SQL

oracle first day of last year

-- Oracle: First day of previous year
SELECT trunc(add_months(sysdate, -12), 'YEAR') FROM DUAL;

oracle sql first day of month

-- First day of month
SELECT TRUNC(sysdate, 'MONTH') from dual;

oracle sql first day of year

-- Oracle: First day of year
SELECT TRUNC(sysdate, 'YEAR') FROM DUAL;

oracle sql first day of quarter

-- 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