使 date_trunc() 从星期日开始而不是星期一

Question

Select date_trunc('week',dateTime) Date_week, Max(Ranking) Runing_Total_ID
    from (select datetime, id , dense_rank () over (order by datetime) as Ranking
          from Table1)
 group by 1

此查询对我有用，可以按周为我提供总 ID 的运行总数。但是默认情况下，一周在 Postgres 中从星期一开始。有什么办法可以把星期的开始改为星期天吗？

Answer 1

来回移动时间戳：
在将时间戳提供给date_trunc() 之前添加一天，然后再次减去：

SELECT date_trunc('week', datetime + interval '1 day') - interval '1 day' AS date_week
     , max(ranking) AS runing_total_id
FROM (
   SELECT datetime, dense_rank() OVER (ORDER BY datetime) AS ranking
   FROM   table1
   ) sub
GROUP  BY 1;

见：

• PostgreSQL custom week number - first week containing Feb 1st