-- trunc(date, format)                        DUAL is for Oracle
SELECT trunc(sysdate, 'Q') FROM DUAL;       -- 1rst quarter day
SELECT trunc(sysdate) FROM DUAL;            -- today 00:00:00
SELECT trunc(sysdate, 'YEAR') FROM DUAL;    -- 1rst year day
SELECT trunc(sysdate, 'MONTH') FROM DUAL;   -- 1rst month day