How to run query by quarter

Question

Hi all,
I would like to run this query based on the users selection from the interface. For example if the user select year 2011 and quarter 1, then   this code will be like this                  
                        AND (B.DATELET >= TO_DATE ('2011-01-01', 'YYYY-MM-DD')
                        AND B.DATELET <= TO_DATE ('2011-03-31', 'YYYY-MM-DD'))
When the user select year 2011 and quarter 2 then this code will be like this
                        AND (B.DATELET >= TO_DATE ('2011-04-01', 'YYYY-MM-DD')
                        AND B.DATELET <= TO_DATE ('2011-06-30', 'YYYY-MM-DD'))
Will this possible to change my code here or I need to code this in PL/SQL?  any clue will be appreciated.
SELECT DISTINCT
         COUNT (P.CPROJNUM) ProjectAwarded,
         SUM (MIN (c.calcbtot)) AwardedDollarAmount,
         SUM (COUNT (C.VENDOR)) NumberOfBidders,
         (SUM (COUNT (C.VENDOR)) / (COUNT (P.CPROJNUM))) AverageNumberOfBidder
    FROM BIDDERS C,
         BIDLET B,
         LETPROP L,
         PROPOSAL P
   WHERE     C.LETTING = B.LETTING
         AND P.CONTID = L.LCONTID
         AND C.LETTING = L.LETTING
         AND C.CALL = L.CALL
         AND l.lcontid IN
                (SELECT lcontid
                   FROM letprop c, PROPOSAL d
                  WHERE     datestat IS NOT NULL
                        AND UPPER (letstat) <> 'R'
                        AND UPPER (letstat) <> 'B'
                        AND TRIM (UPPER (TIMELET)) = TRIM ('9:30 A.M.')
                        AND c.LCONTID = d.CONTID)
                        AND (B.DATELET >= TO_DATE ('2011-04-01', 'YYYY-MM-DD')
                        AND B.DATELET <= TO_DATE ('2011-06-30', 'YYYY-MM-DD'))             
GROUP BY l.call

Answer 1

Hi,
If :p_year and :p_quarter are NUMBER variables, containing the year and quarter you want, then you can do something like this:
WITH     got_report_start_date     AS
     SELECT  ADD_MONTHS ( DATE '2000-01-01'
                  , (12 * (:p_year - 2000)) +
                    ( 3 * (:p_quarter - 1))
                  )   AS report_start_date
     FROM    dual
)                                        -- Everything above is NEW
SELECT DISTINCT
         COUNT (P.CPROJNUM) ProjectAwarded,
         SUM (MIN (c.calcbtot)) AwardedDollarAmount,
         SUM (COUNT (C.VENDOR)) NumberOfBidders,
         (SUM (COUNT (C.VENDOR)) / (COUNT (P.CPROJNUM))) AverageNumberOfBidder
    FROM BIDDERS C,
         BIDLET B,
         LETPROP L,
         PROPOSAL P
   ,      got_report_start_date     r                    -- NEW
   WHERE     C.LETTING = B.LETTING
         AND P.CONTID = L.LCONTID
         AND C.LETTING = L.LETTING
         AND C.CALL = L.CALL
         AND l.lcontid IN
                (SELECT lcontid
                   FROM letprop c, PROPOSAL d
                  WHERE     datestat IS NOT NULL
                        AND UPPER (letstat) <> 'R'
                        AND UPPER (letstat)  'B'
                        AND TRIM (UPPER (TIMELET)) = TRIM ('9:30 A.M.')
                        AND c.LCONTID = d.CONTID
         AND B.DATELET >= r.report_start_date               -- CHANGED
         AND B.DATELET <  ADD_MONTHS (r.report_start_date, 3)     -- CHANGEDLook for comments that say NEW or CHANGED; the rest is just what you posted.
Note that you should use < (not <=) when testing the end of the date range, and the date after the < sign is the first date NOT to be included in the results.