From 11c62ca2050c0d6003a512e7b11a2994a531f370 Mon Sep 17 00:00:00 2001
From: Blottiere Paul <blottiere.paul@gmail.com>
Date: Tue, 22 Aug 2017 11:07:26 +0100
Subject: [PATCH] A joined feature is added only when one of its field is not
 null

---
 src/core/qgsvectorlayer.cpp | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/core/qgsvectorlayer.cpp b/src/core/qgsvectorlayer.cpp
index a2f6f139a62..7a196b4607f 100644
--- a/src/core/qgsvectorlayer.cpp
+++ b/src/core/qgsvectorlayer.cpp
@@ -2718,7 +2718,24 @@ bool QgsVectorLayer::addFeaturesToJoinedLayers( QgsFeatureList &features, Flags
           joinLayer->updateFeature( existingFeature );
         }
         else
-          joinFeatures << joinFeature;
+        {
+          // joined feature is added only if one of its field is not null
+          bool notNullFields = false;
+          Q_FOREACH ( const QgsField &field, joinFeature.fields() )
+          {
+            if ( field.name() == info.joinFieldName() )
+              continue;
+
+            if ( !joinFeature.attribute( field.name() ).isNull() )
+            {
+              notNullFields = true;
+              break;
+            }
+          }
+
+          if ( notNullFields )
+            joinFeatures << joinFeature;
+        }
       }
 
       joinLayer->addFeatures( joinFeatures );