Extract email address from string using tsql

Question

I\'m trying to extract email addresses from an existing comments field and put it into its own column. The string may be something like this \"this is an example comment wit

Answer 1

I know wewesthemenace already answered the question, but his/her solution seems over complicated. Why concatenate the left and right sides of the email address together? I'd rather just find the beginning and the end of the email address and then use substring to return the email address like so:

My Table

DECLARE @Table TABLE (comment NVARCHAR(50));
INSERT INTO @Table
VALUES ('blah MyEmailAddress@domain.org'),            --At the end
        ('blah MyEmailAddress@domain.org blah blah'), --In the middle
        ('MyEmailAddress@domain.org blah'),           --At the beginning
        ('no email');

Actual Query:

SELECT  comment,        
        CASE
            WHEN CHARINDEX('@',comment) = 0 THEN NULL
            ELSE SUBSTRING(comment,beginningOfEmail,endOfEmail-beginningOfEmail)
        END email
FROM @Table
CROSS APPLY (SELECT CHARINDEX(' ',comment + ' ',CHARINDEX('@',comment))) AS A(endOfEmail)
CROSS APPLY (SELECT DATALENGTH(comment)/2 - CHARINDEX(' ',REVERSE(' ' + comment),CHARINDEX('@',REVERSE(' ' + comment))) + 2) AS B(beginningOfEmail)

Results:

comment                                            email
-------------------------------------------------- --------------------------------------------------
blah MyEmailAddress@domain.org                     MyEmailAddress@domain.org
blah MyEmailAddress@domain.org blah blah           MyEmailAddress@domain.org
MyEmailAddress@domain.org blah                     MyEmailAddress@domain.org
no email                                           NULL