Sql query ..need idea to write complex query

Question

Hi there,
I have assigned the task to write a sql query to get the output as the below stored proc does.
In the proc conditions are given with IF statements. I really dont know how to give all the conditions for the period in a single sql query as I'm not much used to sql quries.
Is anyone could help me?
Any suggestions pls . writing complicated query is nightmare. no idea . if possible help me...
create or replace PROCEDURE vpp_station_summary_report (
in_user_id                     IN  VARCHAR2,
in_report_id      IN  NUMBER,
in_time_from                IN      vppstation.avi_status_history.status_eff_date%TYPE,
in_time_to                  IN  vppstation.avi_status_history.status_eff_date%TYPE,
result                               OUT SYS_REFCURSOR)
AS
CURSOR station_loop IS
   SELECT ash.station_id,
          ash.avi_id,
          ash.state_id,
          ash.state_eff_date
   FROM   vppstation.avi_state_history ash
   JOIN   vpproadside.vpp_report_stations
     ON   vpp_report_stations.station_id             = ash.station_id
    AND   vpp_report_stations.vpp_report_seq_number  = in_report_id
   WHERE  ash.state_eff_date BETWEEN in_time_from AND in_time_to
   ORDER BY ash.station_id,
            ash.avi_id,
            ash.state_eff_date,
            ash.ash_id;
-- cursor to find the 'entry state' i.e. the state the AVI was in AT the time of
-- in_time_from
CURSOR entry_state (
          state_station_id vppstation.avi_state_history.station_id%TYPE,
          state_avi_id     vppstation.avi_state_history.avi_id%TYPE,
          state_state_date vppstation.avi_state_history.state_eff_date%TYPE
IS
   SELECT ash.state_id
   FROM   vppstation.avi_state_history ash
   WHERE  ash.station_id = state_station_id
     AND  ash.avi_id = state_avi_id
     AND  ash.state_eff_date < state_state_date
   ORDER BY ash.state_eff_date DESC,
            ash.ash_id DESC;
current_station_id         vppstation.avi_state_history.station_id%TYPE;
current_avi_id             vppstation.avi_state_history.avi_id%TYPE;
current_state_id           vppstation.avi_state_history.state_id%TYPE;
current_state_eff_date     vppstation.avi_state_history.state_eff_date%TYPE;
period_length NUMBER;
next_station_id     vppstation.avi_state_history.station_id%TYPE;
next_avi_id         vppstation.avi_state_history.avi_id%TYPE;
next_state_id       vppstation.avi_state_history.state_id%TYPE;
next_state_eff_date vppstation.avi_state_history.state_eff_date%TYPE;
station_open_total       NUMBER;
station_closed_total     NUMBER;
station_all_report_total NUMBER;
current_station_name vpproadside.vpp_station_summary.station_name%TYPE;
state_open       vppstation.avi_control_state_code.state_id%TYPE;
state_closed     vppstation.avi_control_state_code.state_id%TYPE;
state_all_report vppstation.avi_control_state_code.state_id%TYPE;
BEGIN
SELECT state_id
INTO   state_open
FROM   vppstation.avi_control_state_code
WHERE  state_type = 'E'
AND    state_active_ind = 'A';
SELECT state_id
INTO   state_closed
FROM   vppstation.avi_control_state_code
WHERE  state_type = 'D'
AND    state_active_ind = 'A';
SELECT state_id
INTO   state_all_report
FROM   vppstation.avi_control_state_code
WHERE  state_type = 'S'
AND    state_active_ind = 'A';
current_station_id := -1;
current_avi_id     := -1;
current_state_id   := state_closed;
current_state_eff_date := in_time_from;
station_open_total       := 0.0;
station_closed_total     := 0.0;
station_all_report_total := 0.0;
-- for starters - ensure that there is report data for all requested stations...
INSERT INTO vpproadside.vpp_station_summary
      vpp_report_seq_number,
      station_id,
      station_name,
      ln_number,
      lane_name,
      station_open,
      station_close,
      station_all_report,
      station_total
  SELECT in_report_id,
         vrs.station_id,
         si.station_name,
         l.ln_number,
         l.lane_name,
         0.0,
         0.0,
         0.0,
         0.0
  FROM vpproadside.vpp_report_stations vrs
  LEFT OUTER JOIN  vpproadside.stations_installed si
    ON  si.station_id = vrs.station_id
  LEFT OUTER JOIN vppstation.lane_name l
    ON l.station_id = vrs.station_id
  WHERE vrs.vpp_report_seq_number  = in_report_id;
-- loop over state history and update information for all stations found
OPEN station_loop;
LOOP
  FETCH station_loop
  INTO
        next_station_id,
        next_avi_id,
        next_state_id,
        next_state_eff_date;
  IF station_loop%NOTFOUND THEN
    next_station_id := -1;
    next_avi_id     := -1;
  END IF;
  -- if station/avi has changed take the end of the report period
  IF    (next_station_id <> current_station_id)
     OR (next_avi_id     <> current_avi_id)
  THEN
    period_length := in_time_to - current_state_eff_date;
  ELSE
