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

Question

Table Email:

Values:

josh@yahoo.com
carmine32@hotmail.com
zehmaneh@yahoo.com

I want to replace the string before

Answer 1

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