Search across Solr Cores

Solr Findings: Multi-Core, Multi-item search in Solr
Below listed some features which will be helpful while working with Solr.

1) Searching across all cores: There are some cases where we need to search across the multi-cores environment in Solr. Using shards, we can enable this feature.
Solr's feature 'shards' split huge indexes to make the search faster. Cores can be treated as shards for an 'All core search'. Some of the samples are given below Say we have two cores (us_en,es_en).
Both cores can be queried using the below parameters
http://localhost:8983/solr/us_en/select?shards=localhost:8983/solr/us_en,localhost:8983/solr/es_en&indent=true&q=*:*&df=title

Here df is the default query field and we are doing a '*' search.

2) For multi-item search: Let us say we need to search multiple items using the same query. We can do a multi-parameter search to a core as shown below.

http://localhost:8983/solr/es_en/select?q=*:*&df=id&wt=json&indent=true& fq= (id:”id1” | id: “id2” | id: “id3”)

Tested URL as shown.
http://localhost:8983/solr/us_en/select?q=*%3A*&df=id&wt=json&indent=true&fq=(id:"id1" | id:"id2" | id:"id3")