将MySQL查询限制为偶数个结果(使用PHP和mysqli)

Question

我有一些PHP代码,我需要从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.

我的代码目前大约是这样的:

//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,将返回更少的行.如果只返回3行,我想扔掉最后一行,只保留2行.

我如何在MySQL查询或mysli中执行此操作？

提前致谢.

Answer 1

我可能会用PHP而不是SQL来做这件事.在while-loop中,保留一个计数器,当你离开循环时,检查计数器.如果它很奇怪,扔掉最后一次迭代的结果.

Answer 2

我想象这样的事情:

// 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;
    }
}