获取连续签到起始日期

 根据用户信息及签到日期，获取用户起始的签到天数，可以根据当天是否签到获取连签天数

$signinTables = getAllSignTable();
// 当前月表
$curTable = 'signinlog'.date('Ym');
$signStartDate = '';
foreach ($signinTables as $table) {
    // 应签天数
    $needDays = $curTable == $table ? ((int)date('d') -1) : (int)date('t');
    $monthFirstDay = date('Y-m-01',strtotime(substr($table,6).'01'));
    $endDay = $curTable == $table ? date('Y-m-d',strtotime('-1 day')) : date('Y-m-t',strtotime($monthFirstDay));
    // 该月累计签到天数
    $sql = " select signdate from {$table} where userid={$userid}";
    $result = $actDb->getAll($sql);
    if ($needDays > count($result)) {
        if (empty($result)) {
            break;
        }
        $signDayArr = array_column($result,'signdate');
        for($i = $endDay; $i >= $monthFirstDay; $i = date('Y-m-d',strtotime('-1 day',strtotime($i)))) {
            if (!in_array($i,$signDayArr)) {
                break 2;
            }
            $signStartDate = $i;
        }
    } else {
        $signStartDate = date('Y-m-d',strtotime(substr($table,6).'01'));
    }
}
echo $signStartDate;