1, field2, ... field_n > from tables;
I had to look up what this meant. New versions of Solr do have some *limited* join capability that also works between cores. It looks like currently it only works for matching, not excluding: http://wiki.apache.org/solr/Join http://stackoverflow.com/questions/12665797/is-solr-4-0-capable-of-using-join-for-multiple-core It's currently not possible to do mass comparisons between separate Solr indexes in any way that would give you MINUS. You could probably write the capability in client code, but it would not be efficient. Solr is not designed to replace relational databases, and in fact works best with a completely flattened schema. Relational database software is designed to do a lot of things very efficiently that are difficult or impossible in a search-oriented system. If you come up with a way to modify Solr to add this capability, patches are always welcome. Thanks, Shawn
