Php mysql在elseif循环中选择WHERE查询不做任何事情也没有错误

我运行我的脚本（见下文），但在设置industry&keywordrw变量的地方，它什么都没做

<?php
if (!isset($industry)) {
    $industry = '';
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings WHERE (title LIKE '%$keywordrw%' OR description LIKE '%$keywordrw%') LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    echo $keywordrw;
} elseif (!isset($keyword)) {
    $industry = $_GET['industry'];
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings WHERE category LIKE '$industry' LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    echo $industry;
} elseif (isset($keyword) && ($industry)) {
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings WHERE (title LIKE '%$keywordrw%' OR description LIKE '%$keywordrw%') AND (category = '$industry') LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    echo $keywordrw . '-' . $industry;
} else {
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    //echo $keywordrw.'-'.$industry;
}
?>

其他只设置行业的查询工作正常 另外两个涉及对关键字变量执行多个

类似的
查询，但什么都不做

<?php
if (!isset($industry)) {
    $industry = '';
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings WHERE (title LIKE '%$keywordrw%' OR description LIKE '%$keywordrw%') LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    echo $keywordrw;
} elseif (!isset($keyword)) {
    $industry = $_GET['industry'];
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings WHERE category LIKE '$industry' LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    echo $industry;
} elseif (isset($keyword) && ($industry)) {
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings WHERE (title LIKE '%$keywordrw%' OR description LIKE '%$keywordrw%') AND (category = '$industry') LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    echo $keywordrw . '-' . $industry;
} else {
    mysql_select_db($dbn, $dbc);
    $limit  = 100;
    $query  = mysql_query("SELECT * FROM listings LIMIT 0,100", $dbc);
    $result = mysql_fetch_assoc($query);
    echo mysql_error();
    //echo $keywordrw.'-'.$industry;
}
?>

更改了一些内容，下面是更新的工作代码

        if(!isset($industry))
        {
        $industry = '';
        mysql_select_db($dbn,$dbc);
        $limit = 100;
        $query = mysql_query("SELECT * FROM listings WHERE title LIKE '%keywordrw%'",$dbc);
        $result = mysql_fetch_assoc($query);
        echo mysql_error();
        } elseif(!isset($keyword)) {        
        $industry = $_GET['industry'];
        mysql_select_db($dbn,$dbc);
        $limit = 100;
        $query = mysql_query("SELECT * FROM listings WHERE category LIKE '$industry' LIMIT 0,100",$dbc);
        $result = mysql_fetch_assoc($query);
        echo mysql_error();
        } elseif(isset($keyword) &&($industry)){
        mysql_select_db($dbn,$dbc);
        $limit = 100;
        $query = mysql_query("SELECT * FROM listings WHERE (title LIKE '%$keywordrw%' OR description LIKE '%$keywordrw%') AND (category = '$industry') LIMIT 0,100",$dbc);
        $result = mysql_fetch_assoc($query);
        echo mysql_error();
        } else {
        mysql_select_db($dbn,$dbc);
        $limit = 100;
        $query = mysql_query("SELECT * FROM listings LIMIT 0,100",$dbc);
        $result = mysql_fetch_assoc($query);
        echo mysql_error();
        //echo $keywordrw.'-'.$industry;
        }