嵌套的foreach循环目录和产品

Question

我有以下表格：

类别：category_id，category_name

产品：标识、类别标识、产品名称

我使用的是Bootstrap4，我想将每个类别显示为手风琴标题，并在手风琴主体中列出属于该类别的所有产品。

使用PHP7

    function getProducts(){
        $db = new DB();
        $rows = $db->db_select("SELECT category.category_id, category.category_name, products.id, products.category_id, products.product_name
                FROM products 
                INNER JOIN category ON products.id = category.category_id 
                ORDER BY category.category_name 
                ");
        if($rows === false){
            $error = db_error();
        } else {
            return $rows;
        }
    }   

$data = new CORE();
$products = $data->getProducts();



<div class="accordion" id="accordionExample">
<? foreach($products as $p){ ?>
  <div class="card">
    <div class="card-header" id="headingOne">
      <h5 class="mb-0">
        <button class="btn btn-link" type="button" data-toggle="collapse" data-target="#collapseOne" aria-expanded="true" aria-controls="collapseOne">
          <? echo $p['category_name'] ?>
        </button>
      </h5>
    </div>

    <div id="collapseOne" class="collapse show" aria-labelledby="headingOne" data-parent="#accordionExample">
      <div class="card-body">
        <? echo $p['product_name'] ?>
      </div>
    </div>
  </div>
<? } ?>
</div>

数据库数据：

Answer 1

如果将产品重新分类，请尝试此查询

$this->db->join('products','products.category_id = categories.category_id')
->order_by('categories.category_id')->get('categories')->result_array();

Answer 2

首先，我调用两个函数来获取类别和产品，如下所示。

function getCategories(){
        $db = new DB();
        $rows = $db->db_select("SELECT category.category_id, category.category_name FROM Categories");
        if($rows === false){
            $error = db_error();
        } else {
            return $rows;
        }
    }   
    function getProducts(){
        $db = new DB();
        $rows = $db->db_select("SELECT products.id, products.category_id, products.product_name
                FROM products ");
        if($rows === false){
            $error = db_error();
        } else {
            return $rows;
        }
    }   

$data = new CORE();
$categories = $data->getCategories();
$products = $data->getProducts();

然后我递归地使用这些数组在Foreach循环中。关键是，在这里我使用两个1Foreach'循环，第一个循环等待，直到第二个循环（内部）完成那里的过程。

//Take the first value of array and then second value and so on.

     foreach($Categories as $Category){

     echo $Category['name'];

//Take the first value of array and then second value and so on.

foreach($Products as $Product){

//Check the current category id with current product id. In here **category id dosent get changes untill products foreach loop completed**.

if( $Category['category_id'] == $Product['category_id'] ) {

  echo $Product['name'];
}
}
}

Answer 3

您可以将查询更改为这样的内容：

SELECTcategory.category，GROUP_CONCAT（products.id , '|', products.name）AS产品从类别INNER JOIN产品ONcategory.category_id=products.category_idGROUP BY<--代码代码


分类产品帽子8|快照，9|适合的裤子6|慢跑，7|剪裁衬衫1|马球，2|长袖，3|Vback鞋5|靴子，4|匡威