为什么我不能在PHP中更改日期格式

Question

I'm facing problem with date format in PHP because I can't change time format I want to get this format 2015-12-07 13:46:58 am

This is timezone

date_default_timezone_set("Asia/Phnom_Penh");
date_default_timezone_get();

To echo times out

echo date("Y-m-d H:i:s a");
echo date("Y-m-d G:i:s a");

Result

2015-12-07 1:46:58 am

2015-12-07 1:46:58 am

They are the same and

Answer 1

The Format letter H or G is conflicting with a .

H is for a 24 hours clock, which isn't applicable to am/pm suffix

G is for a 12 hours clock, but it's 13:46 which is actually 1:46 am

Bottom line: the a rules.