我显示此错误从字符串转换datetime时转换失败

Question

我想保存数据网格视图中的字段数，然后存储在数据库中。

$query = "INSERT INTO users (Fuid, Ffname)   
VALUES (?, ?)   
ON DUPLICATE KEY UPDATE users   
 SET Ffname = ?"; 

if(!$stmt = $db->prepare($query)){ 
    // prepare failed 
    printf("Prepare failed: %s<br>Error: %s.<br>", $query, $db->error); 
} else { 
    // prepare worked 
    $stmt->bind_param('iss',$fuid,$ffname,$ffname); 
    if(!$stmt->execute()){ 
        // execute failed 
        printf("Execute failed: %s<br>Error: %s.<br>", $query, $stmt->error); 
    } else { 
        // execute worked 

        // any code dependent on the insert query running would go here... 

    } 
}  

它向我显示了这个错误：

  

从字符串转换日期时转换失败。