php - SQL 和 PHP 按发布的年、日和月对数据进行分组

Question

我一直在尝试根据发布的年份和月份显示数据库中的帖子，但无法做到这一点，因为我已尽我所能，但仍然认为这可以在 SQL 查询中完成并在 PHP 端支持它。下面是我的数据库结构

id  | title                |  date 
-------------------------------------------------
1   | hello this is a post | 2016-01-03 11:33 AM
2   | this is what i think | 2016-01-03 10:33 PM
3   | this is it           | 2017-14-06 06:33 PM
4   | Blah Blah Blah       | 2017-01-03 10:33 AM
5   | is what i think      | 2016-04-03 10:33 PM

现在我想这样选择和分组

Your post on 2016-01-03

hello this is a post

this is what i think Your

post on 2017-14-06

this is it

Your post on 2017-01-03

Blah Blah Blah

Your post on 2017-01-03

is what i think

我试着用下面的代码来做这个

<?php
//I swear i don't know what else to do here
$db->prepare('SELECT * FROM post 
GROUP BY ("")
ORDER BY date');
$db->execute();
$output = $db->getAll();
$db->free();
if(!is_null($output)){
foreach($output as $row){
$title = $row->title;
$date = $row->date;

/* 
 Only this path i got near but i can only display post for this month using   $currentDate below.
But how can i get other once split according to date?
*/

$split = explode(" ", $date);
$currentDate = date('Y-m-d');
if($split[0] == $currentDate){
  echo 'post on '.$currentDate.'<br/>'.$title;
}else{
   echo 'post on '.$split[0].'<br/>'.$title;
 }
?>

Answer 1

您在这里有三个要求。一种是在没有时间的情况下呈现帖子的日期。第二种是按日期/时间对帖子进行排序。

这些可以通过这样的查询来完成。

SELECT DATE(`date`) as date, `title` FROM post ORDER BY `date`

GROUP BY 对此没有任何作用。

第三个要求是，当连续发布的日期相同时，只呈现一次日期。这必须在 php 中完成。

$prev_date = "";
foreach ($output as $row) {
    $title = $row->title;
    $date = $row->date;
    if ($date != $prev_date) {
        echo "Posts on " .$date;
    }
    echo information about the post
    $prev_date = $date;
}

诀窍是使用我命名为 $prev_date 的变量来检测日期何时从一行到另一行发生变化。