Update README.md

README.md

@@ -38,4 +38,5 @@ Below is a description of the dataset fields and additional information about th
 - **sol_sql**: The ground truth SQL solution.  
 - **preprocess_sql**: SQL queries to run before executing the solution or prediction.  
 - **clean_up_sql**: SQL queries to run after the test cases to revert any changes made to the database.  
-- **test_cases**: A set of test cases to validate the predicted corrected SQL.
+- **test_cases**: A set of test cases to validate the predicted corrected SQL.
+- **efficiency**: True if this question need optimization, measure the cost by Query Execution Plan (QEP)