[英]MySQLi prepared statement issue
我正在(嘗試)將查詢從未准備好的語句移到MySQLi准備好的語句。 到目前為止,我所學到的應該以以下方式發生:
$post_id = $mysqli->real_escape_string($_GET['id']);
$query_blog = 'SELECT * FROM blog WHERE id = ?';
$result_blog = $mysqli->prepare($query_blog);
$result_blog->bind_param('i', $post_id);
$result_blog->execute();
$result_blog->bind_result();
$result_blog->close();
$mysqli->close();
如果我回顯$ post_id和$ query_blog,我得到正確的結果。 但是當涉及bind_param時,它會卡住。 不知道有什么問題。 任何想法如何運行此?
總的來說,我的代碼如下所示:
<?php
$post_id = $mysqli->real_escape_string($_GET['id']);
$query_blog = 'SELECT * FROM blog WHERE id = ?';
$result_blog = $mysqli->prepare($query_blog);
$result_blog->bind_param('i', $post_id);
$result_blog->execute();
$result_blog->bind_result();
$result_blog->close();
$mysqli->close();
if ($result_blog):
if(mysqli_num_rows($result_blog)>0):
while($blog_entry = mysqli_fetch_assoc($result_blog)):
//Do something
endwhile;
endif;
endif;
非常感謝!
編輯:如果我准備語句后,我print_r得到:
mysqli_stmt Object ( [affected_rows] => 0 [insert_id] => 0 [num_rows] => 0 [param_count] => 1 [field_count] => 7 [errno] => 0 [error] => [error_list] => Array ( ) [sqlstate] => 00000 [id] => 1 )
如果我在bind_param之后使用print_r,則會得到以下語句:
mysqli_stmt Object ( [affected_rows] => 0 [insert_id] => 0 [num_rows] => 0 [param_count] => 1 [field_count] => 7 [errno] => 0 [error] => [error_list] => Array ( ) [sqlstate] => 00000 [id] => 1 )
如果我在執行語句后使用print_r,則會得到:
mysqli_stmt Object ( [affected_rows] => -1 [insert_id] => 0 [num_rows] => 0 [param_count] => 1 [field_count] => 7 [errno] => 0 [error] => [error_list] => Array ( ) [sqlstate] => 00000 [id] => 1 )
所以受影響的行更改為-1是否表示沒有找到ID = 1的行,因為這肯定在我的數據庫中。
編輯2:
如果添加以下語句,我將從查詢中獲取數據。
$result_blog->bind_result($id, $headline);
$result_blog->fetch();
print_r($headline);
但是如何循環顯示結果?
if ($result_blog):
if(mysqli_num_rows($result_blog)>0):
while($blog_entry = mysqli_fetch_assoc($result_blog)):
//Do something
endwhile;
endif;
endif;
這似乎不起作用:-/
一個准備好的語句的簡單示例如下所示:
// Set query
$query = "SELECT field_1, field_2 FROM table WHERE field_3 = ?";
// prepare statement
$stmt = mysqli->prepare($query);
// bind param (marked with '?' in $query) and define type
// look [http://php.net/manual/de/mysqli-stmt.bind-param.php] for further information for this function
$stmt->bind_param('i', $foo);
// define variables which will contain content after fetching the result
$stmt->bind_result($field_1, $field_2);
// execute query and check if successful
if($stmt->execute() === false)
{
// an error occurred, do something!
// throw new Exception('error!');
}
// loop through results
while($stmt->fetch())
{
// this part will be executed for every result
// do something with $field_1 and $field_2
}
// release memory
$stmt->close();
對於您的代碼,可能看起來像這樣:
$query = "SELECT id, headline FROM blog WHERE id = ?";
$stmt = mysqli->prepare($query);
// assuming that $_GET['id'] is an integer
$stmt->bind_param('i', $_GET['id']);
$stmt->bind_result($id, $headline);
if($stmt->execute() === false)
{
// an error occurred, do something!
}
while($stmt->fetch())
{
// do something with $id and $headline
}
$stmt->close();
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