php 得到上周，本周，上月，本月，本季度，上季度

<? 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 );
    }
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