获取Postgres表中列的最常见日期

Question

我希望看到小部件在我的Postgres数据库中获得created_at的最常见的一周。

这是我所拥有的，但它返回平均值（3.744 ...），而不是表示一周中最常见日的整数。有谁知道我怎么能改善这个？

SELECT AVG(start_day) AS start_day
FROM (SELECT date_part('dow', created_at) AS start_day
      FROM widgets) TMP;

Answer 1

SELECT date_part('dow', created_at) AS start_day
  FROM widgets
 GROUP BY date_part('dow', created_at)
 ORDER BY COUNT(*) DESC
 LIMIT 1

Answer 2

SELECT start_day, count(*)
FROM (
  SELECT date_part('dow', created_at) AS start_day
  FROM widgets) sub
GROUP BY 1
ORDER BY 2 DESC
LIMIT 1;