Building JSON Results Table FROM DB

I want to take a page like this and create a JSON table so users could look up finishers based on one or more of the following search fields:
1) First Name
2) Last Name
3) Gender
4) Age
5) Bib
6) Race Participating in

All of these fields are in a sql server db will require a JOIN of three tables.

Tables:
1) Participant (First, Last, Gender) joined by ParticipantID to
2)  PartRace (Bib, Age) joined by RaceID to
3) RaceData (Race Entered)

Let me know what else I need to tell you to purt this together.