diff --git a/dbms/src/Analyzers/AnalyzeColumns.cpp b/dbms/src/Analyzers/AnalyzeColumns.cpp
index 73760c4ff01..93b43157664 100644
--- a/dbms/src/Analyzers/AnalyzeColumns.cpp
+++ b/dbms/src/Analyzers/AnalyzeColumns.cpp
@@ -135,7 +135,7 @@ ASTPtr createASTIdentifierForColumnInTable(const String & column, const CollectT
 {
     ASTPtr database_name_identifier_node;
     if (!table.database_name.empty())
-        database_name_identifier_node =  std::make_shared<ASTIdentifier>(table.database_name, ASTIdentifier::Column);
+        database_name_identifier_node = std::make_shared<ASTIdentifier>(table.database_name);
 
     ASTPtr table_name_identifier_node;
     String table_name_or_alias;
@@ -146,9 +146,9 @@ ASTPtr createASTIdentifierForColumnInTable(const String & column, const CollectT
         table_name_or_alias = table.alias;
 
     if (!table_name_or_alias.empty())
-        table_name_identifier_node = std::make_shared<ASTIdentifier>(table_name_or_alias, ASTIdentifier::Column);
+        table_name_identifier_node = std::make_shared<ASTIdentifier>(table_name_or_alias);
 
-    ASTPtr column_identifier_node = std::make_shared<ASTIdentifier>(column, ASTIdentifier::Column);
+    ASTPtr column_identifier_node = std::make_shared<ASTIdentifier>(column);
 
     String compound_name;
     if (database_name_identifier_node)
@@ -157,7 +157,7 @@ ASTPtr createASTIdentifierForColumnInTable(const String & column, const CollectT
         compound_name += table_name_or_alias + ".";
     compound_name += column;
 
-    auto elem = std::make_shared<ASTIdentifier>(compound_name, ASTIdentifier::Column);
+    auto elem = std::make_shared<ASTIdentifier>(compound_name);
 
     if (database_name_identifier_node)
         elem->children.emplace_back(std::move(database_name_identifier_node));
diff --git a/dbms/src/Interpreters/ExpressionAnalyzer.cpp b/dbms/src/Interpreters/ExpressionAnalyzer.cpp
index 743e0835096..7d59b50798a 100644
--- a/dbms/src/Interpreters/ExpressionAnalyzer.cpp
+++ b/dbms/src/Interpreters/ExpressionAnalyzer.cpp
@@ -308,7 +308,7 @@ void ExpressionAnalyzer::translateQualifiedNamesImpl(ASTPtr & ast, const std::ve
 {
     if (auto * identifier = typeid_cast<ASTIdentifier *>(ast.get()))
     {
-        if (identifier->kind == ASTIdentifier::Column)
+        if (identifier->general())
         {
             /// Select first table name with max number of qualifiers which can be stripped.
             size_t max_num_qualifiers_to_strip = 0;
@@ -646,7 +646,7 @@ void ExpressionAnalyzer::findExternalTables(ASTPtr & ast)
     StoragePtr external_storage;
 
     if (ASTIdentifier * node = typeid_cast<ASTIdentifier *>(ast.get()))
-        if (node->kind == ASTIdentifier::Table)
+        if (node->special())
             if ((external_storage = context.tryGetExternalTable(node->name)))
                 external_tables[node->name] = external_storage;
 }
@@ -830,7 +830,7 @@ void ExpressionAnalyzer::addExternalStorage(ASTPtr & subquery_or_table_name_or_t
         *  instead of doing a subquery, you just need to read it.
         */
 
-    auto database_and_table_name = std::make_shared<ASTIdentifier>(external_table_name, ASTIdentifier::Table);
+    auto database_and_table_name = ASTIdentifier::createSpecial(external_table_name);
 
     if (auto ast_table_expr = typeid_cast<ASTTableExpression *>(subquery_or_table_name_or_table_expression.get()))
     {
@@ -1659,7 +1659,7 @@ void ExpressionAnalyzer::getArrayJoinedColumnsImpl(const ASTPtr & ast)
 
     if (ASTIdentifier * node = typeid_cast<ASTIdentifier *>(ast.get()))
     {
-        if (node->kind == ASTIdentifier::Column)
+        if (node->general())
         {
             auto splitted = Nested::splitName(node->name);  /// ParsedParams, Key1
 
