create table tb(id int,score int)
insert into tb
select 1,10 union all
select 2,34
go

select *,char(ascii('A')+(id-1)%26) as word
from tb

drop table tb

/****************

id          score       word
----------- ----------- ----
1           10          A
2           34          B

(2 行受影响)

------解决方案--------------------
SQL code

select ascii('A')
--> 测试数据：[test]
if object_id('[test]') is not null drop table [test]
create table [test]([id] int,[score] int)
insert [test]
select 1,50 union all
select 2,50 union all
select 3,50

select LTRIM([id])+CHAR(64+id) as id,[score] from test

/*
id    score
1A    50
2B    50
3C    50
*/