函数说明：
grouping sets
在一个 group by 查询中，根据不同的维度组合进行聚合，等价于将不同维度的 group by 结果集进行 union all
cube
根据 group by 的维度的所有组合进行聚合
rollup
是 cube 的子集，以最左侧的维度为主，从该维度进行层级聚合。
-- grouping sets select order_id, departure_date, count(*) as cnt from ord_test where order_id=410341346 group by order_id, departure_date grouping sets (order_id,(order_id,departure_date)) ; ---- 等价于以下 group by order_id union all group by order_id,departure_date -- cube select order_id, departure_date, count(*) as cnt from ord_test where order_id=410341346 group by order_id, departure_date with cube ; ---- 等价于以下 select count(*) as cnt from ord_test where order_id=410341346 union all group by order_id union all group by departure_date union all group by order_id,departure_date -- rollup select order_id, departure_date, count(*) as cnt from ord_test where order_id=410341346 group by order_id, departure_date with rollup ; ---- 等价于以下 select count(*) as cnt from ord_test where order_id=410341346 union all group by order_id union all group by order_id,departure_date
结果：grouping_sets, cube, rollup