@@ -2884,7 +2884,7 @@ void ExpressionAnalyzer::collectJoinedColumnsFromJoinOnExpr()
         auto * identifier = typeid_cast<const ASTIdentifier *>(ast.get());
         if (identifier)
         {
-            if (identifier->kind == ASTIdentifier::Column)
+            if (identifier->general())
             {
                 auto left_num_components = getNumComponentsToStripInOrderToTranslateQualifiedName(*identifier, left_source_names);
                 auto right_num_components = getNumComponentsToStripInOrderToTranslateQualifiedName(*identifier, right_source_names);
@@ -2923,7 +2923,7 @@ void ExpressionAnalyzer::collectJoinedColumnsFromJoinOnExpr()
         auto * identifier = typeid_cast<const ASTIdentifier *>(ast.get());
         if (identifier)
         {
-            if (identifier->kind == ASTIdentifier::Column)
+            if (identifier->general())
             {
                 auto num_components = getNumComponentsToStripInOrderToTranslateQualifiedName(*identifier, source_names);
                 stripIdentifier(ast, num_components);
@@ -3091,7 +3091,7 @@ void ExpressionAnalyzer::getRequiredSourceColumnsImpl(const ASTPtr & ast,
 
     if (ASTIdentifier * node = typeid_cast<ASTIdentifier *>(ast.get()))
     {
-        if (node->kind == ASTIdentifier::Column
+        if (node->general()
             && !ignored_names.count(node->name)
             && !ignored_names.count(Nested::extractTableName(node->name)))
         {
diff --git a/dbms/src/Interpreters/InJoinSubqueriesPreprocessor.cpp b/dbms/src/Interpreters/InJoinSubqueriesPreprocessor.cpp
index 9df80de4c2f..45105594c4f 100644
--- a/dbms/src/Interpreters/InJoinSubqueriesPreprocessor.cpp
+++ b/dbms/src/Interpreters/InJoinSubqueriesPreprocessor.cpp
@@ -102,18 +102,18 @@ StoragePtr tryGetTable(const ASTPtr & database_and_table, const Context & contex
 
 void replaceDatabaseAndTable(ASTPtr & database_and_table, const String & database_name, const String & table_name)
 {
-    ASTPtr table = std::make_shared<ASTIdentifier>(table_name, ASTIdentifier::Table);
+    ASTPtr table = ASTIdentifier::createSpecial(table_name);
 
     if (!database_name.empty())
     {
-        ASTPtr database = std::make_shared<ASTIdentifier>(database_name, ASTIdentifier::Database);
+        ASTPtr database = ASTIdentifier::createSpecial(database_name);
 
-        database_and_table = std::make_shared<ASTIdentifier>(database_name + "." + table_name, ASTIdentifier::Table);
+        database_and_table = ASTIdentifier::createSpecial(database_name + "." + table_name);
         database_and_table->children = {database, table};
     }
     else
     {
-        database_and_table = std::make_shared<ASTIdentifier>(table_name, ASTIdentifier::Table);
+        database_and_table = ASTIdentifier::createSpecial(table_name);
     }
 }
 
diff --git a/dbms/src/Interpreters/QueryNormalizer.cpp b/dbms/src/Interpreters/QueryNormalizer.cpp
index e7785600114..701f140b306 100644
--- a/dbms/src/Interpreters/QueryNormalizer.cpp
+++ b/dbms/src/Interpreters/QueryNormalizer.cpp
@@ -85,7 +85,7 @@ void QueryNormalizer::performImpl(ASTPtr & ast, MapOfASTs & finished_asts, SetOf
         if (functionIsInOrGlobalInOperator(func_node->name))
             if (ASTIdentifier * right = typeid_cast<ASTIdentifier *>(func_node->arguments->children.at(1).get()))
                 if (!aliases.count(right->name))
-                    right->kind = ASTIdentifier::Table;
+                    right->setSpecial();
 
