Operator functions or?

Question

Hi all,,
In sqldeveloper ,
I have 2 columns named A and B. column 'A' has data 1 for all rows.
column 'B' has data 12 for all rows. ( ref.below example)
my requirement is that, i need to get 'C' column and the first row of 'C' should be the total of A+B i.e, 1+12 which will give the answer 13.
Next row of column 'C' should retrieve the answer as 14. i.e, answer of 1st row of C's data + 2nd row of A's data and so on for all rows. Do i need to use any operator functions or which method can i achieve this?
eg:
A B C
1 12 13
1 12 14
1 12 15
1 12 16
1 12 17
thanks in advance.

Answer 1

What an odd question.
If it is just A+B from the first row and then cumulatively adding A from the subsequent rows then something along the lines of...
SQL> create table tblsum(a number, b number);
Table created.
SQL> insert into tblsum (a, b) values (1,12);
1 row created.
SQL> insert into tblsum (a, b) values (1,12);
1 row created.
SQL> insert into tblsum (a, b) values (1,12);
1 row created.
SQL> insert into tblsum (a, b) values (1,12);
1 row created.
SQL> insert into tblsum (a, b) values (1,12);
1 row created.
SQL> select a, b, sum(a+(case when rownum=1 then b else 0 end)) over (order by rownum) as d from tblsum;
         A          B          D
         1         12         13
         1         12         14
         1         12         15
         1         12         16
         1         12         17
SQL> insert into tblsum (a,b) values (3, 15);
1 row created.
SQL> select a, b, sum(a+(case when rownum=1 then b else 0 end)) over (order by rownum) as d from tblsum;
         A          B          D
         1         12         13
         1         12         14
         1         12         15
         1         12         16
         1         12         17
         3         15         20
6 rows selected.but we really need something to distinguish what order the rows are in... which is difficult when all (or most) of the data is identical.
We could even do something like...
SQL> select a, b, min(b) over ()+count(*) over (order by rownum) from tblsum;
         A          B MIN(B)OVER()+COUNT(*)OVER(ORDERBYROWNUM)
         1         12                                       13
         1         12                                       14
         1         12                                       15
         1         12                                       16
         1         12                                       17But.... why? that's the question.