I am new to BIRST I need any document or any links for BQL queries.
Do you have any examples of queries you are trying to write?
You can start here:
https://app2103.bws.birst.com/Help/Full/classicbirst/modeling/bqlandexpressions/introduction_to_bql.htm?Highlight=BQL
If you have access to Infor Campus, it is also a good resource. https://campus.infor.com/Saba/Web_spf/NA3P1PRD0027/app/me/pages/pagedetail?id=spage000000000003820