Ajax搜索框：MySQL错误[重复]

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                        <a href="/questions/12769982/reference-what-does-this-error-mean-in-php" dir="ltr">Reference - What does this error mean in PHP?</a>
                            <span class="question-originals-answer-count">
                                (36 answers)
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                        <a href="/questions/2973202/mysql-fetch-array-mysql-fetch-assoc-mysql-fetch-row-mysql-num-rows-etc" dir="ltr">mysql_fetch_array()/mysql_fetch_assoc()/mysql_fetch_row()/mysql_num_rows etc… expects parameter 1 to be resource</a>
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                                (31 answers)
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            <div class="grid--cell mb0 mt8">Closed <span title="2013-10-01 14:27:53Z" class="relativetime">6 years ago</span>.</div>
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I'm trying to create a search box using ajax and php. For some reason I get

"Warning: mysql_fetch_array() expects parameter 1 to be resource, boolean given in C:\wamp\www\livesearch\livesearch.php on line 30"

on the following code:

session_start();
include("_/inc/dbcon.php");
    $link = mysql_connect($host, $login, $pw);
    mysql_select_db($database);
    if($link){
     echo 'connect';
    }
// Define Output HTML Formating
$html = '';
$html .= '<li class="result">';
$html .= '<a target="_blank" href="urlString">';
$html .= '<h3>nameString</h3>';
$html .= '<h4>functionString</h4>';
$html .= '</a>';
$html .= '</li>';

// Get Search
$search_string = preg_replace("/[^A-Za-z0-9]/", " ", $_POST['query']);
$search_string = mysql_real_escape_string($search_string);

// Check Length More Than One Character
if (strlen($search_string) >= 1 && $search_string !== ' ') {
    // Build Query
    $query = 'SELECT * FROM sp_user WHERE function LIKE "%'.$search_string.'%" OR name LIKE "%'.$search_string.'%" OR surname LIKE "%'.$search_string.'%" OR username LIKE "%'.$search_string.'%"';

    // Do Search

    $result = mysql_query($query);
    while($results = mysql_fetch_array($result)) {
        $result_array[] = $results;
    }

    // Check If We Have Results
    if (isset($result_array)) {
        foreach ($result_array as $result) {

            // Format Output Strings And Hightlight Matches
            $display_function = preg_replace("/".$search_string."/i", "<b class='highlight'>".$search_string."</b>", $result['function']);
            $display_name = preg_replace("/".$search_string."/i", "<b class='highlight'>".$search_string."</b>", $result['name']);
            $display_url = 'http://php.net/manual-lookup.php?pattern='.urlencode($result['function']).'&lang=en';

            // Insert Name
            $output = str_replace('nameString', $display_name, $html);

            // Insert Function
            $output = str_replace('functionString', $display_function, $output);

            // Insert URL
            $output = str_replace('urlString', $display_url, $output);

            // Output
            echo($output);
        }
    }else{

        // Format No Results Output
        $output = str_replace('urlString', 'javascript:void(0);', $html);
        $output = str_replace('nameString', '<b>No Results Found.</b>', $output);
        $output = str_replace('functionString', 'Sorry :(', $output);

        // Output
        echo($output);
    }

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