Convert from varchar to datetime and compare in MySQL?

For this, you can use STR_TO_DATE(). Let us first create a table −

mysql> create table DemoTable1565
   -> (
   -> ArrivalDatetime varchar(40)
   -> );
Query OK, 0 rows affected (0.82 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1565 values('10/01/2019 21:29:35');
Query OK, 1 row affected (0.22 sec)
mysql> insert into DemoTable1565 values('10/13/2019 4:56:00');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable1565 values('10/13/2018 12:40:46');
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable1565 values('10/13/2019 21:30:00');
Query OK, 1 row affected (0.58 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1565;

This will produce the following output −

+---------------------+
| ArrivalDatetime     |
+---------------------+
| 10/01/2019 21:29:35 |
| 10/13/2019 4:56:00  |
| 10/13/2018 12:40:46 |
| 10/13/2019 21:30:00 |
+---------------------+
4 rows in set (0.00 sec)

The current date is as follows −

mysql> select now();
+---------------------+
| now()               |
+---------------------+
| 2019-10-13 21:34:14 |
+---------------------+
1 row in set (0.00 sec)

Here is the query to convert from varchar to datetime and compare −

mysql> select * from DemoTable1565 where str_to_date(ArrivalDatetime,'%m/%d/%Y')=curdate();

This will produce the following output −

+---------------------+
| ArrivalDatetime     |
+---------------------+
| 10/13/2019 4:56:00  |
| 10/13/2019 21:30:00 |
+---------------------+
2 rows in set, 4 warnings (0.03 sec)