how timestamp's timezone works in a database and/or Laravel

I have a question regarding timezone for timestamps.

How the timezone in app.php is used? I realized that the behavior is different if I create a timestamp using Carbon or if I query the value (timestamp) from the DB.

Note: My MySQL use system's timezone which is GMT+8 or Asia/Kuala_Lumpur.

1. Example #1
   • Set timezone="UTC" in app.php
   • Create a Carbon instance

>>> new Carbon\Carbon;
=> Carbon\Carbon @1572404830 {#3496
     date: 2019-10-30 03:07:10.625282 UTC (+00:00),
   }
>>>

2. Example #2
   • Set timezone="Asia/Kuala_Lumpur" in app.php
   • Create a Carbon instance

>>> new Carbon\Carbon;
=> Carbon\Carbon @1572404816 {#3520
     date: 2019-10-30 11:06:56.316851 Asia/Kuala_Lumpur (+08:00),
   }

For example #1 and #2, this is for me, expected. You got different value based on the timezone. Things got a little weirder (at least for me), when we query a timestamp from the DB.

3. Example #3
   • Set timezone="UTC" in app.php
   • Query from DB

>>> RefCyberCity::whereDataSource('ccms')->take(1)->first()->updated_at
=> Illuminate\Support\Carbon @1572083605 {#3531
     date: 2019-10-26 09:53:25.0 UTC (+00:00),
   }

4. Example #4
   • Set timezone="Asia/Kuala_Lumpur" in app.php
   • Query from DB

>>> RefCyberCity::whereDataSource('ccms')->take(1)->first()->updated_at
[!] Aliasing 'RefCyberCity' to 'App\RefCyberCity' for this Tinker session.
=> Illuminate\Support\Carbon @1572054805 {#3491
     date: 2019-10-26 09:53:25.0 Asia/Kuala_Lumpur (+08:00),
   }

We can see that both output 2019-10-26 09:53:25.0 but the timezone is different.

via Chebli Mohamed