在PHP中有非常好用的时间函数，比如date和strtotime，结合时间戳不仅给数据库设计带来了便利，也让我们更容易的把控对时间的获取。

<?php
date_default_timezone_set('PRC'); //设置中国时区

function getWeekDate($date = '')
{
    $date = empty($date)?date('Y-m-d'):$date;

    $Sunday     = date("Y-m-d",strtotime("$date     Sunday"));
    $Monday     = date("Y-m-d",strtotime("$Sunday - 6 days"));
    $Tuesday    = date("Y-m-d",strtotime("$Sunday - 5 days"));
    $Wednesday  = date("Y-m-d",strtotime("$Sunday - 4 days"));
    $Thursday   = date("Y-m-d",strtotime("$Sunday - 3 days"));
    $Friday     = date("Y-m-d",strtotime("$Sunday - 2 days"));
    $Saturday   = date("Y-m-d",strtotime("$Sunday - 1 days"));
    return [
        '星期一'=>$Monday,
        '星期二'=>$Tuesday,
        '星期三'=>$Wednesday,
        '星期四'=>$Thursday,
        '星期五'=>$Friday,
        '星期六'=>$Saturday,
        '星期天'=>$Sunday
    ];
}

$week = getWeekDate();
foreach ($week as $k => $v){
    echo $k .' => ' .$v.'<br/>';
}

strtotime 官方文档参考；

date  官方文档参考。