In mysql, how can I update timestamp type?

Hi I have a table which have timestamp value, when I write that in php

mysql_query("UPDATE 开发者_如何学编程table SET date=$newdate WHERE name=ibrahim");

it does not work. $newdate is a string value that I read from same table before. How can I change date column? thanks for help...

You need to put string values (including date literals) in quotes for MySQL.

 mysql_query("UPDATE table SET date='$newdate' WHERE name='ibrahim'")

mysql_query("UPDATE table SET date='{$newdate}' WHERE name='ibrahim'"); //quote your strings