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我在做什么：

我正在编写一个 C# 应用程序，它将帮助员工处理电子邮件。我有一个包含邮件的数据库（MS SQL Server 2008 Express）。一个表包含邮件本身（每一行都有 msgId、发件人、收件人、主题、正文等列），另一个表包含员工如何处理邮件的数据 - 每当电子邮件分配了某些属性时，都会有一个新行与属性保存到第二个表。第二个表包含列：msgId、forTeam、notForTeam、processedByTeam。每当员工将消息标记为与其团队相关时，都会在 forTeam 列中保存一行带有 TEAMXX 值的行。每当员工对电子邮件执行其他操作时，都会将具有 TEAMXX 值的行保存在 processesByTeam 列中。

我正在尝试获取具有以下值的电子邮件：
forTeam：'TEAM01'
notForTeam：与'TEAM01'不同的
所有内容 processesByTeam：与'TEAM01'不同的所有内容

我使用 MailAssignments 表在 Mails 表上执行 LEFT JOIN，然后在 WHERE 之后放置上述条件。结果应该显示已分配给 TEAM01 但尚未由该团队的员工处理的消息。



问题：

我无法让 SQL 查询正常工作。条件的任何组合都将返回额外的行（例如，当我想省略这些时，使用属性 notForTeam='TEAM01'！）或给我一个错误，即日期时间由于某种原因格式不正确（我正在按接收时间对电子邮件进行排序）。

示例查询：

SELECT TOP 30 Mails.* 
FROM Mails 
LEFT JOIN MailAssignments 
ON Mails.msgId = MailAssignments.msgId 
WHERE
(MailAssignments.forTeam='TEAM01') 
AND (MailAssignments.notForTeam<>'TEAM01' OR MailAssignments.notForTeam IS NULL) 
AND (MailAssignments.processedByTeam<>'TEAM01' OR MailAssignments.processedByTeam IS NULL)
ORDER BY Mails.sortingTime DESC

即使我将 WHERE 之后（以及 ORDER BY 之前）的条件减少到(MailAssignments.notForTeam<>'TEAM01')进行测试，由于某种原因，我仍然会收到错误消息。

我错过了什么或做错了什么？



更新：

似乎这(MailAssignments.notForTeam<>'TEAM01')以某种方式导致了问题。其他一切正常（等号也可以：MailAssignments.notForTeam='TEAM01'）但是当我添加notForTeam<>条件时，我得到不正确的日期时间错误（WTF？：/）

System.Data.SqlTypes.SqlTypeException：SqlDateTime 溢出。必须介于 1753 年 1 月 1 日上午 12:00:00 和 9999 年 12 月 31 日晚上 11:59:59 之间。



更新 - 示例：

table with mails ("Mails"):
msgId sender  subject body  received (sortingTime)
53    x@x.com test    test  2012-05-11 11:00
54    b@b.com test2   test2 2012-05-10 10:00
55    h@h.com blah    blah  2012-05-11 12:00
56    t@t.com dfgg    dfgg  2012-05-11 12:30


table with assignments ("MailAssignments"):
msgId forTeam notForTeam  processedByTeam
54    null    TEAM02      null            - this means TEAM02 hid the mail from their view
54    TEAM01  null        null            - this means TEAM01 assigned the mail to them
54    null    null        TEAM01          - TEAM01 has processed the mail

53    TEAM01  null        null            - invisible to other teams
53    null    TEAM01      null            - invisible for TEAM01 (and also for others because of the above)

56    TEAM01  null        null
56    null    null        TEAM01          - mail processed by TEAM01

55    TEAM02  null        null            - assigned to TEAM02 but not processed yet


Now, I want my C# app to have a view which will display mails as "This Team's", ie.:
1. mail 54 was first hidden for TEAM02 - should be invisible for them
2. mail 54 was assigned to TEAM01 - should be now visible for them in "This Team's" view
3. mail 54 was processed by TEAM01 - should be now invisible in "This Team's" view

4. mail 53 was assigned to TEAM01 - should visible in their "This Team's" view (and ONLY for them)
5. mail 53 was hidden for TEAM01 - should be invisible to TEAM01 (and for anyone else because of prev. action)

6. mail 56 was assigned to TEAM01 - should be now visible only to TEAM01 in "This Team's"
7. mail 56 was processed by TEAM01 - should be now invisible for TEAM01 in "This Team's"

So, with the present data in both tables, finally, TEAM02 for example should see in their "This Team's" view only:
mail 55
4

2 回答 2

2 
Select TOP 30 *
From Mails As M
Where Exists    (
                Select 1
                From MailAssignments As MA1
                Where MA1.msgid = M.msgid
                    And MA1.forTeam = 'TEAM01'
                Except
                Select 1
                From MailAssignments As MA1
                Where MA1.msgid = M.msgid
                    And ( MA1.processedByTeam = 'TEAM01' 
                         Or MA1.notForTeam = 'TEAM01' )
                )
Order By M.received Desc

SQL 小提琴版本。

拥有示例数据和模式会使世界变得与众不同。MailAssignments错过的是每行有多行Mails。因此，当您说要排除 where 行时notForTeam = 'TEAM01'，真正的意思是排除任何具有该值的关联 msgid。我已经更新了我的查询以适应该请求。您可能怀疑的Except子句消除了第二个查询中存在于第一个查询中的任何匹配值。由于我在两个查询中都使用了常量，如果第二个查询返回给定 msgid 的任何行，它将使整个 Exists 查询不返回任何行并排除 msg。

也就是说，我们没有得到任何行，TEAM01因为：

MsgId = 54 is excluded because according to Rule #3, messages 
    that were processed by the team should be excluded.
MsgId = 53 is excluded because notForTeam = 'TEAM01' (Rule #5)
MsgId = 56 is excluded because processedBy = 'TEAM01' (Rule #7)
MsgId = 55 is excluded because forTeam = 'TEAM02'
于 2012-05-12T16:28:45.523 回答
0

尝试：

WHERE
MailAssignments.forTeam='TEAM01'
AND MailAssignments.notForTeam<>'TEAM01'
AND MailAssignments.processedByTeam<>'TEAM01'
ORDER BY Mails.sortingTime DESC

这应该可以解决问题

于 2012-05-12T16:24:00.947 回答