如何使用php从mysql表中存储的出生日期计算年龄

Question

I have a form with a dynamic select option. I want to calculate the age of a goat in months from its date of birth after selecting it from the db and echo the selected goat age on the following form field that follows the Dynamic selection option. Here is the selection script:

<?php 
$conn = mysqli_connect("localhost", "root", "xxx", "xxxx");
if(mysqli_connect_errno($conn)) {
echo "Unable to connect to database server";
}

$sql = "SELECT * FROM goats WHERE sex='Male'";
$query = mysqli_query($conn, $sql);

echo '<select name="hegoat">';
echo '<option value="">Choose He Goat</option>';
while($hegoats = mysqli_fetch_assoc($query)){
echo "<option>{$hegoats['goatid']}</option>";
}
echo '</select>';
?>

Data Base table is goats with 'dob' as the column for Date of Birth while the form field for age is: <input type="text" name="age" id="age"/>

And my PHP code is

<?php
if(isset($_POST['sub'])) 
{ 
    date_default_timezone_set ("Asia/Calcutta");
    $dateofreg1=date("d M Y");
    $dbd=$_POST['dob'];
    $startTimeStamp = strtotime($dbd);
    $endTimeStamp = strtotime($dateofreg1);
    $timeDiff = abs($endTimeStamp - $startTimeStamp);
    $numberDays = $timeDiff/86400;
    $numberDays = intval($numberDays);
    $days="Total day :".$numberDays;
    $birthDate =$dbd; 
    $birthDate = explode("/", $birthDate);
    $age = (date("md", date("U", mktime(0, 0, 0, $birthDate[0], $birthDate[1], $birthDate[2]))) > date("md") ? ((date("Y") - $birthDate[2]) - 1) : (date("Y") - $birthDate[2]));
    $dobs="Age is:" . $age; 
}
?>

Answer 1

As per your last comment, I am giving this answer.

 <?php if(isset($_POST['sub'])) 
    {
     date_default_timezone_set ("Asia/Calcutta");
    $dateofreg1=date("d M Y");
    $dbd=$_POST['dob'];
    $startTimeStamp = strtotime($dbd);
    $endTimeStamp = strtotime($dateofreg1);

    $year1 = date('Y', $startTimeStamp);   //select year1
    $year2 = date('Y', $endTimeStamp);    //select year 2
    $month1 = date('m', $startTimeStamp);   //month1
    $month2 = date('m', $endTimeStamp);      //month2
    $diff = (($year2 - $year1) * 12) + ($month2 - $month1);  //year*12 and month difference
     $dobs="Age is:" . $diff. "  months";
     ?>

Answer 2

用于计算天数的简单一行代码。

$Days = round(abs(strtotime($dob)-strtotime($currentDate))/86400);