multiple "search" conditions

[latesh chawla]

hey there,

here's my problem:-
i have a search form..with many text fields like 'firstname', 'last name', 'city', 'state', 'country', 'location'...etc etc
now the thing is user can enter any combination in this form...
for ex: if he enters firstname to search as 'David' and lastname as 'kingston' and country as 'india'...
or he can only enter 'firstname' and 'lastname' for search........
so only these fields should be considered for search and exact same data should be retrieved from the database....
now i cant use 'AND' query with all fields since i wudnt knw which combination search would be used...nor I can use 'OR' since that wud pick up any 1 field which will return many rows resulting some duplicated or unwanted data....

I hope some one help me here with some logic...using PHP/MYSQL

Thanks in Advance...

Latesh Chawla