未定義的變量mysql-php

Question

我花了兩個小時試圖解決錯誤所以最後問了這個問題。

我的表是這樣的

tablename- schemeOverview 

    | slno |schemename | amount| date2 | date3 | date4 |collected | 
    |---------|-----------|-------|-------|-------|-------|----------| 
    | 1 | Cell  | 1000 | DUE | DUE |  | 0  | 
    | 2 | Cell  | 1000 | PAID | PAID |  | 0  | 
    | 3 | Cell  | 1000 | DUE | DUE | DUE | 0  | 
    | 4 | Cell  | 1000 | PAID | PAID |  | 100  | 
    | 5 | Cell  | 1000 | DUE | DUE |  | 0  | 

the table was created in phpmyadmin and the default value for collected is 0. 

我試圖獲取指定schemename收集費爾德的價值。

這裏是代碼

echo "$scheme_name"; 
$sql12 = " SELECT collected FROM schemeOverview WHERE schemename = '".$scheme_name."'"; 
$reslut12 = mysqli_query($conn,$sql12); 
var_dump($result12); 
if(!$result12) 
{ 
echo "Error fetching data: " .mysqli_error($conn); 
} 
else{ 
echo "Success"; 
} 
while ($row12 = $result12->fetch_assoc()) 
{ 
     var_dump($row12); 

} 

這是錯誤我得到

sapneshad 
Notice: Undefined variable: result12 in E:\xampp\htdocs\insertPayment.php on line 195 
NULL 
Notice: Undefined variable: result12 in E:\xampp\htdocs\insertPayment.php on line 196 
Error fetching data : 
Notice: Undefined variable: result12 in E:\xampp\htdocs\insertPayment.php on line 203 

Fatal error: Uncaught Error: Call to a member function fetch_assoc() on null in E:\xampp\htdocs\insertPayment.php:203 Stack trace: #0 {main} thrown in E:\xampp\htdocs\insertPayment.php on line 203 

Answer 1

您有一個錯字（$reslut12）。已更正的代碼版本：

echo "$scheme_name"; 
$sql12 = " SELECT collected FROM schemeOverview WHERE schemename = '".$scheme_name."'"; 
$result12 = mysqli_query($conn,$sql12); 
var_dump($result12); 
if(!$result12) 
{ 
    echo "Error fetching data: " .mysqli_error($conn); 
} 
else{ 
    echo "Success"; 
} 
while ($row12 = $result12->fetch_assoc()) 
{ 
    var_dump($row12); 
} 

Answer 2

這是一個簡單的拼寫錯誤（該UI被逆轉，在結果）：

「$reslut12」 應be「$result12」

更新的代碼：

echo "$scheme_name"; 
$sql12 = " SELECT collected FROM schemeOverview WHERE schemename = '".$scheme_name."'"; 
$result12 = mysqli_query($conn,$sql12); 
var_dump($result12); 
if(!$result12) 
{ 
echo "Error fetching data: " .mysqli_error($conn); 
} 
else{ 
echo "Success"; 
} 
while ($row12 = $result12->fetch_assoc()) 
{ 
     var_dump($row12); 

}