Total Oracle sum

// Add the values of a column in the current row to the values of the column in the previous row, that is, the sum of the total values:
With t (
Select 1 val from dual union all
Select 3 from dual union all
Select 5 from dual union all
Select 7 from dual union all
Select 9 from dual)
Select val,
Sum (val)
Over (order by rownum rows between unbounded preceding and current row)
Sum_val
From t
Group by rownum, val
Order by rownum;
VAL SUM_VAL
--------------------
1 1
3 4
5 9
7 16
9 25
// Resolution:
// Sum (val) calculates the sum;
// Order by rownum sorts query records by pseudo-column rownum;
// Between unbounded preceding and current row: defines the start and end points of the window;
// Unbounded preceding: the start point of the window includes all rows read;
// Current row: The end of the window is the current row. The default value can be omitted;