Question

我是否可以更改此查询，以便像COUNT(WHERE type_id = 2) AS success, COUNT(WHERE type_id = 1) AS error一样阻止使用子查询？

SELECT
                (SELECT COUNT(id) FROM log AS success_log WHERE type_id = 2 AND site_id = site.id AND DAYOFYEAR(success_log.created)) AS success,
                (SELECT COUNT(id) FROM log AS success_log WHERE type_id = 1 AND site_id = site.id AND DAYOFYEAR(success_log.created)) AS error,
                (SELECT COUNT(id) FROM log AS success_log WHERE site_id = site.id AND DAYOFYEAR(success_log.created)) AS total,
                DATE_FORMAT(log.created, "%m-%d-%y") AS `day`
            FROM log
            WHERE site_id = ?
            GROUP BY DAYOFYEAR(created)`

Answer 1

您可以对GroupBy TypeId使用单计数，并将它们插入临时表中，然后选择您想要的方式。

Answer 2

因为他们都是从同一站点的日志表中查询，所以你可以直接运行表ONCE并在一个总和中应用和IMMEDIATE IF（）测试....如果记录属于给定类型， count为1，否则为0 ...获取类型1或类型2的总和，简单计数（*）获取相关日期的总计数。

SELECT
      DATE_FORMAT(log.created, "%m-%d-%y") AS `day`,
      sum( if( type_id = 2, 1, 0 )) as NumberSuccess,
      sum( if( type_id = 1, 1, 0 )) as NumberError,
      count(*) as TotalRecords
   from
      log
   where
      site_id = ?
   group by
      DAYOFYEAR(created)

MySQL优化 - 防止子查询

2 个答案: