diff --git a/CHANGELOG.md b/CHANGELOG.md
index b99e87b..a578397 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # CHANGELOG
 
+## v0.2.12
+
+- Fix where the undefined operation type is generated https://github.com/mununki/gqlmerge/pull/47
+
 ## v0.2.11
 
 - Fixed mis-used rune `[` instead of tokLBracket https://github.com/mununki/gqlmerge/pull/41
diff --git a/command/command.go b/command/command.go
index 1714627..a94ac50 100644
--- a/command/command.go
+++ b/command/command.go
@@ -32,7 +32,7 @@ func (c *Command) Check() error {
 		NotEnoughArgs:    "❌ Not enough arguments",
 		OutputFileNeeded: "❌ Output file argument is needed",
 		WrongOption:      "❌ Wrong options",
-		Version:          "v0.2.11",
+		Version:          "v0.2.12",
 	}
 
 	help := flag.Bool("h", false, "show the help")
diff --git a/lib/write.go b/lib/write.go
index 27c3ab5..8d11ca8 100644
--- a/lib/write.go
+++ b/lib/write.go
@@ -10,28 +10,25 @@ type MergedSchema struct {
 }
 
 func (ms *MergedSchema) WriteSchema(s *Schema) string {
-	ms.writeDescriptions(s.SchemaDefinitions[0].Descriptions, 0, true)
-	ms.buf.WriteString("schema {\n")
-	ms.addIndent(1)
-	if s.SchemaDefinitions[0].Query != nil {
-		ms.buf.WriteString("query: " + *s.SchemaDefinitions[0].Query + "\n")
-	} else {
-		ms.buf.WriteString("query: Query\n")
-	}
-	ms.addIndent(1)
-	if s.SchemaDefinitions[0].Mutation != nil {
-		ms.buf.WriteString("mutation: " + *s.SchemaDefinitions[0].Mutation + "\n")
-	} else {
-		ms.buf.WriteString("mutation: Mutation\n")
-	}
-	ms.addIndent(1)
-	if s.SchemaDefinitions[0].Subscription != nil {
-		ms.buf.WriteString("subscription: " + *s.SchemaDefinitions[0].Subscription + "\n")
-	} else {
-		ms.buf.WriteString("subscription: Subscription\n")
-	}
+	if (s.SchemaDefinitions[0].Query != nil) || (s.SchemaDefinitions[0].Mutation != nil) || (s.SchemaDefinitions[0].Subscription != nil) {
+		ms.writeDescriptions(s.SchemaDefinitions[0].Descriptions, 0, true)
+		ms.buf.WriteString("schema {\n")
+		ms.addIndent(1)
 
-	ms.buf.WriteString("}\n\n")
+		if s.SchemaDefinitions[0].Query != nil {
+			ms.buf.WriteString("query: " + *s.SchemaDefinitions[0].Query + "\n")
+		}
+		ms.addIndent(1)
+		if s.SchemaDefinitions[0].Mutation != nil {
+			ms.buf.WriteString("mutation: " + *s.SchemaDefinitions[0].Mutation + "\n")
+		}
+		ms.addIndent(1)
+		if s.SchemaDefinitions[0].Subscription != nil {
+			ms.buf.WriteString("subscription: " + *s.SchemaDefinitions[0].Subscription + "\n")
+		}
+
+		ms.buf.WriteString("}\n\n")
+	}
 
 	numOfDirs := len(s.DirectiveDefinitions)
 	if numOfDirs > 0 {
diff --git a/test/arg_input/generated.graphql b/test/arg_input/generated.graphql
index eb4764c..a768ee2 100644
--- a/test/arg_input/generated.graphql
+++ b/test/arg_input/generated.graphql
@@ -1,8 +1,6 @@
 schema {
-    query: Query
-    mutation: Mutation
-    subscription: Subscription
-}
+        mutation: Mutation
+    }
 
 type Mutation {
     createLogKo(input: CreateLogInput!): String!
diff --git a/test/basic/generated.graphql b/test/basic/generated.graphql
index 4681131..c74f761 100644
--- a/test/basic/generated.graphql
+++ b/test/basic/generated.graphql
@@ -2,8 +2,7 @@
 schema {
     query: Query
     mutation: Mutation
-    subscription: Subscription
-}
+    }
 
 """
 TEST : Directive 1
diff --git a/test/property_type/generated.graphql b/test/property_type/generated.graphql
index 4254040..985822a 100644
--- a/test/property_type/generated.graphql
+++ b/test/property_type/generated.graphql
@@ -1,9 +1,3 @@
-schema {
-    query: Query
-    mutation: Mutation
-    subscription: Subscription
-}
-
 type SomePayload {
     type: String!
     someKey: String!