如何将 pdo 的准备好的语句用于 order by 和 limit 子句?

2021-12-26 00:00:00 php pdo prepared-statement

我想使用一个准备好的语句，其中传入的参数用于 ORDER BY 和 LIMIT 子句，如下所示:

I want to use a prepared statement in which the passed-in parameters are for the ORDER BY and LIMIT clauses, like so:

$sql = 'SELECT * FROM table ORDER BY :sort :dir LIMIT :start, :results';
$stmt = $dbh->prepare($sql);
$stmt->execute(array(
     'sort'  => $_GET['sort'], 
     'dir'  => $_GET['dir'], 
     'start'  => $_GET['start'],
     'results' => $_GET['results'],
     )
    );

但是 $stmt->fetchAll(PDO::FETCH_ASSOC); 什么都不返回.

But $stmt->fetchAll(PDO::FETCH_ASSOC); returns nothing.

有人能指出我做错了什么吗?可以做到吗?如果没有，我应该参考哪些可以使用参数的子句的完整列表?

Can someone point out what's the wrong thing I am doing? Can it be done? If not,what should I reference for a complete list of clauses where parameters can be used?

推荐答案

使用后:

$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

我收到了消息:

未捕获的异常 'PDOException' 与消息SQLSTATE[42000]:语法错误或访问冲突:1064 你有一个SQL 语法错误；检查与您的 MySQL 相对应的手册正确语法的服务器版本在第 1 行的0"、10"附近使用

Uncaught exception 'PDOException' with message 'SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''0', '10'' at line 1

因此，当您使用数组进行执行时，它会将您的输入视为字符串，这对于 LIMIT 来说不是一个好主意

So, when you use an array for execute, it consider your inputs as string which is not a good idea for LIMIT 

$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$sql = "SELECT * FROM table ORDER BY :sort :dir LIMIT :start, :results";
$stmt = $dbh->prepare($sql);
$stmt->bindParam(':start', $_GET['start'], PDO::PARAM_INT);
$stmt->bindParam(':results', $_GET['results'], PDO::PARAM_INT);
$stmt->bindParam(':sort', $_GET['sort']);
$stmt->bindParam(':dir', $_GET['dir']);
$stmt->execute();

$data = $stmt->fetchAll(PDO::FETCH_ASSOC);
print_r($data);

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