How to get Historic Data in Oracle

Question

Hi,
THe following query might be useful to generate the consecutive dates from given date to sysdate.
SELECT dt
FROM   ( SELECT to_date('02/19/1981','mm/dd/yyyy')+rownum-1 AS dt
       FROM    user_objects
WHERE  TRUNC(dt)<=TRUNC(SYSDATE);NOw lets consider the basic scott.emp table
The above requirement can be acheived using this query as we may get only 14 records as there are only 14 records in scott.emp table
select ( to_date('02/19/1981','mm/dd/yyyy')+rownum-1) as dt
from scott.emp If we see the scott.emp table there are 2 reocrds with empno 7499,7521 with hiredates 20-feb-81 and 22-feb-81 respectively. on pulling the historic data from19-feb-81 to 04-mar-81 as there are only 14 records in the table we need to get the sum of sal or comm as it is along with those dates in the table.
Assuming there are more than one record for the same date for the dates mentioned above , i have used the following query but could not get the desired output.
Select To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1,
sum(Case When Sal>0 And Trunc(Hiredate)= (To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1)
Then (Sal)
Else 0 End ) As Hist_Sal,
sum(Case When Nvl(Comm,0)>= 0 And Trunc(Hiredate)= (To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1)
Then (Nvl(Comm,0))
Else 0 End) As hist_comm
From Scott.Emp
Group By To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1
order by 1; I have tried the other option also and I could get the desired output.THe query goes like this:
--Success Statement
Select To_Char(Rt.Business_Date , 'Day,Mon DD,yyyy') As Business_Date ,To_Date(Rt.Business_Date) As Hist_date,
( Select sum(sal)
From Scott.Emp  Slm
Where Trunc (Hiredate) = Trunc(Rt.Business_Date)
) as hist_sal
FROM
(select ((TO_DATE('02/19/1981','mm/dd/yyyy')-1)+rnm) as business_date from (select rownum rnm from user_objects)) rt
Where
Trunc(Rt.Business_Date) Between To_Date('02/19/1981','mm/dd/yyyy') And To_Date('10/31/2012','mm/dd/yyyy')
order by Hist_date;But i want to get the historic dates/data to be genearted from scott.emp table insetead of using this logic *(select ((TO_DATE('02/19/1981','mm/dd/yyyy')-1)+rnm) as business_date from (select rownum rnm from user_objects)) rt* as written in Success Statement
As it would be helpful for my requirement ,else I need to write subqueries for all the cols i need as i have written in the above success statement.
please advise.
Regards,

Answer 1

sri wrote:
Hi,
THe following query might be useful to generate the consecutive dates from given date to sysdate.
SELECT dt
FROM   ( SELECT to_date('02/19/1981','mm/dd/yyyy')+rownum-1 AS dt
FROM    user_objects
WHERE  TRUNC(dt)<=TRUNC(SYSDATE);
Unless you're using Oracle 8 (or older) then it's more efficient to say:
SELECT     start_dt + LEVEL - 1     AS dt
FROM     (
          SELECT     TO_DATE ('02/19/1981', 'MM/DD/YYYY')     AS start_dt
          ,     TRUNC (SYSDATE)                           AS end_dt
          FROM     dual
CONNECT BY  LEVEL     <= 1 + (end_dt - start_dt)
;and it doesn't depend on how many rows happen to be in user_objects.
NOw lets consider the basic scott.emp table
The above requirement can be acheived using this query as we may get only 14 records as there are only 14 records in scott.emp table
select ( to_date('02/19/1981','mm/dd/yyyy')+rownum-1) as dt
from scott.emp If we see the scott.emp table there are 2 reocrds with empno 7499,7521 with hiredates 20-feb-81 and 22-feb-81 respectively. on pulling the historic data from19-feb-81 to 04-mar-81 as there are only 14 records in the table we need to get the sum of sal or comm as it is along with those dates in the table.
Assuming there are more than one record for the same date for the dates mentioned above , i have used the following query but could not get the desired output.
Select To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1,
sum(Case When Sal>0 And Trunc(Hiredate)= (To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1)
Then (Sal)
Else 0 End ) As Hist_Sal,
sum(Case When Nvl(Comm,0)>= 0 And Trunc(Hiredate)= (To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1)
Then (Nvl(Comm,0))
Else 0 End) As hist_comm
From Scott.Emp
Group By To_Date('02/19/1981','mm/dd/yyyy')+Rownum-1
order by 1; I have tried the other option also and I could get the desired output.THe query goes like this:
--Success Statement
Select To_Char(Rt.Business_Date , 'Day,Mon DD,yyyy') As Business_Date ,To_Date(Rt.Business_Date) As Hist_date,
( Select sum(sal)
From Scott.Emp  Slm
Where Trunc (Hiredate) = Trunc(Rt.Business_Date)
) as hist_sal
FROM
(select ((TO_DATE('02/19/1981','mm/dd/yyyy')-1)+rnm) as business_date from (select rownum rnm from user_objects)) rt
Where
Trunc(Rt.Business_Date) Between To_Date('02/19/1981','mm/dd/yyyy') And To_Date('10/31/2012','mm/dd/yyyy')
order by Hist_date;But i want to get the historic dates/data to be genearted from scott.emp table insetead of using this logic *(select ((TO_DATE('02/19/1981','mm/dd/yyyy')-1)+rnm) as business_date from (select rownum rnm from user_objects)) rt* as written in Success Statement
As it would be helpful for my requirement ,else I need to write subqueries for all the cols i need as i have written in the above success statement.Sorry, I'm not sure what you're asking.
Do you want to know if there's a simpler and/or more efficient way to get the same results as the 2nd query you posted above?
Here's one way:
WITH      all_dates   AS
     SELECT     start_dt + LEVEL - 1     AS dt
     FROM     (
              SELECT     TO_DATE ('02/19/1981', 'MM/DD/YYYY')     AS start_dt
              ,             TO_DATE ('10/31/2012', 'MM/DD/YYYY')     AS end_dt
              FROM    dual
     CONNECT BY  LEVEL     <= 1 + (end_dt - start_dt)
SELECT       TO_CHAR (a.dt, 'Day, Mon DD, YYYY')     AS business_date
,       SUM (e.sal)                                AS hist_sal
FROM              all_dates  a
LEFT OUTER JOIN      scott.emp  e  ON  e.hiredate = a.dt
GROUP BY  a.dt
ORDER BY  a.dt
;For testing purposes, it would be a lot clearer if you made the end_dt something like April 5, 1981 rather than October 31, 2012.
I hope this answers your question.
If not, post the results you want from the data in scott.emp, given some reasonable date range. (I suggest Nov. 16, 1981 through Jan. 24, 1982; that includes December 3, 1981 which has 2 rows with the same hiredate.)
Explain, using specific examples, how you get those results from that data.
Always say which version of Oracle you're using (e.g., 11.2.0.2.0).
See the forum FAQ {message:id=9360002}