Join and count in SQL Server

Question

I have two tables; let's call them TableA and TableB. Each element of TableB is associated with an element of TableA in a many-to-one relationship. Some elements of TableA may have no corresponding element in TableB.

I need to select every element in TableA, along with a column that will, for each row in the result set, contain the number of elements in TableB that are associated with that row in TableA, and that have a certain property.

Using MS SQL Server 2008 (Needs to also work in SQL Server 2005).

Answer 1

Updated

SELECT A.elementid, A.column1, A.column2, A.column3, 
       COUNT(CASE WHEN B.someColumn > 0 THEN B.elementid ELSE NULL END) Q
FROM TableA A
LEFT JOIN TableB B
ON A.elementid = B.elementid
GROUP BY A.elementid, A.column1, A.column2, A.column3