Merge remote-tracking branch 'upstream/master' into SPARK-33884

# Conflicts:
#	sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/PushFoldableIntoBranchesSuite.scala
#	sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SimplifyConditionalSuite.scala

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/PushFoldableIntoBranchesSuite.scala

@@ -259,6 +259,17 @@ class PushFoldableIntoBranchesSuite
       CaseWhen(Seq((a, FalseLiteral), (c, FalseLiteral)), None))
   }
 
+  test("SPARK-33847: Remove the CaseWhen if elseValue is empty and other outputs are null") {
+    Seq(a, LessThan(Rand(1), Literal(0.5))).foreach { condition =>
+      assertEquivalent(
+        EqualTo(CaseWhen(Seq((condition, Literal.create(null, IntegerType)))), Literal(2)),
+        Literal.create(null, BooleanType))
+      assertEquivalent(
+        EqualTo(CaseWhen(Seq((condition, Literal("str")))).cast(IntegerType), Literal(2)),
+        Literal.create(null, BooleanType))
+    }
+  }
+
   test("SPARK-33884: simplify CaseWhen when one clause is null and another is boolean") {
     val p = IsNull('a)
     val nullLiteral = Literal(null, BooleanType)

sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/optimizer/SimplifyConditionalSuite.scala

@@ -216,6 +216,14 @@ class SimplifyConditionalSuite extends PlanTest with ExpressionEvalHelper with P
       LessThanOrEqual(Rand(0), UnresolvedAttribute("a")))
   }
 
+  test("SPARK-33847: Remove the CaseWhen if elseValue is empty and other outputs are null") {
+    Seq(GreaterThan('a, 1), GreaterThan(Rand(0), 1)).foreach { condition =>
+      assertEquivalent(
+        CaseWhen((condition, Literal.create(null, IntegerType)) :: Nil, None),
+        Literal.create(null, IntegerType))
+    }
+  }
+
   test("SPARK-33884: simplify CaseWhen when one clause is null and another is boolean") {
     val p = IsNull('a)
     val nullLiteral = Literal(null, BooleanType)