綁定中的參數與綁定字段的數量不匹配？

Question

我使用mysqli來執行db查詢。這是我的代碼：

if($stmt = $connection->prepare("SELECT * FROM table1 WHERE code = ?")) 
{ 
    $find = "Op"; 
    $stmt->bind_param("s", $find); 
    $stmt->execute(); 
    $stmt->bind_result($res); 
    $stmt->fetch(); 
    echo "Res => " . $res; 
    $stmt->close(); 
} 

現在的問題是，在這條線：$stmt->bind_param("s", $find); 我得到這個錯誤：

Warning: mysqli_stmt::bind_param(): Number of elements in type definition string doesn't match number of bind variables

注：$connection包含與數據庫建立連接。我做錯了什麼？

Answer 1

你的bind_param()方法很好。問題是這種說法，

$stmt->bind_result($res); 

在SELECT聲明你正在做SELECT * FROM ...但在->bind_result()方法你想結果只有一個列與變量綁定$res。

所以你prepare()的說法應該是這樣的：

$stmt = $connection->prepare("SELECT column1 FROM table1 WHERE code = ?") 

以後，如果你想通過它循環，你可以這樣做：

while ($stmt->fetch()) { 

    // your code 
    // echo $res . "<br />"; 

} 

Answer 2

按照這樣的正確方法：

<?php 
/* Execute a prepared statement by binding PHP variables */ 
$calories = 150; 
$colour = 'red'; 
$sth = $dbh->prepare('SELECT name, colour, calories 
    FROM fruit 
    WHERE calories < ? AND colour = ?'); 
$sth->bindParam(1, $calories, PDO::PARAM_INT); 
$sth->bindParam(2, $colour, PDO::PARAM_STR, 12); 
$sth->execute(); 
?> 

在你的情況下，它會是這樣：修改

if($stmt = $connection->prepare('SELECT * FROM table1 WHERE code = ?')) 
{ 
    $find = 'Op'; 
    $stmt->bind_param(1, $find, PDO::PARAM_STR); 
    $stmt->execute(); 
    // Fetch column data 
    // $result = $sth->fetchColumn(2); 
    // Fetch all data 
    // $result = $sth->fetchAll(); 
    // echo "<pre>"; 
    // print_r($result); 
    // Fetch only some columns data. 

    $stmt->bindColumn(2, $cals); 

    while ($row = $stmt->fetch(PDO::FETCH_BOUND)) { 
     print $cals . "</br>"; 
    }  
} 

注：

You can specify, how many column data you want.

例子：

You have columns like colone, coltwo, colthree, colfour in your table. You write query : select * from tablename. Now you want to show only 2 column (colone,colthree), you can use bindcolumn(). You have to use like this : $stmt->bindColumn('colone', $cal1);$stmt->bindColumn('colthree', $cal3);*