Calculate running total / running balance

Question

I have a table:

create table Transactions(Tid int,amt int)

With 5 rows:

insert into Transactions values(1, 100)
insert into         


        

Answer 1

If you use version 2012, here is a solution

select *, sum(amt) over (order by Tid) as running_total from Transactions 

For earlier versions

select *,(select sum(amt) from Transactions where Tid<=t.Tid) as running_total from Transactions as t