Question

I have table effort_sheet as below,

-----------------------------------------------
Pid  WeekendDate  Mon Tue Wed Thr Fri Sat Sun
----------------------------------------------
11   14.10.2012   4    4   5   1   0   0   0
11   07.10.2012   2    2   1   5   3   0   0
12   07.10.2012   2    2   0   0   0   0   0

Here, WeekendDate is date on 'Sun'(last column)

I need to find the date for each Pid when last non-zero value was logged.
So my result should be something like

Pid  LastValueDate
11   11.10.2012
12   02.10.2012

11 -> 11.10.2012 was Thr(value 1)
12 -> 02.10.2012 was Tue(value 2)

As my data is in Excel, an d I am using JDBC-ODBC connection. I would prefer we this could be achieved just with SQL.

My incomplete solution (need to find last_effort_day):

SELECT pid
      ,max(WeekendDate) - (6-last_effort_day) AS end_date
 FROM effort_sheet
GROUP BY pid

Please help.

Answer 1

Try this 
select es.p_id,es.weekenddate-( CASE 
                             WHEN SUN != 0 THEN 0 
                             WHEN SAT != 0 THEN 1 
                             WHEN FRI != 0 THEN 2 
                             WHEN THR != 0 THEN 3 
                             WHEN WED != 0 THEN 4 
                             WHEN TUE != 0 THEN 5 
                             ELSE 6 
                           END )  from(
select p_id,max(weekenddate)dt from effort_sheet group by p_id
  )inner,effort_sheet es
where inner.p_id =es.p_id
AND inner.dt=es.weekenddate;

sqlfiddle link