CREATE TABLE Documents (Document_ID INT, Document_Type_Code CHAR, Project_ID INT, Document_Date DATETIME, Document_Name VARCHAR, Document_Description VARCHAR, Other_Details VARCHAR)
CREATE TABLE Ref_Budget_Codes (Budget_Type_Code CHAR, Budget_Type_Description VARCHAR)
CREATE TABLE Documents_with_Expenses (Document_ID INT, Budget_Type_Code CHAR, Document_Details VARCHAR)
CREATE TABLE Ref_Document_Types (Document_Type_Code CHAR, Document_Type_Name VARCHAR, Document_Type_Description VARCHAR)
CREATE TABLE Accounts (Account_ID INT, Statement_ID INT, Account_Details VARCHAR)
CREATE TABLE Projects (Project_ID INT, Project_Details VARCHAR)
CREATE TABLE Statements (Statement_ID INT, Statement_Details VARCHAR)

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 "BK" = "Document_Type_Code" GROUP BY "Project_ID"