Current quarter and four future quarters

Question

Hello Forum Members,
I have a config table with the following data:
Quarter Config Rep_date
Q1-2006|1|1/1/2006
Q2-2006|32|4/12/2006
Q3-2006|321|7/15/2006
Q4-2006|897|12/14/2006
Q1-2007|10|2/12/2007
Q2-2007|10|5/12/2007
Q4-2007|50|11/12/2007
Q1-2008|30|1/1/2008
Q2-2008|57|4/10/2008
Q4-2008|45|12/12/2008
Q3-2008|34|8/8/2008
Q4-2005|21|12/1/2005
Q3-2005|20|8/22/2005
Q2-2005|65|4/14/2005
Q1-2005|65|1/14/2005
Q3-2007|435|9/9/2007
I have to show current quarter and four future quarters in oracle form.
ie
Q4-2007|50|
Q1-2008|30|
Q2-2008|57|
Q3-2008|34|
Q4-2008|45|
Please advise me.
Thanks

Answer 1

Coming at it from a different angle, you could fix the data before doing the query. This makes the query much simpler, which is good if it has to be used in many places in the application. Obviously the best way would be to make the quarter column a date column, but that's not always possible. A view or a function-based index can do the same job:
DROP TABLE quarters;
CREATE TABLE quarters AS
SELECT a quarter, b config, To_Date(c,'MM/DD/YYYY') rep_date FROM(
  SELECT 'Q1-2006' a, 1 b, '1/1/2006' c FROM dual UNION ALL
  SELECT 'Q2-2006', 32, '4/12/2006' FROM dual UNION ALL
  SELECT 'Q3-2006', 321, '7/15/2006' FROM dual UNION ALL
  SELECT 'Q4-2006', 897, '12/14/2006' FROM dual UNION ALL
  SELECT 'Q1-2007', 10, '2/12/2007' FROM dual UNION ALL
  SELECT 'Q2-2007', 10, '5/12/2007' FROM dual UNION ALL
  SELECT 'Q4-2007', 50, '11/12/2007' FROM dual UNION ALL
  SELECT 'Q1-2008', 30, '1/1/2008' FROM dual UNION ALL
  SELECT 'Q2-2008', 57, '4/10/2008' FROM dual UNION ALL
  SELECT 'Q4-2008', 45, '12/12/2008' FROM dual UNION ALL
  SELECT 'Q3-2008', 34, '8/8/2008' FROM dual UNION ALL
  SELECT 'Q4-2005', 21, '12/1/2005' FROM dual UNION ALL
  SELECT 'Q3-2005', 20, '8/22/2005' FROM dual UNION ALL
  SELECT 'Q2-2005', 65, '4/14/2005' FROM dual UNION ALL
  SELECT 'Q1-2005', 65, '1/14/2005' FROM dual UNION ALL
  SELECT 'Q3-2007', 435, '9/9/2007' FROM dual
CREATE OR REPLACE FUNCTION get_qtr_date(p IN VARCHAR2) RETURN DATE DETERMINISTIC AS
BEGIN
  RETURN Add_Months(Trunc(To_Date(SubStr(p,4),'YYYY'),'YYYY'), (To_Number(SubStr(p,2,1))-1)*3);
END;
CREATE INDEX function_based ON quarters(get_qtr_date(quarter));
SELECT * FROM quarters
WHERE get_qtr_date(quarter) BETWEEN Trunc(SYSDATE-100,'Q') AND Add_Months(Trunc(SYSDATE-100,'Q'), 12)
ORDER BY get_qtr_date(quarter);
QUARTER CONFIG REP_DATE
Q3-2007    435 09-SEP-07
Q4-2007     50 12-NOV-07
Q1-2008     30 01-JAN-08
Q2-2008     57 10-APR-08
Q3-2008     34 08-AUG-08Another benefit of a function-based index on a column which has to take a specific format is that you can validate the data on the way in rather than checking it on the way out. For example:
CREATE OR REPLACE FUNCTION get_qtr_date(p IN VARCHAR2) RETURN DATE DETERMINISTIC AS
BEGIN
  IF InStr(p,'Q') != 1 THEN
    Raise_Application_Error(-20000, 'Invalid quarter format');
  END IF;
  RETURN Add_Months(Trunc(To_Date(SubStr(p,4),'YYYY'),'YYYY'), (To_Number(SubStr(p,2,1))-1)*3);
END;
INSERT INTO quarters VALUES('P3-2009',100,To_Date('10/10/2009','DD/MM/YYYY'));
ORA-20000: Invalid quarter format
ORA-06512: at "TEST.GET_QTR_DATE", line 4