php - mysql prepared statement "truncate table ?" returns null

Question

in a function to truncate a table I can use

$stmt = $mysqli->prepare("truncate table packed_items");

and $stmt is set to a mysqli_stmt Object, but
if I try

$stmt = $mysqli->prepare("truncate table ?");

then $stmt is set to null and the statment:

$stmt->bind_param("s", $mytable)

will crash with error
Call to a member function bind_param() on a non-object in

I am using parameterized prepared statements to select,insert and update with no problem.

Answer 1

您不能绑定任何 SQL 文字，但只能绑定数据之一。没有关键字，没有运算符，没有标识符。

如果您确实需要动态截断您的表，并且不知道名称（因为随机截断表显然是非常糟糕的设计的标志），请根据白名单检查表名，正确格式化，然后插入查询字符串。