如何缩短SQL长UNION ALL查询

StackOverflow https://stackoverflow.com/questions/543442

  •  23-08-2019
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题

我要缩短这个查询，而我在SQL不错，我还在学习。

    SELECT
        'doejoh',
        DATETIME,
        [Recipient-Address], [Message-Subject], [Sender-Address] 
    FROM
        dbo.Logs 
    WHERE
        LEFT([Recipient-Address], 6) IN ('doejoh') 
UNION ALL 
    SELECT
        'doejoh',
        DATETIME,
        [Recipient-Address], [Message-Subject], [Sender-Address] 
    FROM
        dbo.Logs 
    WHERE
        LEFT([Recipient-Address], 10) IN ('john.doe@g') 
UNION ALL 
    SELECT
        'doejoh',
        DATETIME,
        [Recipient-Address], [Message-Subject], [Sender-Address] 
    FROM
        dbo.Logs 
    WHERE
            LEFT([Sender-Address], 6) IN ('doejoh') 
    UNION ALL 
    SELECT
        'doejoh',
        DATETIME,
        [Recipient-Address], [Message-Subject], [Sender-Address] 
    FROM
        dbo.Logs 
    WHERE
            LEFT([Sender-Address], 10) IN ('john.doe@g')
    ORDER BY
        DateTime

我要使用这个联盟，因为在同一个表中，有针对每个用户和他们的电子邮件地址，4种不同的可能性。话虽这么说，我有30个用户，那么30x4将120团在这整个查询。第一列是用户名的原因是因为我使用的水晶报表的列。

我只是希望创造我的查询一些逻辑，这将缩短下来，而在同一时间，每个用户到适当的第一列“分配”。

<强>编辑补充

虽然这将缩短我的查询，我还是得有30个工会：

SELECT
   'doejoh',
   DATETIME,
   [Recipient-Address], [Message-Subject], [Sender-Address] 
FROM
   dbo.Logs 
WHERE
   LEFT([Recipient-Address], 6) IN ('doejoh') OR
   LEFT([Recipient-Address], 10) IN ('john.doe@g') OR
   LEFT([Sender-Address], 6) IN ('doejoh') OR
   LEFT([Sender-Address], 10) IN ('john.doe@g')
ORDER BY
   DateTime

由于下一个用户将被联合到前一个：

UNION ALL 
SELECT
   'doejan',
   DATETIME,
   [Recipient-Address], [Message-Subject], [Sender-Address] 
FROM
   dbo.Logs 
WHERE
   LEFT([Recipient-Address], 6) IN ('doejan') OR
   LEFT([Recipient-Address], 10) IN ('jane.doe@g') OR
   LEFT([Sender-Address], 6) IN ('doejan') OR
   LEFT([Sender-Address], 10) IN ('jan.doe@g')

等等等等......任何短呢？

有帮助吗？

解决方案

是否有这样的一个理由是行不通的？

CREATE TABLE #TempNames
(
    shortname nvarchar(6),
    longname nvarchar(10)
)

INSERT INTO #TempNames (shortname, longname) VALUES('doejoh', 'john.doe@g')
INSERT INTO #TempNames (shortname, longname) VALUES('doejan', 'jan.doe@g')
INSERT INTO #TempNames (shortname, longname) VALUES('smibob', 'bob.smith@g')

SELECT
    #TempName.shortname,
    DATETIME,
    [Recipient-Address], [Message-Subject], [Sender-Address]
FROM
    dbo.Logs
INNER JOIN
    #TempNames
ON
    LEFT([Recipient-Address], 6) = #TempNames.shortname
OR
    LEFT([Recipient-Address], 10) = #TempNames.longname
OR
    LEFT([Sender-Address], 6) = #TempNames.shortname
OR
    LEFT([Sender-Address], 10) = #TempNames.longname

其他提示

您应该重写查询为：

SELECT
   'doejoh',
   DATETIME,
   [Recipient-Address], [Message-Subject], [Sender-Address] 
FROM
   dbo.Logs 
WHERE
   LEFT([Recipient-Address], 6) IN ('doejoh') OR
   LEFT([Recipient-Address], 10) IN ('john.doe@g') OR
   LEFT([Sender-Address], 6) IN ('doejoh') OR
   LEFT([Sender-Address], 10) IN ('john.doe@g')
ORDER BY
   DateTime

应该是相同的选择方面，只是有点更快，更容易理解，我想。

马克

创建的映射表，并加入到它。

例如。类似

select user_name, DateTime .... 
from Logs
join Users on 
   LEFT([Recipient-Address], 6) IN (user_name) OR
   LEFT([Recipient-Address], 10) IN (user_email) OR
   LEFT([Sender-Address], 6) IN (user_name) OR
   LEFT([Sender-Address], 10) IN (user_email)

你能不能只使用... 

SELECT
    'doejoh',
    DATETIME,
    [Recipient-Address], [Message-Subject], [Sender-Address] 
FROM
    dbo.Logs 
 WHERE
    (LEFT([Recipient-Address], 10) IN ('john.doe@g'))
or  (LEFT([Recipient-Address], 6) IN ('doejoh') )
or  ( LEFT([Sender-Address], 10) IN ('john.doe@g'))
or  (LEFT([Sender-Address], 6) IN ('doejoh') )

与30人的电子邮件地址创建一个表。 表：电子邮件 列：short6，long10，电子邮件

然后仅使用1 UNION ALL 

Select Emails.short6, Logs.DateTime, Logs.[Recipient-Address], Logs.[Message-Subject], Logs.[Sender-Address]
From Emails JOIN Log on Emails.email = Log.[Recipient-Address]
Where LEFT([Recipient-Address], 6) = Emails.short6 
or LEFT([Recipient-Address], 10) = Emails.long10

union all

Select Emails.short6, Logs.DateTime, Logs.[Recipient-Address], Logs.[Message-Subject], Logs.[Sender-Address]
From Emails JOIN Log on Emails.email = Log.[Sender-Address]
Where LEFT([Sender-Address], 6) = Emails.short6 
or LEFT([Sender-Address], 10) = Emails.long10
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