php - 我正在尝试从数据库中提取数据，其中数据将从数据库中的两个不同表中提取，错误位于 $returns = mysql_query

Question

我试图从数据库中的两个不同表中提取数据，但仍然出现错误。当我运行代码时它不显示任何内容

这是我的代码:

<?php 
$st="";
$sc="";

    if (isset($_POST['submit']) && $_POST['submit'] == "submit"){
       $st=$_POST['s-t'];
       $sc= "WHERE nums like \"%$st%\"  or d_n like \"%st%\" ";
    }


    if (isset ($_GET['look']) && $_GET ['look'] != "") {
       $st=$_GET['look'];
       $sc = "WHERE nums like \"%$st%\"  or d_n like \"%st%\" ";
     }

    $db = mysql_db_connect();
    $rpp = 50;

    if (isset($_GET['page'])){

    $pn = $_GET['page'];
    $begin = ($rpp*$pn)-$rpp;
    $finish=($rpp*$pn);
    $finish=50;
} 
else {
    $pn =1;
    $begin = 0;
    $finish =$rpp;
} 

    $returns = mysql_query ("SELECT * FROM  extenz $sc", $db);
    $numer_rows = mysql_num_rows($returns);
    $number_pages = ((int) ($numer_rows/$rpp)) +1;

    if (($number_rows % rpp) ==0){
    $number_pages=$number_pages -1;
}
$returns = mysql_query("SELECT nums, name , p_m FROM extenz, P_exten  left join p_exten on extenz $sc order by nums & P_m LIMIT $begin, $finish", $db);

?> 

Answer 1

我回答了我的问题

错误出现在以下代码行

$returns = mysql_query("SELECT nums, name , p_m FROM extenz, P_exten  left join p_exten on extenz $sc order by nums & P_m LIMIT $begin, $finish", $db);

更正为

$returns = mysql_query("SELECT extenz.nums, extenz.name,p_exten.P_M FROM extenz LEFT JOIN ON  p_exten.extenz=extenz.nums $sc ORDER BY nums LIMIT $begin, $finish",$db);