Running total refers to the sum of values in all cells of a column that precedes the next cell in that particular column.
Using Window Function
Assuming, the table has 2 columns, col1 is primary key with data type integer and col2 is integer data type values. To calculate running total on col2 write a query as
select col1, col2,sum(col2) over(order by col1) as runnintotal from tablename
using window function is more performance efficient.