在 SQL 中使用正则表达式提取位于特殊字符之间的电子邮件

Question

如何在 SQL 中使用正则表达式从这种特定的字符串模式中仅提取电子邮件？

我有: tb_1

Logmessage
Alan Robert <alan.robert@gmail.com> was assigned to <richard@yahoo.com> and <nelson@gmail.com>
Alan Robert <alan.robert@gmail.com> was unassigned to <khanjoyty@gmail.com> and <katy@gmail.com>

我想要的： tb_2

email_1	email_2	email_3
alan.robert@gmail.com	richard@yahoo.com	nelson@gmail.com
alan.robert@gmail.com	khanjoyty@gmail.com	katy@gmail.com

我已经有了一个解决方案，但是 tb_1 table 有大量的行，所以我的查询输出需要太多时间。这就是为什么我认为 regex 可能更节省时间。

我的查询：

with cte as(
Select replace(replace(replace(replace(right(@logmessage, len(logmessage)-charindex('<', logmessage)+1), 
                                         Case when logmessage like '%unassigned%' Then ' was unassigned to ' 
                                       When logmessage like '%assigned%' then ' was assigned to ' End , '.'),' and ', '.'), 
                                                                        '<', '['  ),'>', ']') logmessage
From tb_1)

Select 
       PARSENAME(logmessage, 3) AS email_3,
       PARSENAME(logmessage, 3) AS email_2,
       PARSENAME(logmessage, 1) AS email_1
From cte

Answer 1

使用辅助函数

示例或dbFiddle

Declare @YourTable Table (LogID int,[Logmessage] varchar(500))  Insert Into @YourTable Values 
 (1,'Alan Robert <alan.robert@gmail.com> was assigned to <richard@yahoo.com> and <nelson@gmail.com>')
,(2,'Alan Robert <alan.robert@gmail.com> was unassigned to <khanjoyty@gmail.com> and <katy@gmail.com>')

Select A.LogID
      ,B.* 
 From @YourTable A
 Cross Apply [dbo].[tvf-Str-Extract-JSON](LogMessage,'<','>') B

结果

LogID   RetSeq  RetVal
1       1       alan.robert@gmail.com
1       2       richard@yahoo.com
1       3       nelson@gmail.com
2       1       alan.robert@gmail.com
2       2       khanjoyty@gmail.com
2       3       katy@gmail.com

那么调整结果就成了一件小事

有兴趣的TVF

CREATE FUNCTION [dbo].[tvf-Str-Extract-JSON] (@String varchar(max),@Delim1 varchar(100),@Delim2 varchar(100))
Returns Table 
As
Return (  

    Select RetSeq = row_number() over (order by RetSeq)
          ,RetVal = left(RetVal,charindex(@Delim2,RetVal)-1)
    From  (
            Select RetSeq = [Key]+1
                  ,RetVal = trim(Value)
             From  OpenJSON( '["'+replace(string_escape(@String,'json'),@Delim1,'","')+'"]' )

          ) C1
    Where charindex(@Delim2,RetVal)>1

)

在 SQL 中使用正则表达式提取位于特殊字符之间的电子邮件

Extract Emails that Lying Between Special Characters Using Regex in SQL

sql

sql-server