解釋:按t_time分組(示例將t_time分為2005,2006二個組), cl排序(默認:升序)。降序可設置ORDER BY cl desc
函數ROW_NUMBER() OVER () ,RANK() OVER ()RANK(),DENSE_RANK() OVER ()的區別在這就不詳細介紹了,可參考:開窗函數-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…有興趣的朋友可以試試,這里就不詳解了!