绑定Param失败，空变量

Question

$query = "INSERT INTO api_fails (file, code, url, date) VALUES (?, ?, ?, ".time().")";

$stmt = $mysqli->stmt_init();
if(!$stmt->prepare($query)) {
    echo("Failed to prepare statement.<br />\n");
} else {
    $file = $_GET['f'];
    $code = $_GET['c'];
    $url = $_GET['u'];
    $stmt->bind_param("sis", $file, $code, $url);
    if($stmt->execute()) {
        echo("Inserted.<br />\n");
    }else {
        echo("Didn't insert.<br />\n");
    }
}

我发现如果未设置以下任何变量，则插入失败...

    $file = $_GET['f'];
    $code = $_GET['c'];
    $url = $_GET['u'];

如何设置插入，以便在未设置变量的情况下只插入该字段？

Answer 1

如果未设置这些变量，只需将空值分配：

$file = (isset($_GET['f'])) ? $_GET['f'] : '' ;
$code = (isset($_GET['c'])) ? $_GET['c'] : '' ;
$url  = (isset($_GET['u'])) ? $_GET['u'] : '' ;