First day, last date of week, last date of month, last date of quarter and last date of year using Oracle date function

Gets First day, last date of week, last date of month, last date of quarter, last date of year using oracle date functions. 

--First day of current week

SELECT TRUNC (SYSDATE, 'Day') first_day_of_current_week

  FROM DUAL;

--First day of next week

SELECT TRUNC (SYSDATE + 7, 'Day') first_day_of_next_week

  FROM DUAL;

--First day of previous week

SELECT TRUNC (SYSDATE - 7, 'Day') first_day_of_previous_week

  FROM DUAL;

--First day of current month

SELECT TRUNC (SYSDATE, 'Month') first_day_of_current_month

  FROM DUAL;

--First day of previous month

SELECT TRUNC (TRUNC (SYSDATE, 'Month') - 1, 'Month') first_day_of_previous_month

  FROM DUAL;

--First day of next month

SELECT TRUNC (LAST_DAY (SYSDATE) + 1, 'Month') first_day_of_next_month

  FROM DUAL;

--First day of current year

SELECT TRUNC (SYSDATE, 'Year') first_day_of_current_year

  FROM DUAL;

--First day of previous year

SELECT TRUNC (TRUNC (SYSDATE, 'Year') - 1, 'Year') first_day_of_previous_year

  FROM DUAL;

--First day of next year

SELECT ADD_MONTHS (TRUNC (SYSDATE, 'Year'), 12) first_day_of_next_year

  FROM DUAL;

-- First Day of Current quater 

SELECT TRUNC (SYSDATE, 'Q') first_day_of_current_quater

  FROM DUAL;

--  First Day of Previous Quarter

SELECT ADD_MONTHS (TRUNC (SYSDATE, 'Q'), -3) first_day_of_previous_quarter

  FROM DUAL;

--  First Day of Next Quarter

SELECT ADD_MONTHS (TRUNC (SYSDATE, 'Q'), 3) first_day_of_next_quarter

  FROM DUAL;

--Last day of current week

SELECT TRUNC (SYSDATE, 'Day') + 6 last_day_of_current_week

  FROM DUAL;

--Last day of next week

SELECT TRUNC (SYSDATE + 7, 'Day') + 6 last_day_of_next_week

  FROM DUAL;

--Last day of previous week

SELECT TRUNC (SYSDATE - 7, 'Day') + 6 last_day_of_previous_week

  FROM DUAL;

--Last day of current month

SELECT LAST_DAY (TRUNC (SYSDATE, 'Month')) last_day_of_current_month

  FROM DUAL;

--Last day of previous month

SELECT LAST_DAY (TRUNC (TRUNC (SYSDATE, 'Month') - 1, 'Month')) last_day_of_previous_month

  FROM DUAL;

--Last day of next month

SELECT LAST_DAY (TRUNC (LAST_DAY (SYSDATE) + 1, 'Month')) last_day_of_next_month

  FROM DUAL;

--Last day of current year

SELECT LAST_DAY (ADD_MONTHS (TRUNC (SYSDATE, 'Year'), 11)) last_day_of_current_year

  FROM DUAL;

--Last day of previous year

SELECT LAST_DAY (ADD_MONTHS (TRUNC (TRUNC (SYSDATE, 'Year') - 1, 'Year'), 11)) last_day_of_previous_year

  FROM DUAL;

--Last day of next year

SELECT LAST_DAY (ADD_MONTHS (TRUNC (TRUNC (SYSDATE, 'Year') - 1, 'Year'), -13)) last_day_of_next_year

  FROM DUAL;

-- Last Day of Current quater 

SELECT LAST_DAY (ADD_MONTHS (TRUNC (SYSDATE, 'Q'), 2)) last_day_of_current_quater

  FROM DUAL;

--  Last Day of Previous Quarter

SELECT TRUNC (SYSDATE, 'Q') - 1 last_day_of_previous_quarter

  FROM DUAL;

--  Last Day of Next Quarter

SELECT LAST_DAY (ADD_MONTHS (TRUNC (SYSDATE, 'Q'), 5)) last_day_of_next_quarter

  FROM DUAL;

-- Cheers !!!