[SPARK-12231][SQL]create a combineFilters' projection when we call buildPartitionedTableScan

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala

@@ -85,9 +85,12 @@ private[sql] object DataSourceStrategy extends Strategy with Logging {
         s"Selected $selected partitions out of $total, pruned $percentPruned% partitions."
       }
 
+      // need to add projections from combineFilters in
+      val combineProjections =
+        projects.toSet.union(combineFilters.flatMap(_.references).toSet).toSeq
       val scan = buildPartitionedTableScan(
         l,
-        projects,
+        combineProjections,
         pushedFilters,
         t.partitionSpec.partitionColumns,
         selectedPartitions)

sql/core/src/test/scala/org/apache/spark/sql/DataFrameNaFunctionsSuite.scala

@@ -194,4 +194,31 @@ class DataFrameNaFunctionsSuite extends QueryTest with SharedSQLContext {
     assert(out1(4) === Row("Amy", null, null))
     assert(out1(5) === Row(null, null, null))
   }
+
+  test("dropna with partitionBy and groupBy") {
+    withTempPath { dir =>
+      val df = sqlContext.range(10)
+      val df1 = df.withColumn("a", $"id".cast("int"))
+      df1.write.partitionBy("id").parquet(dir.getCanonicalPath)
+
+      val df2 = sqlContext.read.parquet(dir.getCanonicalPath)
+
+      val group = df2.na.drop().groupBy().count()
+      group.collect()
+    }
+  }
+
+  test("dropna with partitionBy") {
+    withTempPath { dir =>
+      val df = sqlContext.range(10)
+      val df1 = df.withColumn("a", $"id".cast("int"))
+      df1.write.partitionBy("id").parquet(dir.getCanonicalPath)
+
+      val df2 = sqlContext.read.parquet(dir.getCanonicalPath)
+
+      val group = df2.na.drop().count()
+
+    }
+  }
+
 }