Unable to display variable?

T

Tati_922020-05-18 11:53:12

PHP

Tati_92, 2020-05-18 11:53:12

I am newbie! I'm learning how to create an online store from a video tutorial. The task is to display a specific brand from the database by clicking on the buttons:

<button id="button_brand" > 
<a id="button_brand2" href="view_goods_brand.php?cat='.strtolower($row["name"]).'">'.$row["name"].' посмотреть косметику </a></button>

I create a $cat variable in the view_goods_brand.php file and by checking echo "Condition:"+$cat; - $ cat = 0 is obtained and an error is thrown:

Warning: mysqli_num_rows() expects parameter 1 to be mysqli_result, boolean given in W:\domains\korea.ru\view_goods_brand.php on line 116

file view_goods_brand.php:

<!DOCTYPE html>

<html >
 <head>
    <?php
    
  include('includes/db.php');//Подключаю БД
  
  $cat =  $_GET["cat"];
  

    $sorting = $_GET["sort"];
         
    switch ($sorting) {
    
        case 'price-asc';
    $sorting = 'price ASC';
    $sort_neme = 'От дешевых к дорогим';
      break;
    
    case 'price-desc';
    $sorting = 'price DESC';
    $sort_neme = 'От дорогих к дешевым';
      break;
    
    case 'popular';
    $sorting = 'count DESC';
    $sort_neme = 'Популярные';
      break;
    
    case 'news';
    $sorting = 'datetime DESC';
    $sort_neme = 'Новинки';
      break;
    
    case 'brand';
    $sorting = 'brand DESC';
    $sort_neme = 'Бренд';
      break;
    
        default:
    $sorting = 'datetime DESC';
    $sort_neme = 'Нет сортировки';
        break;		
  }
  
  ?>

  <meta charset="utf-8"/>
 
  <meta name="viewport" content="width=device-width,initil-scale=1"/> <!-- ДЛЯ МОБИЛЬНЫХ УСТРОЙСТВ -->
  
  <link href="css/stil.css" rel="stylesheet" type="text/css"/>  <!-- ССЫЛКА НА CSS -->
  <link href="css/media.css" rel="stylesheet" type="text/css"/>  <!-- ССЫЛКА НА CSS -->

 
  
  <title>Косметика для лица</title><!-- Название веб-страницы -->

  <?php require "header.php"; ?>
  
  </head> 
  <div  id="topbutton">&#8593;<br/>Наверх</div> 
 
 <body>
  
  
  <div id="conteiner">   
  <div id="conteiner-goods">
  
  <div id="floatingBarsG">
  <div class="blockG" id="rotateG_01"></div>
  <div class="blockG" id="rotateG_02"></div>
  <div class="blockG" id="rotateG_03"></div>
  <div class="blockG" id="rotateG_04"></div>
  <div class="blockG" id="rotateG_05"></div>
  <div class="blockG" id="rotateG_06"></div>
  <div class="blockG" id="rotateG_07"></div>
  <div class="blockG" id="rotateG_08"></div>
</div>



  <p id="view">Вид:</p>
  <a href="#"> <img  id="box_list1" src="image/nav/box-list.png" alt="img"/></a>
  <a href="#"> <img  id="box_list2" src="image/nav/box1.png" alt="img"/></a>
  
  <p id="sort">Cортировать:</p>
  <a id="link"><?php echo $sort_neme; ?></a>
  <div id="sort_block">
  <a href="for_face.php?sort=price-asc">От дешевых к дорогим</a><br>
  <a href="for_face.php?sort=price-desc">От дорогих к дешевым</a><br>
  <a href="for_face.php?sort=popular">Популярные</a><br>
  <a href="for_face.php?sort=news">Новинки</a><br>
  <a href="for_face.php?sort=brand">Бренд</a>
  </div>
  
 <div id="single_goods_block"> 
 
 <?php

 if (!empty($cat))
 {
   $querycat = "brand='$cat'";
 }else{
   if(!empty ($cat)){

