在foreach循环中分组日期

Question

我想添加一个新行,以便在foreach循环中对日期进行分组.

例:

2015-11-05
2015-11-05

2015-11-07

2015-11-10
2015-11-10
2015-11-10

... and so on

由于我不知道如何实现这一点,因为在谷歌搜索几天后我没有找到任何内容,我只有标准代码foreach来循环数据库中的数据.

SELECT * FROM table ORDER BY datetime_published

foreach($rows AS $row) {
    echo $row['datetime_published'].'<br>';
}

上面的代码打印日期如下:

2015-11-05
2015-11-05
2015-11-07
2015-11-10
2015-11-10
2015-11-10
... and so on

如示例所示,我如何实现这一目标？

数据库结构

`id` int(11) NOT NULL AUTO_INCREMENT,
`id_visitor` int(11) NOT NULL,
`id_place` int(11) NOT NULL,
`id_post` int(11) NOT NULL,
`id_category` int(11) NOT NULL,
`data_cover` varchar(50) COLLATE utf32_swedish_ci NOT NULL,
`data_subject` varchar(45) COLLATE utf32_swedish_ci NOT NULL,
`data_content` text COLLATE utf32_swedish_ci NOT NULL,
`datetime_published` datetime NOT NULL,
`datetime_edited` datetime NOT NULL,
`datetime_saved` datetime NOT NULL

Answer 1

一种方法是保存以前的值并将其与当前值进行比较:

$prev = NULL;
foreach($rows AS $row) {
    $curr = $row['datetime_published'];
    echo "$curr<br>";
    if ($curr != $prev) {
        echo '<br>';
        $prev = $curr;
    }
}