CREATE TABLE Documents_with_Expenses (document_id VARCHAR(255), budget_type_code VARCHAR(255)); CREATE TABLE Documents (document_date VARCHAR(255), document_id VARCHAR(255))
What are the dates for the documents with both 'GV' type and 'SF' type expenses?
    
SQL: SELECT T1.document_date FROM Documents AS T1 JOIN Documents_with_Expenses AS T2 ON T1.document_id = T2.document_id WHERE T2.budget_type_code = 'GV' INTERSECT SELECT T1.document_date FROM Documents AS T1 JOIN Documents_with_Expenses AS T2 ON T1.document_id = T2.document_id WHERE T2.budget_type_code = 'SF'