Question

我需要缩短这个查询，虽然我非常擅长SQL，但我还在学习。

    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

我必须使用此联合，因为在同一个表中，每个用户及其电子邮件地址有4种不同的可能性。话虽这么说，我有30个用户，所以在整个查询中30x4将是120个组。第一列必须是用户名的原因是因为我在Crystal Report中使用该列。

我只是想为我的查询创建一些逻辑来缩短它，同时将每个用户“分配”到适当的第一列。

已编辑添加

虽然这会缩短我的查询，但我仍然需要有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

因为下一个用户将与前一个用户联合：

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')

依旧等等......任何更短的方式？

Answer 1

您应该将查询重写为：

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

在选择方面应该是相同的，我认为只是更快，更容易理解。

马克

Answer 2

有这样的事情是行不通的吗？

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

Answer 3

创建一个映射表并加入它。

例如。

之类的东西

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)

Answer 4

你不能只使用......

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') )

Answer 5

创建一个包含30个人的电子邮件地址的表格。表：电子邮件列：short6，long10，电子邮件

然后只使用1个联合

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

如何在SQL中缩短长UNION ALL查询

5 个答案: