Question

我有两张桌子：

projects_tasks
projects_tasks_deadlines

现在我有一个简单的查询，我在截止日期前对每个任务进行排序。起初任务只能有1个截止日期。

然后我被要求能够在一个任务上设置多个截止日期。这就是为什么我有第二张表projects_tasks_deadlines的原因。

我设法允许用户选择应激活哪个截止日期（任务明细）。但是在包含所有任务的列表中，我不知道如何在两个表之间进行排序，如果这至少是可能的。

这是我目前正在使用的查询：

SELECT 
    projects_tasks.id AS task_id,
    projects_tasks.name AS task_name,
    projects_tasks.deadline AS task_deadline,
    projects_tasks.created_by AS task_creator,
    labels.name AS task_label,
    users.name AS task_responsible_name,
    users.surname AS task_responsible_surname,
    users2.name AS task_assigner_name,
    users2.surname AS task_assigner_surname
FROM `projects_tasks`
    INNER JOIN `labels` ON labels.id = projects_tasks.label_id
    INNER JOIN `users` ON users.id = projects_tasks.responsible_id
    INNER JOIN `users` AS `users2` ON users2.id = projects_tasks.created_by
WHERE projects_tasks.project_id = :project_id
AND labels.id != '8'
ORDER BY -projects_tasks.deadline DESC

我如何实现我的目标，检查第二个表中的截止日期是否有效，并使用相应的`task_id。如果找到匹配，请将该截止日期计入计数并排序..

一个例子：

表projects_tasks：

id | name | deadline
--------------------
1  | test | 2016-01-19
2  | test2| 2016-02-15
3  | test | 2016-01-25

表projects_tasks_deadlines

id | task_id | deadline  | active
--------------------------------
1  | 1       | 2016-01-20| 1 // yes
2  | 1       | 2016-01-24| 0 // no
3  | 2       | 2016-02-25| 0

结果应为

2016-01-20 - ＆gt; projects_tasks_deadlines
2016-01-25 - ＆gt; projects_tasks
2016-02-15 - ＆gt; projects_tasks

感谢您的帮助，希望这很清楚......

**更新**

SELECT 
    projects_tasks.id AS task_id,
    projects_tasks.name AS task_name,
    projects_tasks.created_by AS task_creator,
    projects_tasks_deadlines.id AS deadline_id,
    labels.name AS task_label,
    users.name AS task_responsible_name,
    users.surname AS task_responsible_surname,
    users2.name AS task_assigner_name,
    users2.surname AS task_assigner_surname,
    CASE WHEN projects_tasks_deadlines.deadline_active = '1' THEN projects_tasks_deadlines.deadline AS task_deadline ELSE
    projects_tasks.deadline AS task_deadline END
FROM `projects_tasks`
    INNER JOIN `labels` ON labels.id = projects_tasks.label_id
    INNER JOIN `users` ON users.id = projects_tasks.responsible_id
    INNER JOIN `users` AS `users2` ON users2.id = projects_tasks.created_by
    LEFT JOIN projects_tasks_deadlines ON projects_tasks_deadlines.task_id = projects_tasks.id
WHERE projects_tasks.project_id = '1'
AND labels.id != '8'
ORDER BY CASE WHEN projects_tasks_deadlines.deadline_active = 1 THEN -projects_tasks_deadlines.deadline ELSE -projects_tasks.deadline END DESC

我应该如何处理CASE中的SELECT？

Answer 1

您可以通过执行条件订单。如果active = 1，则使用projects_tasks_deadline表中的截止日期，否则使用projects_tasks表。所以像这样：

SELECT 
    projects_tasks.id AS task_id,
    projects_tasks.name AS task_name,
    projects_tasks.deadline AS task_deadline,
    projects_tasks.created_by AS task_creator,
    labels.name AS task_label,
    users.name AS task_responsible_name,
    users.surname AS task_responsible_surname,
    users2.name AS task_assigner_name,
    users2.surname AS task_assigner_surname
FROM `projects_tasks` 
    INNER JOIN `labels` ON labels.id = projects_tasks.label_id
    INNER JOIN `users` ON users.id = projects_tasks.responsible_id
    INNER JOIN `users` AS `users2` ON users2.id = projects_tasks.created_by
LEFT JOIN projects_tasks_deadline ptd ON id = task_id
WHERE projects_tasks.project_id = :project_id
AND labels.id != '8'
ORDER BY CASE WHEN ptd.active = 1 THEN ptd.deadline ELSE projects_tasks.deadline END DESC

希望有道理吗？

Answer 2

我最终找到了解决方案：

CASE

我错过了SELECT中的另一个(CASE WHEN projects_tasks_deadlines.deadline_active = '1' THEN projects_tasks_deadlines.deadline ELSE projects_tasks.deadline END) AS task_deadline：

`<preference name="SplashScreen" value="screen" />
<preference name="SplashScreenDelay" value="10000" />

<platform name="android">
    <splash src="res/screens/android/320X470.jpg" density="land-hdpi" />
    <splash src="res/screens/android/320X470.jpg" density="land-ldpi" />
    <splash src="res/screens/android/320X470.jpg" density="land-mdpi" />
    <splash src="res/screens/android/320X470.jpg" density="land-xhdpi" />
    <splash src="res/screens/android/320X470.jpg" density="port-hdpi" />
    <splash src="res/screens/android/320X470.jpg" density="port-ldpi" />
    <splash src="res/screens/android/320X470.jpg" density="port-mdpi" />
    <splash src="res/screens/android/320X470.jpg" density="port-xhdpi" />
  </platform>

 <vs:plugin name="cordova-plugin-splashscreen" version="3.0.0" />`

这过滤了正确的截止日期，他们也在正确的截止日期前排序。

2个表上的sql排序相同的列名

2 个答案: