Alter the letters after "ACCOUNTS\" to lower case?

Question

I have a database table, users, with different username cases (see the example). How can I update the letters after ACCOUNTS\ to lower case?

ACCOUNTS\James.McAvoy
ACCOUNTS\michael.fassbender
ACCOUNTS\nicholas.hoult
ACCOUNTS\Oscar.Isaac

Desired result after the update:

ACCOUNTS\james.mcavoy
ACCOUNTS\michael.fassbender
ACCOUNTS\nicholas.hoult
ACCOUNTS\oscar.isaac

Answer 1

UPDATE dbo.[User]
SET username_column = N'ACCOUNTS' + LOWER(SUBSTRING(username_column, 9, 4000))
WHERE username_column LIKE 'ACCOUNTS\%';

Answer 2

Replace and Lower should do the job here.

UPDATE dbo.User SET username = 'ACCOUNTS\' + LOWER(REPLACE(username, 'ACCOUNTS\', ''))