Form output using mysql, search people name in specific category

I have search php forms that connecting to mysql, for search people name in all category and search people name in specific category
People name field in mysql : people_name , example : John, Michael, etc
category name field in mysql : people_category , example : Kid, Adult, etc

I can Search All People name using first option value below, for example i search : John
beside that i want to search : John only in adult category
what is the right code so i can get people name just from adult category

Quote:
<select name="metode" size="1">
<option value="people_name">Search All People</option>
<option value="people_name_just_from_adult_category">Search People By Category</option>
</select>
<input type="text" name="search" size="25">
<input type="submit" value="Search" name="Go" />


Please share your php mysql knowledge here