how to get date difference in mysql code example

Example 1: mysql date between two dates

ex1:
SELECT * FROM `objects` 
WHERE  (date_field BETWEEN '2010-01-30 14:15:55' AND '2010-09-29 10:15:55')

ex2:
WHERE 
   requireddate BETWEEN 
     CAST('2003-01-01' AS DATE) AND 
     CAST('2003-01-31' AS DATE);

Example 2: mysql date between two dates

-- With implicit CAST
SELECT * FROM my_table 
	WHERE my_date BETWEEN '2021-06-01 01:12:00' AND '2021-06-30 23:59:59';
-- is EQUIVALENT to
SELECT * FROM my_table 
	WHERE my_date >= '2021-06-01 01:12:00' AND my_col <= '2021-06-30 23:59:59';