1、求截止到当前行不为空最后一个值
select calendar_day,
if_trade_dt,
mkt_code,
last_value(tmp_trade_dt, true) over(partition by mkt_code order by calendar_day desc) as gt_trade_dt,
last_value(tmp_trade_dt, true) over(partition by mkt_code order by calendar_day) as lt_trade_dt
from(
select calendar_day, mkt_code,if_trade_dt, null as tmp_trade_dt from tmp_03
union all
select calendar_day, mkt_code,if_trade_dt, calendar_day as tmp_trade_dt
from tmp_05 ) t1
2、求上一个值和下一个值
select
calendar_day,
if_trade_dt,
mkt_code,
lead(calendar_day, 1, date '2999-12-31') over (partition by mkt_code order by calendar_day) as gt_trade_dt,
lag(calendar_day, 1, date '1900-01-01') over (partition by mkt_code order by calendar_day) as lt_trade_dt
from tmp_06 where if_trade_dt = '是'
3、row_number:按顺序排序，排序的值不会重复，rank:大小一样，排序的值一样，但会占用排名的位置，dense：排序值重复，排名并列，排名依次增加，代码和运行效果如图：
select calendar_dt,
rank() over(order by calendar_dt) rank_rn,
dense_rank() over(order by calendar_dt) dense_rn,
row_number() over(order by calendar_dt) row_rn
from t00_tradedate_extend
where calendar_dt between '20080101' and '20080105'
