[英]Using MAX shuffles records around
我有以下影响表:
我需要获得利益相关者的最新影响力...
我有以下查询,但由于MAX没有返回完整的记录,所以它混淆了行数据:
SELECT stakeholder_id, MAX(created_at) AS maxca, influence
FROM influences
WHERE
project_id = 1 AND
deleted_at IS NULL
GROUP BY stakeholder_id
您可以看到,对那个maxca和interestholder_id的影响应该是3,而不是5。
我该如何克服这个问题? 我现有的全部陈述是这样的:
SELECT `stakeholders`.*, `influences`.`influence`
FROM `project_stakeholder`
INNER JOIN `stakeholders` ON `project_stakeholder`.`stakeholder_id` = `stakeholders`.`id`
INNER JOIN `stakeholder_profiles` ON `stakeholder_profiles`.`stakeholder_id` = `stakeholders`.`id`
LEFT JOIN `stakeholder_profile_tag` ON `stakeholder_profile_tag`.`stakeholder_profile_id` = `stakeholder_profiles`.`id`
LEFT JOIN `stakeholder_profile_group` ON `stakeholder_profile_group`.`stakeholder_profile_id` = `stakeholder_profiles`.`id`
LEFT JOIN `influences` ON `influences`.`stakeholder_id` = `stakeholders`.`id`
INNER JOIN `projects` ON `project_stakeholder`.`project_id` = `projects`.`id`
LEFT JOIN (
/*! This is the bit that doesn't work */
SELECT stakeholder_id, MAX(created_at) AS maxca
FROM influences
WHERE
project_id = 1 AND
deleted_at IS NULL
GROUP BY stakeholder_id
)
iu ON `iu`.`stakeholder_id` = influences.stakeholder_id AND
iu.maxca = influences.created_at
WHERE `projects`.`id` = '1'
GROUP BY `stakeholders`.`id`
这似乎可行:
SELECT `stakeholders`.*, iu.influence
FROM `project_stakeholder`
INNER JOIN `stakeholders` ON `project_stakeholder`.`stakeholder_id` = `stakeholders`.`id`
INNER JOIN `stakeholder_profiles` ON `stakeholder_profiles`.`stakeholder_id` = `stakeholders`.`id`
LEFT JOIN `stakeholder_profile_tag` ON `stakeholder_profile_tag`.`stakeholder_profile_id` = `stakeholder_profiles`.`id`
LEFT JOIN `stakeholder_profile_group` ON `stakeholder_profile_group`.`stakeholder_profile_id` = `stakeholder_profiles`.`id`
INNER JOIN `projects` ON `project_stakeholder`.`project_id` = `projects`.`id`
LEFT JOIN (
select i1.*
from influences i1
join
(
SELECT stakeholder_id, MAX(created_at) AS maxca
FROM influences
WHERE project_id = 1
AND deleted_at IS NULL
GROUP BY stakeholder_id
) i2 on i1.stakeholder_id = i2.stakeholder_id
and i1.created_at = i2.maxca
) iu ON `iu`.`stakeholder_id` = stakeholders.id
WHERE `projects`.`id` = '1'
GROUP BY `stakeholders`.`id`
select i1.*
from influences i1
join
(
SELECT stakeholder_id, MAX(created_at) AS maxca
FROM influences
WHERE project_id = 1
AND deleted_at IS NULL
GROUP BY stakeholder_id
) i2 on i1.stakeholder_id = i2.stakeholder_id
and i1.created_at = i2.maxca
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