php - 使用php从数据库中获取后如何比较日期和时间？

Question

假设我让这段代码在一个循环中运行，其中 $fid 将在每一轮接收一个值:

     $result2 = mysql_query( "SELECT date_create FROM users WHERE id = $fid");

现在，date_create 将采用以下格式

2012-08-16 20:13:49

我的问题是，如何检查该日期是否早于 2012-08-31，例如 2012-08-10？

我的完整代码，以防万一有人问起。

$query = "(SELECT distinct fid FROM coin WHERE uid = 59  )";
$result = mysql_query($query);
while($rows = mysql_fetch_array($result))
{
    $fid = $rows['fid'];
    echo 'fid || '.$fid;
    $result2 = mysql_query( "SELECT id, date_create FROM users WHERE id = $fid");
     $rows2 = mysql_fetch_array($result2);

     echo "  ||   users id : " . $rows2['id']; 

     if( $rows2['date_create'] < "2012-8-31") // How do i get something like this? 
     {

          echo "  ||   date_create : " . $rows2['date_create'] ." True"; 

     }
     else
     {
           echo "  ||   date_create : " . $rows2['date_create'] . "False"; 
     }  
    l();
}

到目前为止我得到的结果是这样的:

fid || 1112 || users id : 1112 || date_create : 2012-08-16 20:13:49 false <--
fid || 1113 || users id : 1113 || date_create : 2012-08-16 20:14:11 false <--
fid || 1115 || users id : 1115 || date_create : 2012-08-16 20:14:21 false <--
fid || 1117 || users id : 1117 || date_create : 2012-08-16 20:14:38 false <--
fid || 1118 || users id : 1118 || date_create : 2012-08-16 20:15:03 false <--
fid || 1119 || users id : 1119 || date_create : 2012-08-16 20:15:10 false <-- 

n.b 如果您也能提供一种检查时间的方法，我们将不胜感激。这将是额外的 :D

Answer 1

您可以通过转换日期/时间字符串并使用 strtotime() 进行比较来完成此操作.使用该方法，您还可以调整它以比较秒数:

//this effectively checks to see that the time is greater than '2012-08-16 20:13:49'
//the total calculated time on the RHS of the >= operator is effectively '2012-08-16 20:13:49'
//hence, this will echo 'YES'

//this is of the form: hours, minutes, seconds
$time_difference = (44 * 60 * 60) + (13 * 60) + 49;

if (strtotime('2012-08-16 20:13:49') >= strtotime('2012-08-15') + $time_difference)
{
  echo 'YEAH';
}
else
{
  echo 'NO';
}

更新:

来自 strtotime() 上的 PHP 文档:

The valid range of a timestamp is typically from Fri, 13 Dec 1901 20:45:54 UTC to Tue, 19 Jan 2038 03:14:07 UTC. (These are the dates that correspond to the minimum and maximum values for a 32-bit signed integer.) Additionally, not all platforms support negative timestamps, therefore your date range may be limited to no earlier than the Unix epoch. This means that e.g. dates prior to Jan 1, 1970 will not work on Windows, some Linux distributions, and a few other operating systems. PHP 5.1.0 and newer versions overcome this limitation though.

For 64-bit versions of PHP, the valid range of a timestamp is effectively infinite, as 64 bits can represent approximately 293 billion years in either direction.