Question

e.g,

foo1 foo2 foo10 foo100 

rather than

foo1 foo10 foo100 foo2 

Update: not interested in coding the sort myself (although that’s interesting in its own right), but having the database to do the sort for me.

Answer 1

You can use functions in your order-by clause. In this case, you can split the non-numeric and numeric portions of the field and use them as two of the ordering criteria.

select * from t  order by to_number(regexp_substr(a,'^[0-9]+')),           to_number(regexp_substr(a,'[0-9]+$')),           a; 

You can also create a function-based index to support this:

create index t_ix1     on t (to_number(regexp_substr(a, '^[0-9]+')),           to_number(regexp_substr(a, '[0-9]+$')),            a);