diff --git a/siuba/sql/verbs.py b/siuba/sql/verbs.py
index 6b4731ca..8caeeec1 100644
--- a/siuba/sql/verbs.py
+++ b/siuba/sql/verbs.py
@@ -94,11 +94,14 @@ def exit(self, node):
             name = self._get_unique_name('win', self.window_cte.columns)
             label = col_expr.label(name)
 
-            # optionally put into CTE, and return its resulting column
-            self.window_cte.append_column(label)
-            win_col = self.window_cte.c.values()[-1]
-
+            # put into CTE, and return its resulting column, so that subsequent
+            # operations will refer to the window column on window_cte. Note that
+            # the operations will use the actual column, so may need to use the
+            # ClauseAdaptor to make it a reference to the label
+            self.window_cte = self.window_cte.column(label)
+            win_col = lift_inner_cols(self.window_cte).values()[-1]
             self.windows.append(win_col)
+
             return win_col
                 
         return col_expr
@@ -120,7 +123,7 @@ def _get_unique_name(prefix, columns):
 def track_call_windows(call, columns, group_by, order_by, window_cte = None):
     listener = WindowReplacer(columns, group_by, order_by, window_cte)
     col = listener.enter(call)
-    return col, listener.windows
+    return col, listener.windows, listener.window_cte
 
 
 def lift_inner_cols(tbl):
@@ -474,7 +477,8 @@ def _filter(__data, *args):
             new_call = __data.shape_call(arg, verb_name = "Filter", arg_name = ii)
             #var_cols = new_call.op_vars(attr_calls = False)
 
-            col_expr, win_cols = __data.track_call_windows(
+            # note that a new win_sel is returned, w/ window columns appended
+            col_expr, win_cols, win_sel = __data.track_call_windows(
                     new_call,
                     sel.columns,
                     window_cte = win_sel
@@ -490,16 +494,20 @@ def _filter(__data, *args):
 
     # first cte, windows ----
     if len(windows):
+        
+        for col in windows:
+            win_sel = win_sel.column(col)
         win_alias = win_sel.alias()
 
+
         # because track_call_windows in the loop above used select.append_column
         # multiple times, sqlalchemy doesn't know our window columns are the ones
         # in the final mutated for of win_sel
-        col_key_map = {col.key: col for col in win_alias.columns.values()}
-        equivalents = {col: [col_key_map[col.key]] for col in windows}
+        #col_key_map = {col.key: col for col in win_alias.columns.values()}
+        #equivalents = {col: [col_key_map[col.key]] for col in windows}
 
         # move non-window functions to refer to win_sel clause (not the innermost) ---
-        bool_clause = sql.util.ClauseAdapter(win_alias, equivalents = equivalents) \
+        bool_clause = sql.util.ClauseAdapter(win_alias) \
                 .traverse(bool_clause)
 
         orig_cols = [win_alias.columns[k] for k in sel.columns.keys()]
@@ -554,7 +562,7 @@ def _mutate_select(sel, colname, func, labs, __data):
         sel = cte.select()
 
     # evaluate call expr on columns, making sure to use group vars
-    new_col, windows = __data.track_call_windows(func, columns)
+    new_col, windows, _ = __data.track_call_windows(func, columns)
 
     # replacing an existing column, so strip it from select statement
     if replace_col:
@@ -749,13 +757,13 @@ def _group_by(__data, *args, add = False, **kwargs):
     else:
         data = __data
 
-    cols = data.last_op.columns
-
     # put kwarg grouping vars last, so similar order to function call
     groups =  tuple(simple_varname(arg) for arg in args) + tuple(kwargs)
     if None in groups:
         raise NotImplementedError("Complex expressions not supported in sql group_by")
 
+    # ensure group_by variables are in the select columns
+    cols = data.last_op.alias().columns
     unmatched = set(groups) - set(cols.keys())
     if unmatched:
         raise KeyError("group_by specifies columns missing from table: %s" %unmatched)
@@ -939,8 +947,11 @@ def _anti_join(left, right = None, on = None, *args, sql_on = None):
 
     # create inner join ----
     #not_exists = ~sql.exists([1], from_obj = right_sel).where(bool_clause)
-    not_exists = ~_sql_select([1]).select_from(right_sel).where(bool_clause).exists()
-    sel = left_sel.select().where(not_exists)
+    exists_clause = _sql_select([sql.literal(1)]) \
+            .select_from(right_sel) \
+            .where(bool_clause)
+
+    sel = left_sel.select().where(~sql.exists(exists_clause))
     
     return left.append_op(sel, order_by = tuple())