【转】php 得到上周，本周，上月，本月，本季度，上季度

转自：http://www.the8m.com/blog/article/phpa/phpwek.html

注意强大的strtotime()函数和mktime()函数。

    <?php   
    echo date("Ymd",strtotime("now")), "\n";   
    echo date("Ymd",strtotime("-1 week Monday")), "\n";   
    echo date("Ymd",strtotime("-1 week Sunday")), "\n";   
    echo date("Ymd",strtotime("+0 week Monday")), "\n";   
    echo date("Ymd",strtotime("+0 week Sunday")), "\n";   
      
    echo "*********第几个月:";   
    echo date('n');    
    echo "*********本周周几:";   
    echo date("w");    
    echo "*********本月天数:";   
    echo date("t");   
    echo "*********";   
      
    echo '<br>上周:<br>';   
    echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m"),date("d")-date("w")+1-7,date("Y"))),"\n";   
    echo date("Y-m-d H:i:s",mktime(23,59,59,date("m"),date("d")-date("w")+7-7,date("Y"))),"\n";   
    echo '<br>本周:<br>';   
    echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m"),date("d")-date("w")+1,date("Y"))),"\n";   
    echo date("Y-m-d H:i:s",mktime(23,59,59,date("m"),date("d")-date("w")+7,date("Y"))),"\n";   
      
    echo '<br>上月:<br>';   
    echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m")-1,1,date("Y"))),"\n";   
    echo date("Y-m-d H:i:s",mktime(23,59,59,date("m") ,0,date("Y"))),"\n";   
    echo '<br>本月:<br>';   
    echo date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m"),1,date("Y"))),"\n";   
    echo date("Y-m-d H:i:s",mktime(23,59,59,date("m"),date("t"),date("Y"))),"\n";   
        
    $season = ceil((date('n'))/3);//当月是第几季度   
    echo '<br>本季度:<br>';   
    echo date('Y-m-d H:i:s', mktime(0, 0, 0,$season*3-3+1,1,date('Y'))),"\n";   
    echo date('Y-m-d H:i:s', mktime(23,59,59,$season*3,date('t',mktime(0, 0 , 0,$season*3,1,date("Y"))),date('Y'))),"\n";   
        
    $season = ceil((date('n'))/3)-1;//上季度是第几季度   
    echo '<br>上季度:<br>';   
    echo date('Y-m-d H:i:s', mktime(0, 0, 0,$season*3-3+1,1,date('Y'))),"\n";   
    echo date('Y-m-d H:i:s', mktime(23,59,59,$season*3,date('t',mktime(0, 0 , 0,$season*3,1,date("Y"))),date('Y'))),"\n";    
    ?>   
        
    php两个日期相减得天数   
    <?php   
    function count_days($a,$b){   
     $a_dt=getdate($a);   
     $b_dt=getdate($b);   
     $a_new=mktime(12,0,0,$a_dt['mon'],$a_dt['mday'],$a_dt['year']);   
     $b_new=mktime(12,0,0,$b_dt['mon'],$b_dt['mday'],$b_dt['year']);   
     return round(abs($a_new-$b_new)/3600/24);   
    }   
        function count_days($formdate,$todate){   
            return round(abs(strtotime($formdate)-strtotime($todate))/3600/24);   
        }