php 如何在php/mysql中比较日期和时间
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how to compare date and time in php/ mysql
提问by Princewill Obinna Iwuorie
i need to compare date and time in php/mysql basically i have an application and a server the application needs to connect to the server to check new entries into the database. the server receives the datetime as a string from the application which is done here
我需要在 php/mysql 中比较日期和时间，基本上我有一个应用程序和一个服务器，该应用程序需要连接到服务器以检查数据库中的新条目。服务器从此处完成的应用程序接收日期时间作为字符串
SimpleDateFormat dateformat = new SimpleDateFormat("yyyy/mm/dd hh:mm:ss");
Calendar cal = Calendar.getInstance();
String time = dateformat.format(cal.getTime());
the server receives the data here
服务器在这里接收数据
f (isset($_GET["time"]) || isset($_GET["user_id"])) {
$time = $_GET['time'];
$u_id = $_GET['user_id'];
$timestr=date('y-m-d H:i:s',strtotime($time));
$result = mysql_query("SELECT MAX(created_at)from room");
$Max_time = mysql_result($result, $row);
$dbMax_time = date('y-m-d H:i:s',strtotime($Max_time));
and the comparison needs to be done here
并且需要在这里进行比较
if ($dbMax_time> $timestr) {
$NewRooms = mysql_query("SELECT * From room WHERE created_at> CAST($timestr AS TIME)");
}
how do i go about this am confused on how to compare please help me to FIX it.
我该如何解决这个问题，我对如何比较感到困惑，请帮助我修复它。
回答by Smar
Just comparing two timestamps would suffice:
只需比较两个时间戳就足够了：
$t1 = strtotime($time);
$t2 = strtotime($Max_Time);
if($t1 > $t2) { .. }
回答by Benz
Why don't you create two DateTime objects and compare these?
为什么不创建两个 DateTime 对象并比较它们？
Like:
喜欢：
$A = new DateTime();
$A->setTimestamp(strtotime($time));
$B = new DateTime();
$B->setTimestamp(strtotime($Max_Time));
if ($A > $B) echo "You use if statements to compare"
