“接收”;未定义的变量:第8行C:\xampp\htdocs\xampp\products\products.php中的数据null“;
我想这是个小问题,但我希望得到解释。第8行产生未定义的变量错误(null)“接收”;未定义的变量:第8行C:\xampp\htdocs\xampp\products\products.php中的数据null“;,php,android,null,Php,Android,Null,我想这是个小问题,但我希望得到解释。第8行产生未定义的变量错误(null) 在while循环之外声明$data。若要声明$data的内部while循环作用域在while循环中,则可以在while循环外部继续使用 <?PHP include_once("connectionFile.php"); $query = "SELECT pid, name, qty, price, image_url FROM tbl_product ORDER BY pid DESC"; $result = my
在while循环之外声明$data。若要声明$data的内部while循环作用域在while循环中,则可以在while循环外部继续使用
<?PHP
include_once("connectionFile.php");
$query = "SELECT pid, name, qty, price, image_url FROM tbl_product ORDER BY pid DESC";
$result = mysqli_query($con, $query);
$data=[];
while($row = mysqli_fetch_assoc($result)){
$data[] = $row;
}
echo json_encode($data);
?>
希望它能有所帮助,因为变量
$data
没有定义
<?PHP
include_once("connectionFile.php");
$query = "SELECT pid, name, qty, price, image_url FROM tbl_product ORDER BY pid DESC";
$result = mysqli_query($con, $query);
$data = array(); // add this or $data = [];
while($row = mysqli_fetch_assoc($result)){
$data[] = $row;
}
echo json_encode($data);
您获取了0行,因此从未创建过$data
。请检查$result
中是否存在任何resultset或mysql执行错误,否则将$data
设置为空字符串/对象。
<?PHP
include_once("connectionFile.php");
$query = "SELECT pid, name, qty, price, image_url FROM tbl_product ORDER BY pid DESC";
$result = mysqli_query($con, $query);
$data = array(); // add this or $data = [];
while($row = mysqli_fetch_assoc($result)){
$data[] = $row;
}
echo json_encode($data);