Php count()使用一对多关系分页,其中
主要问题是关系部分上的“WHERE IN”,它使找到的行相乘。Php count()使用一对多关系分页,其中,php,mysql,join,orm,pagination,Php,Mysql,Join,Orm,Pagination,主要问题是关系部分上的“WHERE IN”,它使找到的行相乘。 例如,为了更好地查看正在发生的事情,我添加了GROUP_CONCAT: SELECT COUNT(*), GROUP_CONCAT(sections.name SEPARATOR '; ') FROM users LEFT JOIN users_sections ON (users.id = users_sections.user_id) LEFT JOIN sections ON (users_sections.section_
例如,为了更好地查看正在发生的事情,我添加了GROUP_CONCAT:
SELECT COUNT(*),
GROUP_CONCAT(sections.name SEPARATOR '; ')
FROM users
LEFT JOIN users_sections ON (users.id = users_sections.user_id)
LEFT JOIN sections ON (users_sections.section_id = sections.id)
GROUP BY users.id
Finds:
'2', 'Registered; admins'
'3', 'Registered; admins; dudes'
'1', 'Registered'
共找到3行,正确,但结果无效。现在添加WHERE IN部分:
SELECT COUNT(*),
GROUP_CONCAT(sections.name SEPARATOR '; ')
FROM users
LEFT JOIN users_sections ON (users.id = users_sections.user_id)
LEFT JOIN sections ON (users_sections.section_id = sections.id)
WHERE sections.id IN (2,3)
GROUP BY users.id
Finds:
'2', 'Registered; admins'
'2', 'Registered; admins'
'1', 'Registered'
即使是正确的,但毫无用处。我需要一个“3”作为计数结果。好吧,那么,让我们把这群人移除,然后…祈祷
SELECT COUNT(*)
FROM users
LEFT JOIN users_sections ON (users.id = users_sections.user_id)
LEFT JOIN sections ON (users_sections.section_id = sections.id)
WHERE sections.id IN (2,3)
GROUP BY users.id
Find:
'2'
'2'
'1'
和以前一样。让我们试试这个:
SELECT COUNT(*) > 0
...
Find:
'1'
'1'
'1'
嘿,看起来不错!让我们尝试一下(希望最终):
真伤心…我怎样才能得到这方面的计数,或者这是不可能的?您想要做的(如果我读得正确的话)是在特定条件适用的情况下计算不同的用户ID。我无法从中找出真正的问题,但我认为你需要它:
SELECT
COUNT( DISTINCT users.id)
FROM
users
LEFT JOIN users_sections ON (users.id = users_sections.user_id)
LEFT JOIN sections ON (users_sections.section_id = sections.id)
WHERE
sections.id IN (2,3)
SELECT
COUNT( DISTINCT users.id)
FROM
users
LEFT JOIN users_sections ON (users.id = users_sections.user_id)
LEFT JOIN sections ON (users_sections.section_id = sections.id)
WHERE
sections.id IN (2,3)