use lag int the next line after its line have been executed - oracle

Question

This is a very complicated situation for me and I was wondering if someone can help me with it:
Here is my table:
Record_no Type Solde SQLCalculatedPmu DesiredValues
------------------------------------------------------------------------
2570088 Insertion 60 133 133
2636476 Insertion 67 119,104 119,104
2636477 Insertion 68 117,352 117,352
2958292 Insertion 74 107,837 107,837
3148350 Radiation 73 107,837 107,83 <---
3282189 Insertion 80 98,401 98,395
3646066 Insertion 160 49,201 49,198
3783510 Insertion 176 44,728 44,725
3783511 Insertion 177 44,475 44,472
4183663 Insertion 188 41,873 41,87
4183664 Insertion 189 41,651 41,648
4183665 Radiation 188 41,651 41,64 <---
4183666 Insertion 195 40,156 40,145
4183667 Insertion 275 28,474 28,466
4183668 Insertion 291 26,908 26,901
4183669 Insertion 292 26,816 26,809
4183670 Insertion 303 25,842 25,836
4183671 Insertion 304 25,757 25,751
In my table every value in the SQLCalculatedPmu column or desiredValue Column is calculated based on the preceding value.
As you can see, I have calculated the SQLcalculatedPMU column based on the round on 3 decimals. The case is that on each line radiation, the client want to start the next calculation based on 2 decimals instead of 3(represented in the desired values column). Next values will be recalculated. For example line 6 will change as the value in line 5 is now on 2 decimals. I could handle this if there where one single radiation but in my case I have a lot of Radiations and in this case they will change all based on the calculation of the two decimals.
In summary, Here are the steps:
1 - round the value of the preceding row of a raditaiton and put it in the radiation row.
2 - calculate all next insertion rows.
3 - when we reach another radiation we redo steps 1 and 2 and so on
I m using an oracle DB and I m the owner so I can make procedures, insert, update, select.
But I m not familiar with procedures or loops.
For information, this is the formula for SQLCalculatedPmu uses two additional culmns price and number and this is calculated every line cumulativelly for each investor:
(price * number)+(cumulative (price*number) of the preceeding lines)
I tried something like this :
update PMUTemp
set SQLCalculatedPmu =
case when Type = 'Insertion' then
(number*price)+lag(SQLCalculatedPmu ,1) over (partition by investor
order by Record_no)/
(number+lag(solde,1) over (partition by investor order by Record_no))
else
TRUNC(lag(SQLCalculatedPmu,1) over partition by invetor order by Record_no))
end;
but I gave me this error (I think it's because I m looking at the preceiding line that itself is modified during the SQL statement) :
ORA-30486 : window function are allowed only in the SELECT list of a query.
I was wondering if creating a procedure that will be called as many time as the number of radiations would do the job but I m really not good in procedures
Any help
Regards,
just to make my need simpler, all I want is to have the DesiredValues column starting from the SQLCalculatedPmu column. Steps are
1 - on a radiation the value become = trunc(preceding value,2)
2 - calculate all next insertion rows this way : (price * number)+(cumulative (price*number) of the preceeding lines). As the radiation value have changed then I need to recalculate next lines based on it
3 - when we reach another radiation we redo steps 1 and 2 and so on
Kindest regards

Answer 1

You should not need a procedure here -- a SQL update of the Radiation rows in the table would do this quicker and more reliably.
Something like ..
update my_table t1
set (column_1, column_2) =
(select round(column_1,2), round(column_2,2)
from my_table t2
where t2.type = 'Insertion' and
t2.record_no = (select max(t3.record_no)
from my_table t3
where t3.type = 'Insertion' and
t3.record_no < t1.record_no ))
where t1.type = 'Radiation'