diff --git a/superset/connectors/sqla/models.py b/superset/connectors/sqla/models.py
index 147c667df0..0d06bfbde0 100644
--- a/superset/connectors/sqla/models.py
+++ b/superset/connectors/sqla/models.py
@@ -285,10 +285,12 @@ class SqlaTable(Model, BaseDatasource):
         """
         cols = {col.column_name: col for col in self.columns}
         target_col = cols[column_name]
+        tp = self.get_template_processor()
+        db_engine_spec = self.database.db_engine_spec
 
         qry = (
             select([target_col.sqla_col])
-            .select_from(self.get_from_clause())
+            .select_from(self.get_from_clause(tp, db_engine_spec))
             .distinct(column_name)
         )
         if limit:
@@ -322,7 +324,6 @@ class SqlaTable(Model, BaseDatasource):
         )
         logging.info(sql)
         sql = sqlparse.format(sql, reindent=True)
-        sql = self.database.db_engine_spec.sql_preprocessor(sql)
         return sql
 
     def get_sqla_table(self):
@@ -331,12 +332,14 @@ class SqlaTable(Model, BaseDatasource):
             tbl.schema = self.schema
         return tbl
 
-    def get_from_clause(self, template_processor=None):
+    def get_from_clause(self, template_processor=None, db_engine_spec=None):
         # Supporting arbitrary SQL statements in place of tables
         if self.sql:
             from_sql = self.sql
             if template_processor:
                 from_sql = template_processor.process_template(from_sql)
+            if db_engine_spec:
+                from_sql = db_engine_spec.escape_sql(from_sql)
             return TextAsFrom(sa.text(from_sql), []).alias('expr_qry')
         return self.get_sqla_table()
 
@@ -367,13 +370,14 @@ class SqlaTable(Model, BaseDatasource):
             'form_data': form_data,
         }
         template_processor = self.get_template_processor(**template_kwargs)
+        db_engine_spec = self.database.db_engine_spec
 
         # For backward compatibility
         if granularity not in self.dttm_cols:
             granularity = self.main_dttm_col
 
         # Database spec supports join-free timeslot grouping
-        time_groupby_inline = self.database.db_engine_spec.time_groupby_inline
+        time_groupby_inline = db_engine_spec.time_groupby_inline
 
         cols = {col.column_name: col for col in self.columns}
         metrics_dict = {m.metric_name: m for m in self.metrics}
@@ -428,7 +432,7 @@ class SqlaTable(Model, BaseDatasource):
                 groupby_exprs += [timestamp]
 
             # Use main dttm column to support index with secondary dttm columns
-            if self.database.db_engine_spec.time_secondary_columns and \
+            if db_engine_spec.time_secondary_columns and \
                     self.main_dttm_col in self.dttm_cols and \
                     self.main_dttm_col != dttm_col.column_name:
                 time_filters.append(cols[self.main_dttm_col].
@@ -438,7 +442,7 @@ class SqlaTable(Model, BaseDatasource):
         select_exprs += metrics_exprs
         qry = sa.select(select_exprs)
 
-        tbl = self.get_from_clause(template_processor)
+        tbl = self.get_from_clause(template_processor, db_engine_spec)
 
         if not columns:
             qry = qry.group_by(*groupby_exprs)
diff --git a/superset/db_engine_specs.py b/superset/db_engine_specs.py
index b460226c1a..d08f2a8feb 100644
--- a/superset/db_engine_specs.py
+++ b/superset/db_engine_specs.py
@@ -73,6 +73,11 @@ class BaseEngineSpec(object):
         """Returns engine-specific table metadata"""
         return {}
 
+    @classmethod
+    def escape_sql(cls, sql):
+        """Escapes the raw SQL"""
+        return sql
+
     @classmethod
     def convert_dttm(cls, target_type, dttm):
         return "'{}'".format(dttm.strftime('%Y-%m-%d %H:%M:%S'))
@@ -139,14 +144,6 @@ class BaseEngineSpec(object):
         """
         return uri
 
-    @classmethod
-    def sql_preprocessor(cls, sql):
-        """If the SQL needs to be altered prior to running it
-
-        For example Presto needs to double `%` characters
-        """
-        return sql
-
     @classmethod
     def patch(cls):
         pass
@@ -399,6 +396,10 @@ class PrestoEngineSpec(BaseEngineSpec):
             uri.database = database
         return uri
 
+    @classmethod
+    def escape_sql(cls, sql):
+        return re.sub(r'%%|%', "%%", sql)
+
     @classmethod
     def convert_dttm(cls, target_type, dttm):
         tt = target_type.upper()
diff --git a/superset/sql_lab.py b/superset/sql_lab.py
index 4b0bd863bc..638b29abbe 100644
--- a/superset/sql_lab.py
+++ b/superset/sql_lab.py
@@ -154,7 +154,6 @@ def execute_sql(ctask, query_id, return_results=True, store_results=False):
         template_processor = get_template_processor(
             database=database, query=query)
         executed_sql = template_processor.process_template(executed_sql)
-        executed_sql = db_engine_spec.sql_preprocessor(executed_sql)
     except Exception as e:
         logging.exception(e)
         msg = "Template rendering failed: " + utils.error_msg_from_exception(e)