1、创建测试表,
create table test_ascii(value varchar2(10));
2、插入测试数据
insert into test_ascii values('a');
insert into test_ascii values('b');
insert into test_ascii values('c');
3、查询表中所有记录数,select t.*, rowid from test_ascii t,
4、编写sql,查询每个字符的ascii值,并获取最大的ascii记录,
select * from (
select t.*, ascii(value) asc_value, row_number() over(order by ascii(value) desc) rn
from test_ascii t) where rn = 1