PHP MySQL insert date

Answer: 
MySQL recognizes DATE values in these formats:

As a string in either 'YYYY-MM-DD' or 'YY-MM-DD' format. A “relaxed” syntax is permitted: Any punctuation character may be used as the delimiter between date parts. For example, '2012-12-31', '2012/12/31', '2012^12^31', and '2012@12@31' are equivalent.

As a string with no delimiters in either 'YYYYMMDD' or 'YYMMDD' format, provided that the string makes sense as a date. For example, '20070523' and '070523' are interpreted as '2007-05-23', but '071332' is illegal (it has nonsensical month and day parts) and becomes '0000-00-00'.

As a number in either YYYYMMDD or YYMMDD format, provided that the number makes sense as a date. For example, 19830905 and 830905 are interpreted as '1983-09-05'.

Therefore, the string '08/25/2012' is not a valid MySQL date literal. You have four options (in some vague order of preference, without any further information of your requirements):

Configure Datepicker to provide dates in a supported format using its dateFormat option:

$( ".selector" ).datepicker({ dateFormat: "yyyy-mm-dd" });
Use MySQL's STR_TO_DATE() function to convert the string:

INSERT INTO user_date VALUES ('', '$name', STR_TO_DATE('$date', '%m/%d/%Y'))
Convert the string received from jQuery into a PHP timestamp—e.g. using strtotime():

$timestamp = strtotime($_POST['_date']);
and then either:

format the timestamp using date():

$date = date('Y-m-d', $timestamp);
pass the timestamp directly to MySQL using FROM_UNIXTIME():

INSERT INTO user_date VALUES ('', '$name', FROM_UNIXTIME($timestamp))
Manually manipulate the string into a valid literal:

$parts = explode('/', $_POST['date']);
$date = "$parts[2]-$parts[0]-$parts[1]";