diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/types/StructType.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/types/StructType.scala
index 83ee1913da..c9862cb629 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/types/StructType.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/types/StructType.scala
@@ -653,6 +653,12 @@ object StructType extends AbstractDataType {
       case (leftUdt: UserDefinedType[_], rightUdt: UserDefinedType[_])
         if leftUdt.userClass == rightUdt.userClass => leftUdt
 
+      case (YearMonthIntervalType(lstart, lend), YearMonthIntervalType(rstart, rend)) =>
+        YearMonthIntervalType(Math.min(lstart, rstart).toByte, Math.max(lend, rend).toByte)
+
+      case (DayTimeIntervalType(lstart, lend), DayTimeIntervalType(rstart, rend)) =>
+        DayTimeIntervalType(Math.min(lstart, rstart).toByte, Math.max(lend, rend).toByte)
+
       case (leftType, rightType) if leftType == rightType =>
         leftType
 
diff --git a/sql/catalyst/src/test/scala/org/apache/spark/sql/types/StructTypeSuite.scala b/sql/catalyst/src/test/scala/org/apache/spark/sql/types/StructTypeSuite.scala
index 8db3831392..8cc04c78d8 100644
--- a/sql/catalyst/src/test/scala/org/apache/spark/sql/types/StructTypeSuite.scala
+++ b/sql/catalyst/src/test/scala/org/apache/spark/sql/types/StructTypeSuite.scala
@@ -25,7 +25,9 @@ import org.apache.spark.sql.catalyst.plans.SQLHelper
 import org.apache.spark.sql.internal.SQLConf
 import org.apache.spark.sql.types.{DayTimeIntervalType => DT}
 import org.apache.spark.sql.types.{YearMonthIntervalType => YM}
+import org.apache.spark.sql.types.DayTimeIntervalType._
 import org.apache.spark.sql.types.StructType.fromDDL
+import org.apache.spark.sql.types.YearMonthIntervalType._
 
 class StructTypeSuite extends SparkFunSuite with SQLHelper {
 
@@ -382,4 +384,25 @@ class StructTypeSuite extends SparkFunSuite with SQLHelper {
     assert(e.getMessage.contains(
       "Field name a2.element.C.name is invalid: a2.element.c is not a struct"))
   }
+
+  test("SPARK-36807: Merge ANSI interval types to a tightest common type") {
+    Seq(
+      (YM(YEAR), YM(YEAR)) -> YM(YEAR),
+      (YM(YEAR), YM(MONTH)) -> YM(YEAR, MONTH),
+      (YM(MONTH), YM(MONTH)) -> YM(MONTH),
+      (YM(YEAR, MONTH), YM(YEAR)) -> YM(YEAR, MONTH),
+      (YM(YEAR, MONTH), YM(YEAR, MONTH)) -> YM(YEAR, MONTH),
+      (DT(DAY), DT(DAY)) -> DT(DAY),
+      (DT(SECOND), DT(SECOND)) -> DT(SECOND),
+      (DT(DAY), DT(SECOND)) -> DT(DAY, SECOND),
+      (DT(HOUR, SECOND), DT(DAY, MINUTE)) -> DT(DAY, SECOND),
+      (DT(HOUR, MINUTE), DT(DAY, SECOND)) -> DT(DAY, SECOND)
+    ).foreach { case ((i1, i2), expected) =>
+      val st1 = new StructType().add("interval", i1)
+      val st2 = new StructType().add("interval", i2)
+      val expectedStruct = new StructType().add("interval", expected)
+      assert(st1.merge(st2) === expectedStruct)
+      assert(st2.merge(st1) === expectedStruct)
+    }
+  }
 }