Question

它有效，但我觉得这不是解决我问题的最佳方法。我希望我的代码做的是检查location = 1并发送所有位置的消息。

function getCurrentMessage($location){
    $conn = Connection::getConnection();

    if($location == 1) {
        $query = "SELECT first_name, last_name, description, title, message ,font_size , effective_date 
                FROM tbl_messages
                JOIN tbl_authors ON tbl_authors.id_author = tbl_messages.id_author 
                JOIN tbl_locations ON tbl_messages.id_location = tbl_locations.id_location
                AND effective_date <= CURDATE()
                ORDER BY effective_date desc
                LIMIT 2;";

        $result = array();

        if ($stmt = $conn->prepare($query)) {
            $stmt->bind_result($first_name, $last_name, $location, $title, $message, $size, $date);
            $stmt->execute();

            while ($stmt->fetch()) {
                $message = new Message($first_name, $last_name, $location, $title, $message, $size, $date);
                array_push($result, $message);
            }
        }
    }
    else{
        $query = "SELECT first_name, last_name, description, title, message ,font_size , effective_date 
                FROM tbl_messages
                JOIN tbl_authors ON tbl_authors.id_author = tbl_messages.id_author 
                JOIN tbl_locations ON tbl_messages.id_location = tbl_locations.id_location
                WHERE tbl_messages.id_location = ?
                AND effective_date <= CURDATE()
                ORDER BY effective_date desc
                LIMIT 2;";

        $result = array();

        if ($stmt = $conn->prepare($query)) {
            $stmt->bind_result($first_name, $last_name, $location, $title, $message, $size, $date);
            $stmt->bind_param('i', $location);
            $stmt->execute();

            while ($stmt->fetch()) {
                $m = new Message($first_name, $last_name, $location, $title, $message, $size, $date);
                array_push($result, $m);
            }
        }
    }

    return $result;
}

也许我可以在SQL语句中加入一些逻辑。如果您有任何见解，请帮助。

Answer 1

只需重构所有不依赖于条件的重复部分。

function getCurrentMessage($location){
    $conn = Connection::getConnection();

    if($location == 1) {
        $query = "SELECT first_name, last_name, description, title, message ,font_size , effective_date 
                FROM tbl_messages
                JOIN tbl_authors ON tbl_authors.id_author = tbl_messages.id_author 
                JOIN tbl_locations ON tbl_messages.id_location = tbl_locations.id_location
                AND effective_date <= CURDATE()
                ORDER BY effective_date desc
                LIMIT 2;";

        if (!$stmt = $conn->prepare($query)) {
            return false;
        }

    }
    else{
        $query = "SELECT first_name, last_name, description, title, message ,font_size , effective_date 
                FROM tbl_messages
                JOIN tbl_authors ON tbl_authors.id_author = tbl_messages.id_author 
                JOIN tbl_locations ON tbl_messages.id_location = tbl_locations.id_location
                WHERE tbl_messages.id_location = ?
                AND effective_date <= CURDATE()
                ORDER BY effective_date desc
                LIMIT 2;";

        if (!$stmt = $conn->prepare($query)) {
            return false;
        }
        $stmt->bind_param('i', $location);
    }

    $result = array();

    $stmt->bind_result($first_name, $last_name, $location, $title, $message, $size, $date);
    $stmt->execute();

    while ($stmt->fetch()) {
         $m = new Message($first_name, $last_name, $location, $title, $message, $size, $date);
         array_push($result, $m);
    }

    return $result;
}

你可以走得更远，但这只是一个例子。注意如果语句准备失败，函数如何返回false。由于你在一个函数内部，这将停止执行该函数并返回false，因为如果准备失败则没有进一步的进展。如果你想要一些可以捕获的东西，你也可以使用例外。

Answer 2

我现在意识到这个问题应该已经发布在代码审核中Code review ，但在了解了有关MYSQL的更多信息后，我想出了一种清理代码的方法，所以这是我使用控制流功能的答案如果您有任何其他想法要进一步清理代码，请告诉我。

$conn = getConnection();
$query = "SELECT first_name, last_name, description, title, message ,font_size , DATE_FORMAT(effective_date,'%h:%i %p %m-%d-%Y')
          FROM tbl_messages
          JOIN tbl_authors ON tbl_authors.id_author = tbl_messages.id_author
          JOIN tbl_locations ON tbl_messages.id_location = tbl_locations.id_location
          WHERE tbl_messages.id_location = IF(? = 1,tbl_messages.id_location,?)
          AND effective_date <= NOW()
          ORDER BY effective_date DESC
          LIMIT 1
          ";

if (!$stmt = $conn->prepare($query)) {
    return false;
}

$stmt->bind_param('ii', $location,$location);

$result = array();

$stmt->bind_result($first_name, $last_name, $location, $title, $message, $size, $date);
$stmt->execute();

while ($stmt->fetch()) {
    $m = new Message($first_name, $last_name, $location, $title, $message, $size, $date);
    array_push($result, $m);
}

return $result;

有条件的准备语句PHP mysqli，reduce

2 个答案: