Doesn't output last row from sql table?

Question

PHP

There is a stat table with delivery and cost columns (default = 0), I get values ​​from it row by row with a condition (if delivery = 'Mail' and cost=0), after output I make changes to the cost column, and the next time I access the table, it displays the next line that matches the condition.

//Получаю данные заказа для обработки почты
function getOne(){
    $conn = connect();
    $result = mysqli_query($conn,"SELECT * FROM `stat`  WHERE `delivery`='Почта' AND `cost`='0'");
    if (mysqli_num_rows($result)>0){
        $row= mysqli_fetch_row($result);
        $id= $row[0];
        $result2 = mysqli_query($conn,"SELECT * FROM `order`  WHERE `id`='$id'");
        $row = mysqli_fetch_assoc($result) + mysqli_fetch_assoc($result2);
        echo json_encode($row);
    }
    else {
        echo "Ошибка в getOne";
    }
    mysqli_close($conn);
}

The question is the following, everything works, but does not display any last line that meets the condition

Answer 1

You should use one query with join:

<?php
function getOne($conn) {
    $result = mysqli_query($conn,"
    SELECT * 
    FROM `stat` 
    JOIN `order` ON `order`.`id` = `stat`.`order_id` 
    WHERE `delivery`='Почта' AND `cost`='0'"
  );
  
    if (mysqli_num_rows($result)>0) {
      while ($row = mysqli_fetch_assoc($result)) {
          echo json_encode($row);
      }
    }
    else {
        echo "Ошибка в getOne";
    }
    mysqli_close($conn);
}

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