SQL使用SUBSTRING和CHARINDEX减去字符串

Question

我有以下字符串：

'{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com'

而且我只想提取MessageID部分：

<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>

我尝试使用子字符串和charindex函数失败：

   SELECT SUBSTRING('{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com',
   (SELECT CHARINDEX(' Message-ID=<','{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com')),
   (SELECT CHARINDEX('>, Authentication-Results', '{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com')))

和我查询的结果是：

 Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com

我做错了什么？

Answer 1

SUBSTRING的第三个参数是长度。 您的陈述正在传递角色位置...

SUBSTRING ( expression ,start , length )

尝试这个：

SELECT SUBSTRING('{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com',
(SELECT CHARINDEX(' Message-ID=<','{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com')),
CHARINDEX('>, Authentication-Results', '{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com')
-
CHARINDEX(' Message-ID=<','{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com') 
+1)

（在您的示例中，该值应为75）

Answer 2

它是Charindex函数。 请参考http://msdn.microsoft.com/en-us/library/ms186323.aspx 。 Charindex获取字符的第一个出现索引，因此

   select CHARINDEX('A','TESTING A LETTER')

上面的代码将返回9，如果您执行子字符串操作，则该子字符串将从9开始，而不是从字符串末尾开始。

对于您的查询，解决方案如下；

  DECLARE @String varchar(500) = '{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com'

  SELECT SUBSTRING(@String,
   CHARINDEX('Message-ID=<',@String) + 12,
   CHARINDEX('>',@String,CHARINDEX('Message-ID=<',@String)))

Answer 3

尝试以下操作：添加替换：

SELECT REPLACE(SUBSTRING('{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification- 
Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-a32410de78@abd.local.test.global>, 
Authentication-Results=vadmzmail2342.test.com', (SELECT CHARINDEX(' Message-ID=<','{Mapi-Reply-
Recipient-Smtp-Proxies=, Mapi-Non-Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-
4345c-b232429-a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com')),
(SELECT CHARINDEX('>, Authentication-Results', '{Mapi-Reply-Recipient-Smtp-Proxies=, Mapi-Non-
Receipt-Notification-Requested=true, Message-ID=<6a2k4081-f6134-4345c-b232429-
a32410de78@abd.local.test.global>, Authentication-Results=vadmzmail2342.test.com'))) ,' Message-ID=  
<','')