[英]MySQLi prepared statement issue
我正在(尝试)将查询从未准备好的语句移到MySQLi准备好的语句。 到目前为止,我所学到的应该以以下方式发生:
$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();
$mysqli->close();
如果我回显$ post_id和$ query_blog,我得到正确的结果。 但是当涉及bind_param时,它会卡住。 不知道有什么问题。 任何想法如何运行此?
总的来说,我的代码如下所示:
<?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;
非常感谢!
编辑:如果我准备语句后,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,则会得到以下语句:
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 )
如果我在执行语句后使用print_r,则会得到:
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 )
所以受影响的行更改为-1是否表示没有找到ID = 1的行,因为这肯定在我的数据库中。
编辑2:
如果添加以下语句,我将从查询中获取数据。
$result_blog->bind_result($id, $headline);
$result_blog->fetch();
print_r($headline);
但是如何循环显示结果?
if ($result_blog):
if(mysqli_num_rows($result_blog)>0):
while($blog_entry = mysqli_fetch_assoc($result_blog)):
//Do something
endwhile;
endif;
endif;
这似乎不起作用:-/
一个准备好的语句的简单示例如下所示:
// 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();
对于您的代码,可能看起来像这样:
$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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