diff --git a/caravel/migrations/versions/6113409d871f_.py b/caravel/migrations/versions/6113409d871f_.py
index dfe4ddab4815..71ca91cf80d1 100644
--- a/caravel/migrations/versions/6113409d871f_.py
+++ b/caravel/migrations/versions/6113409d871f_.py
@@ -10,9 +10,6 @@
 revision = '6113409d871f'
 down_revision = ('c3a8f8611885', 'b4a0abe21630')
 
-from alembic import op
-import sqlalchemy as sa
-
 
 def upgrade():
     pass
diff --git a/caravel/migrations/versions/b4a0abe21630_post_aggs.py b/caravel/migrations/versions/b4a0abe21630_post_aggs.py
index b913323b2ac9..fd8d48ff3921 100644
--- a/caravel/migrations/versions/b4a0abe21630_post_aggs.py
+++ b/caravel/migrations/versions/b4a0abe21630_post_aggs.py
@@ -12,7 +12,6 @@
 
 from alembic import op
 import sqlalchemy as sa
-from sqlalchemy.dialects import mysql
 
 
 def upgrade():
diff --git a/caravel/models.py b/caravel/models.py
index f35c340e62f8..c3a7d73352b2 100644
--- a/caravel/models.py
+++ b/caravel/models.py
@@ -535,6 +535,11 @@ def metrics_combo(self):
                 for m in self.metrics],
             key=lambda x: x[1])
 
+    @property
+    # TODO: Sqlable shouldn't have this for post aggregators are only for Druid
+    def post_aggregators_combo(self):
+        return []
+
     @property
     def sql_url(self):
         return self.database.sql_url + "?table_name=" + str(self.table_name)
@@ -1387,6 +1392,7 @@ class DruidPostAggregator(Model):
     json = Column(Text)
     description = Column(Text)
 
+
 class FavStar(Model):
     __tablename__ = 'favstar'