1.求平均值
select name, avg(balance) over(partition by name) as avg from channel;根据name分组求balance的平均值
2.求总和
select name, sum(balance) over(partition by name) as balanveAvg from channel;根据name求balance的总和
3.根据balance排序，选出拍第一的金额
select name, channel, balance, first_value(balance) over(partition by name) as balanveAvg from channel;
4.求总和
select name, channel, balance, sum(balance) over() as balance from channel;
5.序号窗口函数
根据balance排序，生成对应的序号
select name, channel, balance, row_number() over(order by balance) as sort from channel;row_number
rank
相同的值序号一样，不会跳过自增
dense_rank
相同的值序号一样，会跳过自增
