Here are all formats
Say this is the column that contains the datetime value, table data.
+--------------------+
| date_created       |
+--------------------+
| 2018-06-02 15:50:30|
+--------------------+
mysql> select DATE(date_created) from data;
+--------------------+
| DATE(date_created) |
+--------------------+
| 2018-06-02         |
+--------------------+
mysql> select YEAR(date_created) from data;
+--------------------+
| YEAR(date_created) |
+--------------------+
|               2018 |
+--------------------+
mysql> select MONTH(date_created) from data;
+---------------------+
| MONTH(date_created) |
+---------------------+
|                   6 |
+---------------------+
mysql> select DAY(date_created) from data;
+-------------------+
| DAY(date_created) |
+-------------------+
|                 2 |
+-------------------+
mysql> select HOUR(date_created) from data;
+--------------------+
| HOUR(date_created) |
+--------------------+
|                 15 |
+--------------------+
mysql> select MINUTE(date_created) from data;
+----------------------+
| MINUTE(date_created) |
+----------------------+
|                   50 |
+----------------------+
mysql> select SECOND(date_created) from data;
+----------------------+
| SECOND(date_created) |
+----------------------+
|                   31 |
+----------------------+