From 05be86611785fef2904992e4e7d31dce23f1c51b Mon Sep 17 00:00:00 2001
From: John Bodley <4567245+john-bodley@users.noreply.github.com>
Date: Wed, 13 Mar 2019 13:22:28 -0700
Subject: [PATCH] [db-engine-spec] Aligning Hive/Presto partition logic (#7007)

---
 superset/db_engine_specs.py | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/superset/db_engine_specs.py b/superset/db_engine_specs.py
index 64bffe75bc38..c738c9f3ab4b 100644
--- a/superset/db_engine_specs.py
+++ b/superset/db_engine_specs.py
@@ -986,16 +986,16 @@ def where_latest_partition(
         except Exception:
             # table is not partitioned
             return False
-        for c in columns:
-            if c.get('name') == col_name:
-                return qry.where(Column(col_name) == value)
+        if value is not None:
+            for c in columns:
+                if c.get('name') == col_name:
+                    return qry.where(Column(col_name) == value)
         return False
 
     @classmethod
     def _latest_partition_from_df(cls, df):
-        recs = df.to_records(index=False)
-        if recs:
-            return recs[0][0]
+        if not df.empty:
+            return df.to_records(index=False)[0][0]
 
     @classmethod
     def latest_partition(cls, table_name, schema, database, show_first=False):
@@ -1012,7 +1012,7 @@ def latest_partition(cls, table_name, schema, database, show_first=False):
         :type show_first: bool
 
         >>> latest_partition('foo_table')
-        '2018-01-01'
+        ('ds', '2018-01-01')
         """
         indexes = database.get_indexes(table_name, schema)
         if len(indexes[0]['column_names']) < 1:
@@ -1330,9 +1330,10 @@ def where_latest_partition(
         except Exception:
             # table is not partitioned
             return False
-        for c in columns:
-            if c.get('name') == col_name:
-                return qry.where(Column(col_name) == value)
+        if value is not None:
+            for c in columns:
+                if c.get('name') == col_name:
+                    return qry.where(Column(col_name) == value)
         return False
 
     @classmethod
@@ -1343,7 +1344,8 @@ def latest_sub_partition(cls, table_name, schema, database, **kwargs):
     @classmethod
     def _latest_partition_from_df(cls, df):
         """Hive partitions look like ds={partition name}"""
-        return df.ix[:, 0].max().split('=')[1]
+        if not df.empty:
+            return df.ix[:, 0].max().split('=')[1]
 
     @classmethod
     def _partition_query(