it all depends on what you want to search for, what results you want, which fields you want to search....
probably the easiest way is to have one text field.
then build a select query that asks each field for a match.
You can get the list of fields by 1.) supplying them explicity or 2.) Getting a list of fields from the DB.
once you have a list of fields, build a SELECT statement like...
$sql = "SELECT field1, field2 FROM table WHERE";
$criteria = array();
foreach($fieldlist as $field)
{
$criteria[$field] = $field . " LIKE '%" . $searchValue . "%'";
}
$sql .= implode(" OR ", $criteria);
echo $sql;
something like that.