SQL & PL/SQL :: Sort By Best Match

Suppose I have a table in which I have first_name, last_name, dob. Now I have to fetch on the basis of first_name=some_value, last_name=some_value and dob=some_date. I want to sort it on the basis of exactly fetched values. Let me take an example-

test table contains-

first_name last_name dob
---------- --------- ----
Manu Batham 02-Feb-1988
Manu Sharma 01-Jul-1987
Avinash Pandey 03-Feb-1988
Ankit Gupta 02-Feb-1988
Manu Aggrawal 02-Feb-1988
Manu Batham 20-Jan-1985
Sikha Batham 17-Apr-1988

Now if I give parameters-

first_name='Manu'
last_name='Batham'
dob='02-Feb-1988'

then my result should be like below-

result-

first_name last_name dob
---------- --------- ----
Manu Batham 02-Feb-1988
Manu Aggrawal 02-Feb-1988
Manu Batham 20-Jan-1985
Manu Sharma 01-Jul-1987
Ankit Gupta 02-Feb-1988
Sikha Batham 17-Apr-1988

My result is based on the approach-
if matched first_name, last_name, dob --> 1st prefrence in order
if matched first_name, dob --> 2nd prefrence in order
if matched first_name, last_name --> 3rd prefrence in order
if matched last_name, dob --> 4th prefrence in order
if matched first_name --> 5th prefrence in order
if matched last_name --> 6th prefrence in order
if matched dob --> 7th prefrence in order

I designed the following query for the same-

Select first_name,last_name,dob,1 "Order" from test Where
first_name='Manu' and
last_name='Batham' and
dob=to_date('02/02/1988','dd/mm/yyyy')
union
Select a,b,c,2 from test Where
[code]......

I know that this is not the best possible solution as the table is very big and doing so many hits on that table will certainly decrease the performance.