Practice Using SQL DATE Functions + DUAL Table

DUAL Table #

It is a virtual table provided by SQL.

You can get the current time as shown below.

SELECT SYSDATE FROM DUAL;

To get n months after or before the current time:

SELECT ADD_MONTHS(SYSDATE, 3) FROM DUAL; # 3 months after
SELECT ADD_MONTHS(SYSDATE, -3) FROM DUAL; # 3 months before

How to get only the year, excluding the time

SELECT TRUNC(SYSDATE) FROM DUAL;

Output DATE in the specified format using TO_CHAR

SELECT TO_CHAR(SYSDATE, 'YYYY-MM-DD HH24:MI:SS') FROM DUAL