diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/CheckAnalysis.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/CheckAnalysis.scala
index 26d26385904f6..db417526ed5b9 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/CheckAnalysis.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/CheckAnalysis.scala
@@ -306,7 +306,7 @@ trait CheckAnalysis extends PredicateHelper {
               // Check if the data types match.
               dataTypes(child).zip(ref).zipWithIndex.foreach { case ((dt1, dt2), ci) =>
                 // SPARK-18058: we shall not care about the nullability of columns
-                if (dt1.asNullable != dt2.asNullable) {
+                if (!dt1.sameType(dt2)) {
                   failAnalysis(
                     s"""
                       |${operator.nodeName} can only be performed on tables with the compatible
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/conditionalExpressions.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/conditionalExpressions.scala
index a7d9e2dfcdb62..afc190e6978d4 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/conditionalExpressions.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/conditionalExpressions.scala
@@ -41,7 +41,7 @@ case class If(predicate: Expression, trueValue: Expression, falseValue: Expressi
     if (predicate.dataType != BooleanType) {
       TypeCheckResult.TypeCheckFailure(
         s"type of predicate expression in If should be boolean, not ${predicate.dataType}")
-    } else if (trueValue.dataType.asNullable != falseValue.dataType.asNullable) {
+    } else if (!trueValue.dataType.sameType(falseValue.dataType)) {
       TypeCheckResult.TypeCheckFailure(s"differing types in '$sql' " +
         s"(${trueValue.dataType.simpleString} and ${falseValue.dataType.simpleString}).")
     } else {
diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicLogicalOperators.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicLogicalOperators.scala
index 4e333d57f3623..7aaefc8529a5f 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicLogicalOperators.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicLogicalOperators.scala
@@ -134,7 +134,7 @@ abstract class SetOperation(left: LogicalPlan, right: LogicalPlan) extends Binar
     childrenResolved &&
       left.output.length == right.output.length &&
       left.output.zip(right.output).forall { case (l, r) =>
-        l.dataType.asNullable == r.dataType.asNullable
+        l.dataType.sameType(r.dataType)
       } && duplicateResolved
 }
 
@@ -211,8 +211,8 @@ case class Union(children: Seq[LogicalPlan]) extends LogicalPlan {
         child.output.length == children.head.output.length &&
         // compare the data types with the first child
         child.output.zip(children.head.output).forall {
-          case (l, r) => l.dataType.asNullable == r.dataType.asNullable }
-      )
+          case (l, r) => l.dataType.sameType(r.dataType)
+        })
     children.length > 1 && childrenResolved && allChildrenCompatible
   }
 
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala
index e81512d1abf84..68c52177ff70c 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/DataSourceStrategy.scala
@@ -163,7 +163,7 @@ case class DataSourceAnalysis(conf: CatalystConf) extends Rule[LogicalPlan] {
 
     case i @ logical.InsertIntoTable(
            l @ LogicalRelation(t: HadoopFsRelation, _, table), part, query, overwrite, false)
-        if query.resolved && t.schema.asNullable == query.schema.asNullable =>
+        if query.resolved && t.schema.sameType(query.schema) =>
 
       // Sanity checks
       if (t.location.rootPaths.size != 1) {