diff --git a/dialect_mysql.go b/dialect_mysql.go
index 51b1926a..10d63db2 100644
--- a/dialect_mysql.go
+++ b/dialect_mysql.go
@@ -61,7 +61,11 @@ func (mysql) DataTypeOf(field *StructField) string {
 			}
 		case reflect.Struct:
 			if _, ok := dataValue.Interface().(time.Time); ok {
-				sqlType = "timestamp NULL"
+				if _, ok := field.TagSettings["NOT NULL"]; ok {
+					sqlType = "timestamp"
+				} else {
+					sqlType = "timestamp NULL"
+				}
 			}
 		default:
 			if _, ok := dataValue.Interface().([]byte); ok {
diff --git a/structs_test.go b/structs_test.go
index 42eb6bc3..e7bae25f 100644
--- a/structs_test.go
+++ b/structs_test.go
@@ -42,7 +42,7 @@ type CreditCard struct {
 	ID        int8
 	Number    string
 	UserId    sql.NullInt64
-	CreatedAt time.Time
+	CreatedAt time.Time `sql:"not null"`
 	UpdatedAt time.Time
 	DeletedAt *time.Time
 }