INDEX possible for reverse wildcards?

If I use _reverse_ wildcard search will it always result in a table scan? Is it possible to get the DB (Oracle or SQL server) to use indexes when doing reverse wildcard match?

let's say I have:

table email_address (id int, email varchar)

with the following entries

2, www.%shoes.%
3, w%.super%shoes.%
4, %webbox.somecopany.com

select id from email_address where 'www.superdupershoes.com' like email;

this returns 2,3

But the query always results in a table scan even if I add an index to email. What kind of index can I employ in this situation?

Please note that this is a _reverse_ search, the opposite of what's normally done, i.e. select from email_address where email like 'www.%shoes.com'.

Thanks!

• Robert