ci search based on parameters user selects

[eluser]ravindral[/eluser]
Hello all CI lovers,
Sorry but it is urgent, i have to deliver the project. As this is my first project in CI, i dont know how to do search engine. Lets say i have country, city and subject parameters. So based on selection of combinations, i have to show search result of teachers.
Lets say user selects UK and Workshire as city OR UK and maths as 2 parameters. I dont know which combination out of 3 user will select. So how should i handle search?

Thanks,
Ravindra