How to trim everything after certain character in sql

Question

I am trying to format the email address in my table by removing everything starting the @. Also I would like to replace the underscore with blank space.

For exampl

Answer 1

SELECT REPLACE(LEFT(Email, CHARINDEX('@',Email)-1),'_',' ')
FROM [DSR].[dbo].[RCA_Dashboard]

Answer 2

This can be helpful if you need to remove all after the last certain character:

Declare @String nvarchar(max) = 
  'C:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\log.ldf'


select reverse(substring(reverse (@String), CHARINDEX('\', reverse (@String))+1, len(reverse (@String))));