0. 说明
1. 窗口函数(开窗函数) over
1.1 说明
1 preceding //前一个
1 following //后一个
current row //当前行
unbounded preceding //无上限
unbounded following //无下限
1.2 测试
# 以行定义窗口界限 select id, name, age , sum(age)over(order by id rows between current row and 2 following) from user_par; # 以值定义窗口界限 select id, name, age , sum(age)over(order by age range between current row and 10 following) from user_par;