MySQL Datetime to add days?

Let us first create a table −

mysql> create table DemoTable1871
     (
     ArrivalDate datetime
     );
Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1871 values('2019-12-19 7:45:00');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1871 values('2018-11-10 12:00:00');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1871 values('2019-01-31');
Query OK, 1 row affected (0.00 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1871;

This will produce the following output −

+---------------------+
| ArrivalDate         |
+---------------------+
| 2019-12-19 07:45:00 |
| 2018-11-10 12:00:00 |
| 2019-01-31 00:00:00 |
+---------------------+
3 rows in set (0.00 sec)

Here is the query to add days −

mysql> update DemoTable1871 set ArrivalDate=date_add(ArrivalDate, interval 6 day);
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3  Changed: 3 Warnings: 0

Let us check table records once again −

mysql> select * from DemoTable1871;

This will produce the following output −

+---------------------+
| ArrivalDate         |
+---------------------+
| 2019-12-25 07:45:00 |
| 2018-11-16 12:00:00 |
| 2019-02-06 00:00:00 |
+---------------------+
3 rows in set (0.00 sec)