     $querycat='';
   }
 }
  echo "Условие:"+$cat;
  
  
 $result =  mysqli_query($link, "SELECT * FROM  teble_products  $querycat  ORDER BY  $sorting");//выводим товары
    
  if (mysqli_num_rows($result) > 0) {
    $row = mysqli_fetch_array($result);
    do {
      echo('
   
   
   <div id="goods_block">
      <img class="img_face" src="image/goods/fase/'.$row["image"].'"/>
    
    <p class="style_title"><a href="#">' . $row["title"] . '</a> </p> 
    <hr>
      
    <a data-tooltip="Просмотры"><img id="reviews" src="image/nav/eye.png"/><p id="reviews_quantity">0</p></a>
    
    <a data-tooltip="Добавить в Избранные"><p id="heart_quantity">0</p> <img id="heart" src="image/nav/heart.png"/></a>
    
    <p class="price_goods_face"><strong> '.$row["price"].' </strong> руб.</p> 
    
    <a href="http://korea.ru/cart.php" data-tooltip="Корзина">
    <img  id="cart_goods_face"src="image/Box pink-256.png" alt="img"/>
    <p id="cart_quantity">0</p>
    </a> 
    
    
    <div class="mini_description"> '.$row["mini_description"].'</div>
    </div>     
    	
    
    ');
    }
    while ($row = mysqli_fetch_array($result));
  }
 ?>

   </div>
 

 <div id="single_goods_line"> 
  
 <?php
 
 if (!empty($cat))
 {
   $querycat = "brand = '$cat'";
 }

 $result =  mysqli_query($link, "SELECT * FROM  teble_products  $querycat ORDER BY  $sorting");//выводим товары
    
  if (mysqli_num_rows($result) > 0) {
    $row = mysqli_fetch_array($result);
    do {
    
  
      echo('
   
   
   <div id="goods_block_line">
      <img class="img_face_line" src="image/goods/fase/'.$row["image"].'"/>
    
    <p class="style_title_line"><a href="#">' . $row["title"] . '</a> </p> 
    
      
    <a data-tooltip="Просмотры"><img id="reviews_line" src="image/nav/eye.png"/><p id="reviews_quantity_line">0</p></a>
    
    <a data-tooltip="Добавить в Избранные"><p id="heart_quantity_line">0</p> <img id="heart_line" src="image/nav/heart.png"/></a>
    
        <a href="http://korea.ru/cart.php" data-tooltip="Корзина">
    <img  id="cart_goods_face_line"src="image/Box pink-256.png" alt="img"/>
    <p id="cart_quantity_line">0</p>
    </a>
    
    <p class="price_goods_face_line"><strong> '.$row["price"].' </strong> руб.</p> 
    
    <div class="description_line"> '.$row["description"].'</div>
    </div>     
    	
    
    ');
    }
    while ($row = mysqli_fetch_array($result));
  }
 ?>


   </div>
   </div>
</div>
   
   <script type="text/javascript" src="js/jquery-3.4.1.min.js"></script> <!--  подключается первым -->

   <script type="text/javascript" src="js/goods.js"></script>
  
   <script type="text/javascript" src="js/script.js"></script><!--подключается вторым-->
   
 </body> 
  <?php include "footer.php"; ?>

 
</html>

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1 answer(s)

F

FanatPHP, 2020-05-18
@Tati_92

Your sorting is done normally, but filtering through one place.
And for God's sake, throw out these video courses from Ruseller, they won't teach you anything normal, you'll become a kid.

<?php
 
 if (!empty($cat))
 {
    $cat = mysqli_real_escape_string($link, $cat);
    $querycat = "WHERE brand = '$cat'";
 }

 $result =  mysqli_query($link, "SELECT * FROM  teble_products  $querycat ORDER BY  $sorting");//выводим товары
  while ($row = mysqli_fetch_array($result)) { 
   
  
      echo('
   
   
   <div id="goods_block_line">
      <img class="img_face_line" src="image/goods/fase/'.$row["image"].'"/>
    
    ');
  }
 ?>