mysql - 查询以获取一天中基于小时的最多 View

Question

我有表“访客”这些字段是

    id = integer
    ip = char
    route = char
    created_at = timestamp

我想按小时计算分组，我使用了查询

    SELECT * , HOUR(created_at) AS created_hour , COUNT(created_hour)
 FROM `visitors` WHERE created_at > DATE(NOW()) GROUP BY created_hour

但我得到这个错误，我可以根据“分组依据”“计数”

SQL query: Documentation

SELECT * , HOUR(created_at) AS created_hour , COUNT(created_hour) FROM `visitors` WHERE created_at > DATE(NOW()) GROUP BY created_hour LIMIT 0, 25

MySQL said: Documentation
#1054 - Unknown column 'created_hour' in 'field list'

Answer 1

将 COUNT(created_hour) 更改为 COUNT(*)。

不要使用WHERE created_at > DATE(NOW())，而是使用WHERE created_at < DATE(NOW())。您查询中的当前 WHERE 条件将强制不返回任何内容。