How to convert MySQL time to UNIX timestamp using PHP?

Use strtotime(..):

$timestamp = strtotime($mysqltime);
echo date("Y-m-d H:i:s", $timestamp);

Also check this out (to do it in MySQL way.)

http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_unix-timestamp

You can mysql's UNIX_TIMESTAMP function directly from your query, here is an example:

SELECT UNIX_TIMESTAMP('2007-11-30 10:30:19');

Similarly, you can pass in the date/datetime field:

SELECT UNIX_TIMESTAMP(yourField);

From one of my other posts, getting a unixtimestamp:

$unixTimestamp = time();

Converting to mysql datetime format:

$mysqlTimestamp = date("Y-m-d H:i:s", $unixTimestamp);

Getting some mysql timestamp:

$mysqlTimestamp = '2013-01-10 12:13:37';

Converting it to a unixtimestamp:

$unixTimestamp = strtotime('2010-05-17 19:13:37');

...comparing it with one or a range of times, to see if the user entered a realistic time:

if($unixTimestamp > strtotime("1999-12-15") && $unixTimestamp < strtotime("2025-12-15"))
{...}

Unix timestamps are safer too. You can do the following to check if a url passed variable is valid, before checking (for example) the previous range check:

if(ctype_digit($_GET["UpdateTimestamp"]))
{...}