如何在现有的SQL数据库（PHP）中添加另一个查询

Question

一个网站已经传递给我和我的IT同班同学，我们目前在OJT上，最近我们正在处理一个Android项目。对此我们感到生疏和过时，请提供帮助。

-问题：警告：mysql_num_rows（）期望参数1为资源，在第21行的C：\ xampp \ b \ htdocs \ alumni_mod \ admin \ dbOp.php中给出布尔值

<?php
include "db.php";
function dispAnnounce(){
$disp="";
adb();
$query=mysql_query("SELECT title,content FROM announce ORDER BY date_created DESC");
$limit=mysql_num_rows($query);
if ($limit==0){
    $disp.="No current announcement!";
}
else {
    for($j=1;$j<=$limit;$j++){
        $row=mysql_fetch_object($query);
        $disp.="<div id='aTitle'>".$row->title."</div>";
        $disp.="<div id='aContent'>".$row->content."</div>";
    }
}
endadb();
echo $disp;
}
function dispContent($content)/*this is line 21*/{
$disp="";
adb();
if ($content=="offname"){
    $query=mysql_query("SELECT title,content FROM offname");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current official name!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
 }elseif ($content=="objective"){
    $query=mysql_query("SELECT title,content FROM objective");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current objectives!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
 }elseif ($content=="ongoing"){
    $query=mysql_query("SELECT title,content FROM ongoing");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current on going events!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
 }elseif ($content=="other"){
    $query=mysql_query("SELECT title,content FROM other");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current other projects!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
 }elseif ($content=="sec"){
    $query=mysql_query("SELECT title,content FROM sec order by id desc");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current SEC!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
 }elseif ($content=="upcoming"){
    $query=mysql_query("SELECT title,content FROM upcoming order by id desc");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current upcoming events!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="hist"){
    $query=mysql_query("SELECT title,content FROM history");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current history!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='dTitle'>".$row->title."</div>";
            $disp.="<div id='dContent'>".$row->content."</div>";
        }
    }
}

elseif ($content=="law"){
    $query=mysql_query("SELECT title,content FROM law order by id desc");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current By Laws!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="foun"){
    $query=mysql_query("SELECT title,content FROM founofficer order by id desc");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current foundation officers!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="col"){
    $query=mysql_query("SELECT title,content FROM colofficer order by id desc");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current college officers!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="hs"){
    $query=mysql_query("SELECT title,content FROM hs order by id desc");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current past events!!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="scholar"){
    $query=mysql_query("SELECT title,content FROM scholar order by id desc");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current scholar!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="contact"){
    $query=mysql_query("SELECT title,content FROM contact");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current contacts!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="elem"){
    $query=mysql_query("SELECT title,content FROM elemofficer");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current elementary officers!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
elseif ($content=="aqueen"){
    $query=mysql_query("SELECT title,content FROM aqueen ORDER BY date_created DESC");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No current alumni queen!";
    }
    else {
        for($j=1;$j<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
        }
    }
}
/*this part here is what I'm going to add*/
elseif($content=="former"){
    $query=mysql_query("SELECT title,content FROM formerpres");
    $limit=mysql_num_rows($query);
    if ($limit==0){
        $disp.="No former president!";
    }
    else{
        for($j=1;<=$limit;$j++){
            $row=mysql_fetch_object($query);
            $disp.="<div id='hTitle'>".$row->title."</div>";
            $disp.="<div id='hContent'>".$row->content."</div>";
    }   
    }
    }

    endadb();
return $disp;

} ？>

/*db.php*/
<?php
function adb(){
global $con;
try {
    $host = "localhost";
    $user = "webalumni";
    $pwd = "s1j2c3a4l5u6m7n8i9";
    $db = "alumnidb";
    $con = mysql_connect($host,$user,$pwd);
    $select = mysql_select_db($db, $con);
}
catch(Exception $e){
    echo "Error Found:";
}
}
function endadb(){
global $con;
mysql_close($con);
}
?>

Answer 1

根据documentation：

  

对于SELECT，SHOW，DESCRIBE，EXPLAIN和其他返回结果集的语句，mysql_query（）成功时返回资源，错误时返回FALSE。

因此，很可能查询是错误的。

我希望我有所帮助：）