query: SELECT max(years_working) ,  min(years_working) ,  avg(years_working) FROM school_bus
question: What-all is the maximum, minimum and average years spend working on a school bus?
query_toks: SELECT max ( years_working ) , min ( years_working ) , avg ( years_working ) FROM school_bus
query_toks_no_value: select max ( years_working ) , min ( years_working ) , avg ( years_working ) from school_bus
question_toks: What-all is the maximum, minimum and average years spend working on a school bus?