如何从PHP中的日期时间中减去一段时间？

Question

Suppose that I have datetime like 2013-01-16-0900. How can I subtract a length of time - say, 30 minutes?

Answer 1

This will subtract 30 minutes from the supplied timestamp.

echo date( 'Y-m-d-Hi', strtotime( $timestamp ) - 30 * 60 );

$timestamp = '2013-01-16-0900' in this example.