Query Conversion

Question

Hi, I am new in oracle. I have one BI query as follows:
case
when TimestampDiff(SQL_TSI_DAY, Dim_W_SRVREQ_D.OPEN_DT, ifnull(Dim_W_SRVREQ_D.CLOSE_DT , TIMESTAMP '2009-06-08 00:00:00.000')) <= 5 then 'A: <= 5'
when TimestampDiff(SQL_TSI_DAY, Dim_W_SRVREQ_D.OPEN_DT, ifnull(Dim_W_SRVREQ_D.CLOSE_DT , TIMESTAMP '2009-06-08 00:00:00.000')) <= 10 then 'B: 6 - 10' else 'G: 61+' end.
Now i wanna in oracle. So searched internet and got the query as follows:
case
when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 5 then 'A: <= 5'
when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 10 then 'B: 6 - 10'
else 'G: 61+' end.
This query is correct. Can you explain the above query, if it is correct. Otherwise please give a solution.
Thanks for advance.

Answer 1

In oracle,
select a.days as Days_Category,count(a.ID) as No_of_SRs,a.severity
from
(select a.SEV_CD as severity, (case when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) is null then 'A: >= 5'
when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 5 then 'A: <= 5'
when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 10 then 'B: 6 - 10'
when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 15 then 'C: 11 - 15'
     when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 30 then 'D: 16 - 30'
     when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 45 then 'E: 31 - 45'
when trunc((((86400*(a.OPEN_DT-NVL(a.CLOSE_DT,current_date)))/60)/60)/24) <= 60 then 'F: 46 - 60'
else 'G: 61+' end) as days,b.SR_WID as id from W_SRVREQ_D a,W_SRVREQ_F b where a.ROW_WID = b.SR_WID) a group by a.days order by 1
In which, following columns are date datatype.
CLOSE_DT, OPEN_DT