Problem with converting number to date

[PUNEETHH2O]

I am taking yyyy,mm,dd from difrent select boxes.
while i concatinate this using following code.
$dob=$doby.$dob m.$dobd; /it gives as yyyymmdd/
but i want it in format yyyy-mm-dd
i have tried this
$dob=implode('-', array($doby, $dobm, $dobd));but it subtracts 3 numbers(ie. 2000-10-10 = 2080)
I want it as 2000-10-10 to insert into DataBase

[Rabbit]

You already know how to concatenate so you just need to concatenate the dash characters.

$dob=$doby.'-'.$dobm.'-'.$dobd;

[Dormilich]

i have tried this
$dob=implode('-', array($doby, $dobm, $dobd)); but it subtracts 3 numbers (ie. 2000-10-10 = 2080)

then you most probably did not use quotes in the query. hence SQL sees an expression and evaluates it. (btw. 2000-10-10 = 1980)