Replace Character Without Using Looped REPLACE Function

My SQL Server database input values follow a pattern of where the first position is a character and then followed by number. I want replace the first character with another character or characters . For example:

input

• Q234567888

• R264747848

• B264712481

output

• I234567888

• I264747848

• U264712481

Potential values for the first position are [A-Z].

I am looking for an option without using multiple REPLACE statement and not using CASE.

If I use CASE, I will have to check 26 cases or if I use REPLACE in a nested way, I may end up using 26 REPLACE statements. I am trying to avoid these.

Please suggest any better way to do achieve the results.

Create a mapping between the old value and the new value in a table value constructor and use stuff to replace the character.

declare @T table(Value varchar(10));

insert into @T values
('Q234567888'),
('R264747848'),
('B264712481');

select stuff(T.Value, 1, 1, (
                            select V.NewValue
                            from (values('Q', 'I'),
                                        ('R', 'I'),
                                        ('B', 'U')) as V(OldValue, NewValue)
                            where V.OldValue = left(T.Value, 1)
                            ))
from @T as T;

StackExchange Database Administrators Q#201851, answer score: 7