    -- otherwise the start of the next period marks the end of the current period
    period_length := next_state_eff_date - current_state_eff_date;
  END IF;
  -- if we have a real station id then do some work...
  IF (current_station_id <> -1) THEN
    -- determine which category the period fits to and apply calculation
    IF current_state_id = state_open THEN
      station_open_total := station_open_total + period_length - 1;
    ELSIF current_state_id = state_closed THEN
      station_closed_total := station_closed_total + period_length - 1;
    ELSIF current_state_id = state_all_report THEN
      station_all_report_total := station_all_report_total + period_length - 1;
    ELSE
      RAISE_APPLICATION_ERROR(-20111, 'Error: found unknown state code on avi_state_history - ' || current_state_id );
    END IF;
    -- if the station/avi has changed then commit changes to db
    IF    (next_station_id <> current_station_id)
       OR (next_avi_id     <> current_avi_id)
    THEN
      UPDATE vpproadside.vpp_station_summary
      SET
          station_open       = station_open_total,
          station_close      = station_closed_total,
          station_all_report = station_all_report_total
      WHERE vpp_report_seq_number = in_report_id
      AND   station_id = current_station_id
      AND   ln_number  = current_avi_id;
      -- reset counts
      station_open_total       := 0.0;
      station_closed_total     := 0.0;
      station_all_report_total := 0.0;
    END IF;
  END IF;
  -- if we got past the last record then stop processing
  EXIT WHEN station_loop%NOTFOUND;
  -- if the station/avi is changing, get the state that was 'current' at in_time_from
  IF    (next_station_id <> current_station_id)
     OR (next_avi_id     <> current_avi_id)
  THEN
    current_state_eff_date := in_time_from;
    OPEN entry_state (
           next_station_id,
           next_avi_id,
           in_time_from
    FETCH entry_state
    INTO  current_state_id;
    IF entry_state%NOTFOUND THEN
      current_state_id := state_closed;
    END IF;
    CLOSE entry_state;
    period_length := next_state_eff_date - current_state_eff_date;
    IF current_state_id = state_open THEN
      station_open_total := station_open_total + period_length;
    ELSIF current_state_id = state_closed THEN
      station_closed_total := station_closed_total + period_length;
    ELSIF current_state_id = state_all_report THEN
      station_all_report_total := station_all_report_total + period_length;
    ELSE
        RAISE_APPLICATION_ERROR(-20111, 'Error: found unknown state code on avi_state_history - ' || current_state_id );
    END IF;
  END IF;
  current_state_id       := next_state_id;
  current_state_eff_date := next_state_eff_date;
  current_station_id     := next_station_id;
  current_avi_id         := next_avi_id;
END LOOP;
CLOSE station_loop;
-- update the totals for the percentage calculation
UPDATE vpproadside.vpp_station_summary
SET
       station_total = station_open + station_close+ station_all_report
WHERE   vpp_report_seq_number = in_report_id;
-- 'fix' the totals that are still zero to avoid divide by zero errors...
--       note: all the percentages will still come out as zero since the total
--             was zero
UPDATE vpproadside.vpp_station_summary
SET
       station_total = 1.0
WHERE  vpp_report_seq_number = in_report_id
AND    station_total = 0.0;
OPEN result FOR
SELECT station_name "Site Name",
       lane_name    "Lane Name",
       TO_CHAR((station_open       / station_total) * 100.0, 'FM990.0999') || '%' "Open %",
       TO_CHAR((station_close      / station_total) * 100.0, 'FM990.0999') || '%' "Closed %",
       TO_CHAR((station_all_report / station_total) * 100.0, 'FM990.0999') || '%' "All Report %"
FROM vpproadside.vpp_station_summary
WHERE vpp_report_seq_number = in_report_id
ORDER BY UPPER(station_name),
         UPPER(lane_name);
DELETE FROM vpproadside.vpp_station_summary
WHERE vpp_report_seq_number = in_report_id;
END;Edited by: Indhu Ram on Mar 10, 2010 9:51 AM
Edited by: Indhu Ram on Mar 10, 2010 9:56 AM
Edited by: Indhu Ram on Mar 10, 2010 10:58 AM
Edited by: Indhu Ram on Mar 10, 2010 11:12 AM

Answer 1

Exactly dont know what you are asking for but I can suggest you some tips here
- If you want to check the condition in SQL query then you can use CASE statement into select clause i.e.
SELECT CASE when table1.a=table2.b then table1.c else table2.c END, ... more case..., table columns...
FROM table1, table2
WHERE
<some conditions>
- If you want to achive same functionality (SELECT only, not UPDATE/INSERT/DELETE) then you can convert the part of same procedure into function and can use the same function into your query by passing the parameters.
something like this
SELECT function_name(parameter1, parameter2....) from dual
Hope this will help