mysqli 准备的问题变量数不匹配

我收到错误"变量数与预准备语句中的参数数不匹配"

 $stmt = $this->conn->prepare( "INSERT INTO  user 
            ( 
                st1, u1, e1, sa1, 
                h1, roles_id, name_titles_id, first_name, 
                last_name, phone,  mobile, address_road,
                address_area, address_region, post_code, city, 
                country_id, creation_date, activated_at, modified_date_time, 
                created_by, referred_by, gender, ad1, status 
            ) 
            VALUES 
            ( 
                ?, ?, ?, ?, 
                ?, ?, ?, ?, 
                ?, ?, ?, ?, 
                ?, ?, ?, ?, 
                ?, ?, ?, ?,
                ?, ?, ?, ?, ?
                 )" 
            ) 

        $stmt->bind_param('i',$st1);
        $stmt->bind_param('s',$u1);
        $stmt->bind_param('s',$e1);
        $stmt->bind_param('s',$sa1);
        $stmt->bind_param('s',$h1);
        $stmt->bind_param('i',$roles_id);
        $stmt->bind_param('i',$name_titles_id);
        $stmt->bind_param('s',$first_name);
        $stmt->bind_param('s',$last_name);
        $stmt->bind_param('s',$phone);
        $stmt->bind_param('s',$mobile);
        $stmt->bind_param('s',$address_road);
        $stmt->bind_param('s',$address_area);
        $stmt->bind_param('s',$address_region);
        $stmt->bind_param('s',$post_code);
        $stmt->bind_param('s',$city);
        $stmt->bind_param('i',$country_id);
        $stmt->bind_param('s',$creation_date);
        $stmt->bind_param('s',$activated_at);
        $stmt->bind_param('s',$modified_date_time);
        $stmt->bind_param('i',$created_by);
        $stmt->bind_param('i',$referred_by);
        $stmt->bind_param('s',$gender);
        $stmt->bind_param('s',$ad1);
        $stmt->bind_param('i',$status);

编辑：

只需做一个小测试，它就会确认，我们不能对 mysqli 使用多个bind_param。

不工作：

$stmt->bind_param('s',$a);
$stmt->bind_param('s',$b); 

工作：

$stmt->bind_param('ss',$a, $b);

希望它对将来的搜索有用。