diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala
index 3ffd9f9d88750..f47391c049298 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/EquivalentExpressions.scala
@@ -40,7 +40,11 @@ class EquivalentExpressions {
    * Returns true if there was already a matching expression.
    */
   def addExpr(expr: Expression): Boolean = {
-    updateExprInMap(expr, equivalenceMap)
+    if (supportedExpression(expr)) {
+      updateExprInMap(expr, equivalenceMap)
+    } else {
+      false
+    }
   }
 
   /**
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/SubexpressionEliminationSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/SubexpressionEliminationSuite.scala
index b16629f59aa2d..44d8ea3a112e1 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/SubexpressionEliminationSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/catalyst/expressions/SubexpressionEliminationSuite.scala
@@ -21,7 +21,7 @@ import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.codegen._
 import org.apache.spark.sql.catalyst.plans.logical.LocalRelation
 import org.apache.spark.sql.internal.SQLConf
-import org.apache.spark.sql.types.{BinaryType, DataType, IntegerType}
+import org.apache.spark.sql.types.{BinaryType, DataType, IntegerType, ObjectType}
 
 class SubexpressionEliminationSuite extends SparkFunSuite with ExpressionEvalHelper {
   test("Semantic equals and hash") {
@@ -449,6 +449,22 @@ class SubexpressionEliminationSuite extends SparkFunSuite with ExpressionEvalHel
     assert(e2.getCommonSubexpressions.size == 1)
     assert(e2.getCommonSubexpressions.head == add)
   }
+
+  test("SPARK-42851: Handle supportExpression consistently across add and get") {
+    val expr = {
+      val function = (lambda: Expression) => Add(lambda, Literal(1))
+      val elementType = IntegerType
+      val colClass = classOf[Array[Int]]
+      val inputType = ObjectType(colClass)
+      val inputObject = BoundReference(0, inputType, nullable = true)
+      objects.MapObjects(function, inputObject, elementType, true, Option(colClass))
+    }
+    val equivalence = new EquivalentExpressions
+    equivalence.addExpr(expr)
+    val hasMatching = equivalence.addExpr(expr)
+    val cseState = equivalence.getExprState(expr)
+    assert(hasMatching == cseState.isDefined)
+  }
 }
 
 case class CodegenFallbackExpression(child: Expression)
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala
index 737d31cc6e913..2ba9039166f48 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameAggregateSuite.scala
@@ -1538,6 +1538,13 @@ class DataFrameAggregateSuite extends QueryTest
     )
     checkAnswer(res, Row(1, 1, 1) :: Row(4, 1, 2) :: Nil)
   }
+
+  test("SPARK-42851: common subexpression should consistently handle aggregate and result exprs") {
+    val res = sql(
+      "select max(transform(array(id), x -> x)), max(transform(array(id), x -> x)) from range(2)"
+    )
+    checkAnswer(res, Row(Array(1), Array(1)))
+  }
 }
 
 case class B(c: Option[Double])