diff --git a/__init__.py b/__init__.py
index 78f9b5e..be1d1ca 100644
--- a/__init__.py
+++ b/__init__.py
@@ -66,6 +66,22 @@ class Operator(QMixin):
     __nonzero__ = __bool__
 
 
+class F(object):
+
+    def __init__(self, value):
+        self.value = value
+
+    def __repr__(self,):
+        return "%s" % self.value
+
+    __str__ = __repr__
+
+    def __bool__(self):
+        return bool(self.value)
+
+    __nonzero__ = __bool__
+
+
 class Q(QMixin):
     lookup_types = [
         'iexact', 'contains', 'icontains',
@@ -101,6 +117,9 @@ class Q(QMixin):
         if isinstance(value, datetime.date):
             return "'%s'" % value.strftime("%Y-%m-%d")
 
+        if isinstance(value, F):
+            return value
+
         return "'%s'" % value
 
     def _process(self, compose_column, value):
@@ -152,9 +171,10 @@ class Q(QMixin):
 
 class SQLQuery(object):
 
-    def __init__(self, table=None):
+    def __init__(self, table=None, sql_mode="MYSQL"):
         if table:
             self._table = table
+        self.sql_mode = sql_mode
         self._values = []
         self._order_by = []
         self._group_by = []
@@ -218,7 +238,6 @@ class SQLCompiler(object):
         select = self._extra.get("select", None)
         if select:
             return ", " + select
-        return ""
 
     def get_table(self,):
         return self._table
@@ -228,8 +247,6 @@ class SQLCompiler(object):
         if filters:
             return "WHERE " + str(filters)
 
-        return ""
-
     def get_order_by(self,):
         conds = []
         for cond in self._order_by:
@@ -237,29 +254,26 @@ class SQLCompiler(object):
             column = cond
             try:
                 if cond[0] == "-":
-                    order = "desc"
+                    order = " DESC"
                     column = cond[1:]
             except:
                 pass
 
-            conds.append("{0} {1}".format(column, order))
+            conds.append("{0}{1}".format(column, order))
 
         if conds:
             return "ORDER BY " + ", ".join(conds)
-        return ""
 
     def get_group_by(self,):
         if self._group_by:
             return "GROUP BY " + ", ".join(self._group_by)
-        return ""
 
     def get_joins(self,):
         if self._joins:
             return "  ".join(self._joins)
-        return ""
 
     def get_limits(self,):
-        if self._limits:
+        if self._limits and self.sql_mode != "SQL_SERVER":
             offset = self._limits.start
             limit = self._limits.stop
             if offset:
@@ -268,28 +282,18 @@ class SQLCompiler(object):
             if offset:
                 str += " OFFSET {0}".format(offset)
             return str
-        return ""
+
+    def get_top(self,):
+        if self._limits and self.sql_mode == "SQL_SERVER":
+            return "TOP {0}".format(self._limits.stop)
 
     def _compile(self):
-        sql = """
-        SELECT {columns}{extra_columns}
-        FROM {table}
-        {joins}
-        {where}
-        {group_by}
-        {order_by}
-        {limits}
-        """.format(
-            columns=self.get_columns(),
-            extra_columns=self.get_extra_columns(),
-            table=self.get_table(),
-            joins=self.get_joins(),
-            where=self.get_where(),
-            group_by=self.get_group_by(),
-            order_by=self.get_order_by(),
-            limits=self.get_limits()
-        )
-        return sql
+        sql_all = [
+            "SELECT", self.get_top(), self.get_columns(), self.get_extra_columns(),
+            "FROM", self.get_table(), self.get_joins(), self.get_where(),
+            self.get_group_by(), self.get_order_by(), self.get_limits()]
+
+        return " ".join([item for item in sql_all if item])
 
     def __repr__(self):
         return self._compile()
@@ -305,4 +309,4 @@ class SQLModel(object):
 
     @classproperty
     def objects(cls):
-        return Queryset(cls.table)
+        return Queryset(cls.table, getattr(cls, 'sql_mode', None))
diff --git a/tests.py b/tests.py
index d0870e7..a5ebd91 100644
--- a/tests.py
+++ b/tests.py
@@ -1,6 +1,6 @@
 import unittest
 import datetime
-from . import Q
+from . import Q, Queryset, F
 
 
 class TestSqlBuilder(unittest.TestCase):
@@ -22,6 +22,27 @@ class TestSqlBuilder(unittest.TestCase):
         self.assertEqual(str(Q(fecha__year__lte=2012)), "(DATEPART('year', fecha)<=2012)")
         self.assertEqual(str(Q(fecha__year=2012)), "(DATEPART('year', fecha)=2012)")
 
+    def test_limits(self):
+        self.assertEqual(Queryset("table")[:10].get_limits(), "LIMIT 10")
+        self.assertEqual(Queryset("table")[1:10].get_limits(), "LIMIT 9 OFFSET 1")
+
+    def test_compound(self):
+        qs = Queryset("users", "SQL_SERVER")\
+            .filter(nombre="jose")\
+            .order_by( "nombre", "-fecha")\
+            .filter(fecha__lte=F("now()"))[:10]
+
+        self.assertEqual(
+            str(qs), "SELECT TOP 10 * FROM users WHERE ((nombre='jose') AND (fecha<=now())) ORDER BY nombre, fecha DESC")
+
+        qs = Queryset("users")\
+            .filter(nombre="jose")\
+            .order_by( "nombre", "-fecha")\
+            .filter(fecha__lte=F("now()"))[:10]
+
+        self.assertEqual(
+            str(qs), "SELECT * FROM users WHERE ((nombre='jose') AND (fecha<=now())) ORDER BY nombre, fecha DESC LIMIT 10")
+
 
 if __name__ == '__main__':
     unittest.main()