Get the time difference and convert it to hours in MySQL?

You can achieve with the help of timestampdiff() method from MySQL. The syntax is as follows −

Syntax

SELECT ABS(TIMESTAMPDIFF(HOUR,yourColumnName1,yourColumnName2)) as
anyVariableName from yourTableName;

To understand the above syntax, let us create a table. The query to create a table is as follows −

mysql> create table DifferenceInHours
   -> (
   -> StartDateTime datetime,
   -> EndDateTime datetime
   -> );
Query OK, 0 rows affected (0.59 sec)

Insert some records in the table using insert command. The query is as follows −

mysql> insert into DifferenceInHours values('2018-12-20 10:00:00', '2018-12-19 12:00:00');
Query OK, 1 row affected (0.11 sec)

mysql> insert into DifferenceInHours values('2018-12-20 11:00:00', '2018-12-19 11:00:00');
Query OK, 1 row affected (0.16 sec)

mysql> insert into DifferenceInHours values('2018-12-20 10:30:00', '2018-12-19 11:00:00');
Query OK, 1 row affected (0.13 sec)

Display all records from the table using select statement. The query is as follows −

mysql> select *from DifferenceInHours;

Output

+---------------------+---------------------+
| StartDateTime       | EndDateTime         |
+---------------------+---------------------+
| 2018-12-20 10:00:00 | 2018-12-19 12:00:00 |
| 2018-12-20 11:00:00 | 2018-12-19 11:00:00 |
| 2018-12-20 10:30:00 | 2018-12-19 11:00:00 |
+---------------------+---------------------+
3 rows in set (0.00 sec)

Here is the query that gets time difference in hours. The query is as follows −

mysql> SELECT ABS(TIMESTAMPDIFF(HOUR,StartDateTime,EndDateTime)) as Hour from
DifferenceInHours;

The following is the output displaying the time difference in hours −

+------+
| Hour |
+------+
|   22 |
|   24 |
|   23 |
+------+
3 rows in set (0.00 sec)