BETWEEN and standard comparison operators Oracle SQL - sql

Question

As I need range of data I am using BETWEEN because, as far as I know, this two queries below should be same:
select * from table1 where my_date1 - my_date2 between (-1) and (-30);
and
select * from table1 where my_date1 - my_date2 <= (-1) and my_date1 - my_date2 >= (-30);
However when I try it in my script:
SELECT
a.account_no AS ACCOUNT_NO,
a.installment_no AS INSTALLMENT_NO,
a.INSTALLMENT_DATE AS INSTALLMENT_DATE
FROM myTable a
INNER JOIN (SELECT
ACCOUNT_NO,
MIN(INSTALLMENT_NO) AS INSTALLMENT_NO
FROM myTable
WHERE
ACCOUNT_NO IS NOT NULL
AND INSTALLMENT_NO IS NOT NULL
AND STATUS = 'A'
GROUP BY ACCOUNT_NO) b
ON A.ACCOUNT_NO = B.ACCOUNT_NO AND A.INSTALLMENT_NO = B.INSTALLMENT_NO
WHERE (TRUNC(INSTALLMENT_DATE) - TRUNC(TO_DATE('12/01/2011','DD/MM/YYYY'))) BETWEEN (-1) AND (-30) -- If I change this
I got 0 rows, But when I change
WHERE (TRUNC(INSTALLMENT_DATE) - TRUNC(TO_DATE('12/01/2011','DD/MM/YYYY'))) BETWEEN (-1) AND (-30)
to
WHERE (TRUNC(INSTALLMENT_DATE) - TRUNC(TO_DATE('12/01/2011','DD/MM/YYYY'))) <= (-1) and (TRUNC(INSTALLMENT_DATE) - TRUNC(TO_DATE('12/01/2011','DD/MM/YYYY'))) >= (-30)
I get more than 0 rows. I would like to use BETWEEN as it is more readable. Am I missing something?

Answer 1

I believe the syntax for the range used with BETWEEN is:
WHERE col BETWEEN <smaller_value> AND <larger_value>
which is equivalent to
WHERE col >= <smaller_value> AND col <= <larger_value>
Your current WHERE clause is looking for date a date difference greater than -1 and less than -30. This will eliminate all the records you are trying to target, and in fact will never be true. To fix this, correct the range:
WHERE (TRUNC(INSTALLMENT_DATE) - TRUNC(TO_DATE('12/01/2011','DD/MM/YYYY')))
BETWEEN (-30) AND (-1)

Answer 2

https://docs.oracle.com/cd/B28359_01/server.111/b28286/conditions011.htm#SQLRF52147 says:
expr1 [NOT] BETWEEN expr2 AND expr3
If expr3 < expr2, then the interval is empty.

Answer 3

BETWEEN is a syntax shortcut that is evaluated as
WHERE col >= [smaller_value] AND <= [larger_value]
and it is VITAL that the values compared to are presented in that order (small then large) otherwise it will never be satisfied.
HOWEVER I never recommend using between for date ranges and suggest, instead, that one always uses this syntax instead:
WHERE col >= [smaller_value] AND < [larger_value]+1
This syntax allows accurate filtering of date/time information for any level of time precision.