Question

我需要为多个行计算一个MySQL数据库行的列中存在的元素的数量，并将它们加在一起。这是我用来计算数组元素数量（用逗号分隔的数字）的代码：

$result = substr_count($count_fetch['micro_analysis'], ",") + 1;

但是现在我需要为每一行执行此操作，这可能会因查询而异。我需要将每一行的$result加在一起以获得所有行的最终总和。我使用了以下代码，但输入的值不正确，有人可以指出正确的方向吗？

$sql = "SELECT * FROM samples_database WHERE order_id = $order_id";

      $count_query = mysqli_query($conn, $sql);
      $count_fetch = mysqli_fetch_assoc($count_query);

      foreach ($count_fetch as $row) {
         $result = substr_count($count_fetch['micro_analysis'], ",") + 1;
         $end_result += $result;

      }

      echo $end_result;

Answer 1

用以下代码替换代码：

$sql = "SELECT * FROM samples_database WHERE order_id = $order_id";

      $count_query = mysqli_query($conn, $sql);
      $count_fetch = mysqli_fetch_assoc($count_query);
      $end_result=0;//initialize variable to 0
      foreach ($count_fetch as $k => $row) {
         if($k == 'micro_analysis'){
           $result = substr_count($row, ",") + 1; //change over here
           $end_result += $result;
         }
      }

      echo $end_result;

Answer 2

您只是获取1行，然后尝试对该行进行计数，而您需要遍历这些行并在其中添加字段...

  $sql = "SELECT * FROM samples_database WHERE order_id = $order_id";

  $end_result = 0;
  $count_query = mysqli_query($conn, $sql);
  while( $row = mysqli_fetch_assoc($count_query)) {
     $end_result += substr_count($row['micro_analysis'], ",") + 1;
  }

  echo $end_result;

如何使用php从多个数据库行中计算数字数组元素的总和？

2 个答案: