Calculate previous SUM value

I have 2 SQL Server 2005 tables: Names and Scores

Names table:

  NameID, Name,   Age
  1,      'John', 23
  2,      'Ryan', 20

Scores table:

  ScoreID, NameID, ScoreDate,  ScoreValue
  1,       1,      01/01/2011, 250
  2,       1,      02/01/2011, 300
  3,       1,      03/01/2011, 100
  4,       2,      01/01/2011, 150
  5,       2,      02/01/2011, 350
  6,       2,      03/01/2011, 200

I want to get开发者_如何学JAVA for a given month:

Name, Age, current ScoreValue, sum(ScoreValue) for previous months

Something like this form the month of february:

John, 23, 300, 550
Ryan, 20, 350, 500

---

Think this is what you want:

select n.Name,
       s1.ScoreId, 
       s1.nameId, 
       s1.ScoreValue,
       sum(s2.ScoreValue) Prevmonths
from   names n
       inner join scores s1 on n.NameId = s1.NameId
       left  join scores s2 -- make left join in case no previous month
         on  s1.NameId = s2.NameId 
         and s1.ScoreDate >= s2.ScoreDate -- >= means include current onth
group by n.Name,
       s1.ScoreId, 
       s1.nameId, 
       s1.ScoreValue

GJ