在php中减去一天的时间方法

Question

I have the following query in some code...

$student_result = db_query("select id,timestamp,time_id,unschedule_code from student where canceled='0' and email='".$email."' and timestamp > '".time()."'");

I want to change and timestamp > '".time()."'"); to time - 1 day. I tryed something like...

$student_result = db_query("select id,timestamp,time_id,unschedule_code from student where canceled='0' and email='".$email."' and timestamp > '".time(). - 1"'");

...with no luck. Page simply fails to load, so I'm sure the syntax is not even valid. Any help appreciated...

Answer 1

Timestamps are in seconds, try:

$student_result = db_query("select id,timestamp,time_id,unschedule_code from student where canceled='0' and email='".$email."' and timestamp > '".(time()-(3600*24))."'");