Postgres SQL选择上一个有效日期

我在研究博士后，遇到了一个有趣的问题，我还没有解决它

假设一家公司每隔几天发货一次。这是装运表，用于记录其装运的集装箱数量：

分支字符；日期；容器整数 我想要这份报告：

分支字符；日期；容器整数；前一天；上一个日期的集装箱；希腊字母表的第4个字母 我用这个：

Select a.*, b.*, (a.containers – b.containers) delta
From shipping a
Join shipping b 
ON 
b.date=(select date from shipping where date<a.date order by date desc limit 1)

当桌子很小的时候，这就行了。如果表增长到100000条记录，则此查询速度较慢。我想知道你们有没有更有效的方法

谢谢， 斯蒂芬

只需使用滞后功能

Select s.Branch, s.Date, s.containers,
       lag(s.Date) over (partition by branch order by date) as prev_Date,
       lag(s.containers) over (partition by branch order by date) as prev_Containers
from shipping s;

Select a.*, b.*, (a.containers – b.containers) delta
From shipping a
Join shipping b 
ON 
b.date=(select date from shipping where date<a.date order by date desc limit 1)

Select s.Branch, s.Date, s.containers,
       lag(s.Date) over (partition by branch order by date) as prev_Date,
       lag(s.containers) over (partition by branch order by date) as prev_Containers
from shipping s;