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

In SQL Server 2008+

SELECT  T1.* ,
        T2.RunningSum
FROM    dbo.Transactions As T1
        CROSS APPLY ( SELECT    SUM(amt) AS RunningSum
                      FROM      dbo.Transactions AS CAT1
                      WHERE     ( CAT1.TId <= T1.TId )
                    ) AS T2

In SQL server 2012+

SELECT  * ,
        SUM(T1.amt) OVER ( ORDER BY T1.TId 
                        ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW ) AS RunningTotal
FROM    dbo.Transactions AS t1