Task: Text to Code
Input (English): Step 1: find the Document_Date of Documents table for which Documents's Document_Type_Code equals GV.
Step 2: For each row in Ref_Document_Types table, find the corresponding rows in Documents table.
Step 3: find Document_Date of the results of step 2 whose Document_Type_Name equals SF.
Step 4: show the rows that are in both the results of step 1 and the results of step 3
Output (English): SELECT T1.Document_Date FROM Documents AS T1 WHERE T1.Document_Type_Code = "GV" INTERSECT SELECT T1.Document_Date FROM Ref_Document_Types AS T2 JOIN Documents AS T1 ON T2.Document_Type_Code = T1.Document_Type_Code WHERE T2.Document_Type_Name = "SF"