Search mysql using multiple html fields - php

Question

How do you add multiple fields to search database using html, php and mysql?
Here is the HTML code.
I would like to add more field options to search database for first name, age, gender.
Example: Search for [first name] AND/OR [Age] AND/OR [gender].
<h2>Search</h2>
<form name="search" action="searchresults.php" method="POST">
Seach for: <input type="text" name="find" /> in
<Select NAME="field">
<Option VALUE="firstName">First Name</option>
<Option VALUE="lastName">Last Name</option>
<Option VALUE="email">email</option>
</Select>
<input type="hidden" name="searching" value="yes" />
<input type="submit" name="search" value="Search" />
</form>
Here is the PHP.
Database connection
$find = strtoupper($find);
$find = strip_tags($find);
$find = trim ($find);
$find=$_POST['find'];
$field=$_POST['field'];
$data="SELECT firstName, lastName, email, userphoto, age FROM contactInfo WHERE upper($field) LIKE '%$find%'";
$result = mysql_query($data);
$count=mysql_numrows($result);
echo '<br><br>';
if($count > 0){
echo"<table border=0>";
//get images and names in two arrays
$firstName= $row["firstName"];
$lastName= $row["lastName"];
$email= $row["email"];
$userphoto= $row["userphoto"];
$age= $row["age"];
$age = array();
$userphoto = array();
$firstName = array();
$lastName = array();
while ($row = mysql_fetch_array($result))
{
$userphoto[] = "<img src='images/".$row['userphoto']."' height='200' width='175'>";
$firstName[] = $row['firstName'];
$lastName[] = $row['lastName'];
$age[] = $row['age'];
$email[] = $row['email'];
}
while(!empty($userphoto))
{
//output images
foreach(array($userphoto, $firstName, $lastName, $age, $email) as $items)
{
echo "<tr>";
foreach($items as $key=>$item)
{
echo "<td><font size =\"3\" >$item</td>";
//output only four of them
if($key==4)
{
break;
}
}
echo "</tr>";
}
//remove the first five images from $images because they're already printed
$userphoto = array_slice($userphoto, 5);
$firstName = array_slice($firstName, 5);
$lastName= array_slice($lastName, 5);
$email = array_slice($email, 5);
$age = array_slice($age, 5);
}
echo"</table>";

Answer 1

I would divide the query in two parts:
First create a static part:
$query = "SELECT firstName, lastName, email, userphoto, age FROM contactInfo WHERE"
And then calculated the dinamic part:
For each field select by the user according to the and/or option:
$query = $query . $nameField . ("and" || "or") . $valueField

Answer 2

Change Your query.
$data="SELECT firstName, lastName, email, userphoto, age FROM contactInfo WHERE `".$field."` LIKE '%".$find."%'";