預設日期+2日 (避開六日) (PHP & DB 作法)

需求: 預設日期為「核准日」+2 (避開週六日) , 這邊提供兩種做法參考: 

PHP Solution1:

// Reference PHP Official Site URL: http://php.net/manual/en/function.date.php 

// date function format about the N , 1 (for Monday) through 7 (for Sunday)

// This function will add working day to a given timestamp

function addworkinday($timestamp,$daystoadd){
    
     $dayoftheweek = date("N",$timestamp);
     $sum =$dayoftheweek +$daystoadd;
    
while ($sum >= 6) {
    
     $daystoadd=$daystoadd+1;
    $sum=$sum-1;
}
return $timestamp +(60*60*24*$daystoadd);

}
?>

My SQL DB Solution1:

// Reference URL: http://stackoverflow.com/questions/1202919/mysql-dayofweek-my-week-begins-with-monday

Describe: 

        Try to use the WEEKDAY() funtion

        Return the weekday index for date  (0 = Monday, 1 = Tuesday, … 6 = Sunday)

也可參閱Mysql官方網站: http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_week

直接查閱出特定日期的 day of week ex: 

Mode	First day of week	Range	Week 1 is the first week …
0	Sunday	0-53	with a Sunday in this year
1	Monday	0-53	with 4 or more days this year
2	Sunday	1-53	with a Sunday in this year
3	Monday	1-53	with 4 or more days this year
4	Sunday	0-53	with 4 or more days this year
5	Monday	0-53	with a Monday in this year
6	Sunday	1-53	with 4 or more days this year
7	Monday	1-53	with a Monday in this year

Example: 

mysql> SELECT WEEK('2008-02-20');

        -> 7

mysql> SELECT WEEK('2008-02-20',0);

        -> 7

mysql> SELECT WEEK('2008-02-20',1);

        -> 8

mysql> SELECT WEEK('2008-12-31',1);

        -> 53

Best Regards & thanks. 

George Huang 烤蕃薯 2016