SELECT count(*) ,  project_id FROM Documents WHERE document_type_code  =  "BK" GROUP BY project_id
How many documents are with document type code BK for each product id?
SELECT count ( * ) , project_id FROM Documents WHERE document_type_code = `` BK '' GROUP BY project_id
select count ( * ) , project_id from documents where document_type_code = value group by project_id
How many documents are with document type code BK for each product id ?