How do I replace a substring of a string before a specific character?

Question

Table Email:

Values:

[email protected]
[email protected]
[email protected]

I want to replace the string before @ with test.

Result:

[email protected]
[email protected]
[email protected]

How do I use substringing and replace based on a character in the string?

Answer 1

declare @t table(email varchar(30))
insert @t values('[email protected]'),
                ('[email protected]'),
                ('[email protected]') 

select stuff(email, 1, charindex('@', email), 'Test@') 
from @t

Result:

[email protected]
[email protected]
[email protected]

Answer 2

You don't even need to use substring or replace, you can use this:

SELECT 'test' + RIGHT(email, charindex('@', REVERSE(email)))
FROM YourTable

You can test it out with this:

DECLARE @email nvarchar(50)
SET @email = '[email protected]'
PRINT 'test' + RIGHT(@email, charindex('@', REVERSE(@email)))

Answer 3

You can use SUBSTRING and CHARINDEX:

UPDATE Email set email = 
    'test' + SUBSTRING(email, CHARINDEX('@',email), LEN(email))

Fiddle: http://sqlfiddle.com/#!3/0face/6/0