获取复杂查询的计数结果

Question

让我们假设我有这个SQL查询

SELECT max(times_viewed) as m, member_id, (select count(viewed_url) from exp_member_page_tracker  where member_id=mpv.member_id)
FROM `exp_member_page_tracker` mpv
group by member_id

我需要计算所有结果。我是这样做的

SELECT count(member_id) from ( SELECT max(times_viewed) as m, member_id, (select count(viewed_url) from exp_member_page_tracker where member_id=mpv.member_id)
FROM `exp_member_page_tracker` mpv
group by member_id) as m2

但我不确定这是多么有效。能否请您建议我如何以最佳方式计算结果？

由于

Answer 1

对于你的子查询，我是否遗漏了一些东西，这是不是同样的结果更有效率？ 尝试在sqlfiddle：

http://sqlfiddle.com/#!2/a03cf/9

<强>此致：

SELECT member_id, max(times_viewed) as max_times_viewed 
, (select count(viewed_url) from exp_member_page_tracker  where member_id=mpv.member_id) as countOfViewedUrl
FROM `exp_member_page_tracker` mpv
group by member_id;

替代方案：

SELECT member_id, max(times_viewed) as max_times_viewed
, count(viewed_url) as countOfViewedUrl
FROM `exp_member_page_tracker` mpv
group by member_id;