public void MaterializeSubQueries(Session session)
{
HashSet <SubQuery> set = new HashSet <SubQuery>();
for (int i = 0; i < this.Subqueries.Length; i++)
{
SubQuery item = this.Subqueries[i];
if (set.Add(item) && !item.IsCorrelated())
{
item.Materialise(session);
}
}
}