php - 将 MySQL 查询限制为偶数个结果

Question

我有一些 PHP 代码需要从 MySQL 数据库返回偶数个结果。我正在使用 mysqli 扩展来执行我的查询。

目前我的代码大概是这样的:

//assume we already have a database connection

$query = "SELECT id 
            FROM movies 
           WHERE publish = 1
             AND showimage = 1
        ORDER BY date DESC
           LIMIT 6";

$result = $connection->query($query);

while ($row = $result->fetch_assoc()) {
    //do some stuff
}

如您所见，我将查询限制为 6 行，但在某些情况下，返回的行会更少。如果只返回 3 行，我想扔掉最后一行，只保留 2 行。

如何在 MySQL 查询或 MySQLi 中执行此操作？

Answer 1

我会想象这样的事情:

// row counter
$counter = 1;
// loop through each row
while($row = $result->fetch_assoc()) {
    // If there is more than one row remaining 
    // OR if the current row can be divided by two
    if (($result->num_rows - $counter) > 1 || ($counter % 2)) {
        // result code for even rows
        $counter++;
    } else {
        // break out of the loop
        break;
    }
}