diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Projection.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Projection.java
index d986a264a..e97202366 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/Projection.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/Projection.java
@@ -1,9 +1,16 @@
+/*
+ * Copyright (c) 2009 Mysema Ltd.
+ * All rights reserved.
+ * 
+ */
 package com.mysema.query.grammar.types;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.ParameterizedType;
+import java.util.HashSet;
+import java.util.Set;
 
 /**
  * Projection provides
@@ -13,6 +20,8 @@ import java.lang.reflect.ParameterizedType;
  */
 public class Projection extends Path.PEntity<Object>{
     
+    private Set<String> fields = new HashSet<String>();
+    
     private String entityName;
     
     private static Method _numberMethod, _comparableMethod;
@@ -37,6 +46,7 @@ public class Projection extends Path.PEntity<Object>{
                 for (Field field : cl.getDeclaredFields()){
                     if (Expr.class.isAssignableFrom(field.getType()) && field.getGenericType() instanceof ParameterizedType){
                         field.setAccessible(true);
+                        fields.add(field.getName());
                         handleField(field);                    
                     }                              
                 }    
@@ -71,4 +81,8 @@ public class Projection extends Path.PEntity<Object>{
         return entityName;
     }
     
+    public void accept(SubQuery<?,?> query){
+        // TODO : validate that the given SubQuery can be projected        
+    }
+    
 }
diff --git a/querydsl-core/src/main/java/com/mysema/query/grammar/types/SubQuery.java b/querydsl-core/src/main/java/com/mysema/query/grammar/types/SubQuery.java
index 2712c6c5d..a924c6b8c 100644
--- a/querydsl-core/src/main/java/com/mysema/query/grammar/types/SubQuery.java
+++ b/querydsl-core/src/main/java/com/mysema/query/grammar/types/SubQuery.java
@@ -38,11 +38,15 @@ public class SubQuery<JM,A> extends Expr<A> implements Query<SubQuery<JM,A>>, Co
     public SubQuery<JM,A> join(EEntity<?> o) {query.join(o); return this;}
     public SubQuery<JM,A> leftJoin(EEntity<?> o) {query.leftJoin(o); return this;}
     public SubQuery<JM,A> orderBy(OrderSpecifier<?>... o) {query.orderBy(o); return this;}
-    public SubQuery<JM,A> select(Expr<?>... o) {query.s(o); return this;}
+    public SubQuery<JM,A> select(Expr<?>... o) {
+        query.s(o); return this;}
     public SubQuery<JM,A> where(EBoolean... o) {query.where(o); return this;}
     public SubQuery<JM,A> with(EBoolean o) {query.with(o); return this;}
     // TODO : add some validation that the given Projection is valid for this subquery
-    public Alias.ASimple<A> as(Projection to) { return new Alias.ASimple<A>(this, to.getName()); }
+    public Alias.ASimple<A> as(Projection to) {
+        to.accept(this);
+        return new Alias.ASimple<A>(this, to.getName()); 
+    }
     public Alias.ASimple<A> as(String to) { return new Alias.ASimple<A>(this, to); }
     
     private static class QueryWithPublicSelect<JM> extends QueryBase<JM,QueryWithPublicSelect<JM>>{