警告：mysqli_num_rows（）要求参数1为mysqli_result，boolean

Question

这是我的php代码，用于显示有关选择地区名称的人员详细信息。

Get-NextServerName.ps1 : A parameter cannot be found that matches parameter name 'consecutiveNumbers'.

但它显示{＆＃34;错误＆＃34;：true，＆＃34; error_msg＆＃34;：＆＃34;没有数据存在＆＃34;} ...

我的表格结构如下所示

Answer 1

POST dt_name存储在变量中并在mysql查询中使用它：$ dt_name = $ _POST [＆＃39; dt_name＆＃39;];

试试这个

<?php
define('HOST','localhost');
define('USER','root');
define('PASS','');
define('DB','test');
$conn = mysqli_connect(HOST,USER,PASS,DB);

if( !$conn ) 
{
    //required post params is missing
    $response["error"] = TRUE;
    $response["error_msg"] = "Connection could not be established!";
    echo json_encode($response);
}

$dt_name = $_POST['dt_name'];
$sql = "select code,name,mobile from reg_farmer where dist_name='$dt_name'";
$res = mysqli_query($conn,$sql);

$num_rows = mysqli_num_rows($res);
//echo "$num_rows Rows\n";
if ($num_rows == 0){
     $response["error"] = TRUE;
     $response["error_msg"] = "No Data Exist";  
     echo json_encode($response); 
     exit(0);
}

$result = array();
while($row = mysqli_fetch_array($res)){
    $result = array("error" => FALSE);
    $b[]=array('code'=>$row[0],'name'=>$row[1],'mobile'=>$row[2]);
    $result["District"] = $b;
}
echo json_encode($result);
mysqli_close($conn);
?>