public static HashSet <ColumnExpression> Gather(Expression expression)
{
var visitor = new ReferencedColumnGatherer();
visitor.Visit(expression);
return(visitor.columns);
}
protected override Expression VisitSelect(SelectExpression select)
{
ILookup <TableAlias, ColumnExpression> saveColumns = columns;
columns = ReferencedColumnGatherer.Gather(select).ToLookup(c => c.Alias);
JoinType?saveLastJoin = lastJoin;
lastJoin = null;
Expression result = base.VisitSelect(select);
columns = saveColumns;
lastJoin = saveLastJoin;
return(result);
}
