How to Determine Values for Missing Months based on Data of Previous Months in T-SQL

Question

I have a set of transactions occurring at specific points in time:

CREATE TABLE Transactions (
    TransactionDate Date NOT NULL,
    TransactionValue Intege         


        

Answer 1

I don't have access to BOL from my phone so this is a rough guide...

First, you need to generate the missing rows for the months you have no data. You can either use a OUTER join to a fixed table or temp table with the timespan you want or from a programmatically created dataset (stored proc or suchlike)

Second, you should look at the new SQL 2008 'analytic' functions, like MAX(value) OVER ( partition clause ) to get the previous value.

(I KNOW Oracle can do this 'cause I needed it to calculate compounded interest calcs between transaction dates - same problem really)

Hope this points you in the right direction...

(Avoid throwing it into a temp table and cursoring over it. Too crude!!!)