Question

I am trying to create a query where a user can enter: first name, last name, nick name, grade, and gender. However, some of these fields may be empty.

I know how to create a query that will check all of those. However, how can I make it where it won’t query for something if it’s not given. For example, a user might want to search by last name and gender, but not the others.

How can I go about doing this? Thanks so much for the help!

@Ibu, this is what I have so far:

// Now we need to query the database for these terms
$sql_query = "SELECT * FROM `students` WHERE `first_name` = '" . $first_name . "' AND `last_name` = '" . $last_name . "' AND `nick_name` = '" . $nick_name . "' AND `grade` = '" . $grade . "' AND `gender` = '" . $gender . "'";
$result = mysql_query($sql_query);

// Let's check to make sure there is an actual result
$num_rows = mysql_num_rows($result);

if($num_rows < 1) {
    echo 'No student was found using that criteria.';
}

if($num_rows >= 1) {
    echo '<p>' . $num_rows . ' result(s) found. Below are the results:</p>';
    echo '<br />';
}

while($row = mysql_fetch_array($result)) {
    echo '
        <table border="1" width="400">
        <tr>
            <td colspan="2" align="center">Student Profile - ' . $row['last_name'] . ', ' . $row['first_name'] . '</td>
        </tr>
        <tr>
            <td>First Name: </td>
            <td>' . $row['first_name'] . '</td>
        </tr>
        <tr>
            <td>Last Name: </td>
            <td>' . $row['last_name'] . '</td>
        </tr>
        <tr>
            <td>Nick Name: </td>
            <td>' . $row['nick_name'] . '</td>
        </tr>
        <tr>
            <td>Grade: </td>
            <td>' . $row['grade'] . '</td>
        </tr>
        <tr>
            <td>Gender: </td>
            <td>' . $row['gender'] . '</td>
        </tr>
        </table> <br /><br />';

}

Answer 1

Just check the $_POST vars and build the query on that.

Like this for example (this bad in that it does not sanitize the $_POST for injection, but its a good start):

$whereSet = false;
$where = '';
if(isset($_POST['name'])){
    $whereSet = true;
    $where .= "WHERE name = '{$_POST['name']}'\n";
}
if(isset($_POST['nick'])){
    if(!$whereSet){
        $where .= "WHERE ";
        $whereSet = true;
    }
    else {
        $where .= "AND ";
    }
    $where .= "nick = '{$_POST['nick']}'\n";
}
//...etc

Then just append the $where variable to the end of your query