How many documents are there with the document type code "CV"?
SELECT count ( T2.Document_Date )  FROM Projects AS T1 JOIN Documents AS T2 ON T1.project_id   =   T2.project_id WHERE T2.Document_Type_Code  =   "CV"
count of documents refers to COUNT(); documents with document type code 'CV' refers to WHERE Document_Type_Code = 'CV';