SQL to split string and put to lower case?

Question

I have a User_Id column with data DOMAIN\USERID

I need it to be DOMAIN\userid

Whats the (sql server) sql?

Update: Answer from @David McEwing

update UserTable 
set [User_Id] = SUBSTRING( [User_Id], 0, CHARINDEX('\',  [User_Id])+1) 
        + lower(SUBSTRING( [User_Id], CHARINDEX('\',  [User_Id])+1, len( [User_Id])))

Answer 1

SELECT LEFT(User_Id, CHARINDEX('\', User_Id)) -- grabs DOMAIN and '\'
+ LOWER(RIGHT(User_Id, 
      LEN(User_Id) - CHARINDEX('\', User_Id))) -- concat with lower of userid
FROM MyTable

Answer 2

This should do the trick:

declare @name varchar(50)
set @name= 'DOMAIN\USERID'

select SUBSTRING(@name, 0, CHARINDEX('\', @name)+1) 
     + lower(SUBSTRING(@name, CHARINDEX('\', @name)+1, len(@name)))