解释:按t_time分组(示例将t_time分为2005,2006二个组), cl排序(默认:升序)。降序可设置ORDER BY cl desc
函数ROW_NUMBER() OVER () ,RANK() OVER ()RANK(),DENSE_RANK() OVER ()的区别在这就不详细介绍了,可参考:开窗函数-排名
row_number() over(partition by … order by …)
rank() over(partition by … order by …)
dense_rank() over(partition by … order by …)
count() over(partition by … order by …)
max() over(partition by … order by …)
min() over(partition by … order by …)
sum() over(partition by … order by …)
avg() over(partition by … order by …)
first_value() over(partition by … order by …)
last_value() over(partition by … order by …)
lag() over(partition by … order by …)
lead() over(partition by … order by …)
等等…有兴趣的朋友可以试试,这里就不详解了!