         /// Special cases for count function.
         String func_name_lowercase = Poco::toLower(func_node->name);
@@ -108,7 +108,7 @@ void QueryNormalizer::performImpl(ASTPtr & ast, MapOfASTs & finished_asts, SetOf
     }
     else if ((identifier_node = typeid_cast<ASTIdentifier *>(ast.get())))
     {
-        if (identifier_node->kind == ASTIdentifier::Column)
+        if (identifier_node->general())
         {
             /// If it is an alias, but not a parent alias (for constructs like "SELECT column + 1 AS column").
             auto it_alias = aliases.find(identifier_node->name);
@@ -122,7 +122,7 @@ void QueryNormalizer::performImpl(ASTPtr & ast, MapOfASTs & finished_asts, SetOf
                 {
                     /// Avoid infinite recursion here
                     auto replace_to_identifier = typeid_cast<ASTIdentifier *>(it_alias->second.get());
-                    bool is_cycle = replace_to_identifier && replace_to_identifier->kind == ASTIdentifier::Column
+                    bool is_cycle = replace_to_identifier && replace_to_identifier->general()
                         && replace_to_identifier->name == identifier_node->name;
 
                     if (!is_cycle)
@@ -164,9 +164,7 @@ void QueryNormalizer::performImpl(ASTPtr & ast, MapOfASTs & finished_asts, SetOf
             if (database_and_table_name)
             {
                 if (ASTIdentifier * right = typeid_cast<ASTIdentifier *>(database_and_table_name.get()))
-                {
-                    right->kind = ASTIdentifier::Table;
-                }
+                    right->setSpecial();
             }
         }
     }
diff --git a/dbms/src/Parsers/ASTIdentifier.h b/dbms/src/Parsers/ASTIdentifier.h
index 1ef06711505..0ada2b60852 100644
--- a/dbms/src/Parsers/ASTIdentifier.h
+++ b/dbms/src/Parsers/ASTIdentifier.h
@@ -10,22 +10,17 @@ namespace DB
   */
 class ASTIdentifier : public ASTWithAlias
 {
-public:
     enum Kind    /// TODO This is semantic, not syntax. Remove it.
     {
-        Column,
-        Database,
-        Table,
-        Format,
+        General,
+        Special, // Database, Table, Format
     };
 
+public:
     /// name. The composite identifier here will have a concatenated name (of the form a.b.c), and individual components will be available inside the children.
     String name;
 
-    /// what this identifier identifies
-    Kind kind;
-
-    ASTIdentifier(const String & name_, const Kind kind_ = Column)
+    ASTIdentifier(const String & name_, const Kind kind_ = General)
         : name(name_), kind(kind_) { range = StringRange(name.data(), name.data() + name.size()); }
 
     /** Get the text that identifies this element. */
@@ -38,9 +33,21 @@ public:
         set.insert(name);
     }
 
+    void setSpecial() { kind = Special; }
+    bool general() const { return kind == General; }
+    bool special() const { return kind == Special; }
+
+    static std::shared_ptr<ASTIdentifier> createSpecial(const String & name_)
+    {
+        return std::make_shared<ASTIdentifier>(name_, ASTIdentifier::Special);
+    }
+
 protected:
     void formatImplWithoutAlias(const FormatSettings & settings, FormatState & state, FormatStateStacked frame) const override;
     void appendColumnNameImpl(WriteBuffer & ostr) const override;
+
+private:
+    Kind kind;
 };
 
 }
diff --git a/dbms/src/Parsers/ASTSelectQuery.cpp b/dbms/src/Parsers/ASTSelectQuery.cpp
index 0e48ac585b7..429f5cbeb0e 100644
--- a/dbms/src/Parsers/ASTSelectQuery.cpp
+++ b/dbms/src/Parsers/ASTSelectQuery.cpp
@@ -345,11 +345,11 @@ void ASTSelectQuery::setDatabaseIfNeeded(const String & database_name)
 
     if (table_expression->database_and_table_name->children.empty())
     {
-        ASTPtr database = std::make_shared<ASTIdentifier>(database_name, ASTIdentifier::Database);
+        ASTPtr database = ASTIdentifier::createSpecial(database_name);
         ASTPtr table = table_expression->database_and_table_name;
 
         const String & old_name = static_cast<ASTIdentifier &>(*table_expression->database_and_table_name).name;
-        table_expression->database_and_table_name = std::make_shared<ASTIdentifier>(database_name + "." + old_name, ASTIdentifier::Table);
+        table_expression->database_and_table_name = ASTIdentifier::createSpecial(database_name + "." + old_name);
         table_expression->database_and_table_name->children = {database, table};
     }
     else if (table_expression->database_and_table_name->children.size() != 2)
@@ -376,18 +376,18 @@ void ASTSelectQuery::replaceDatabaseAndTable(const String & database_name, const
         table_expression = table_expr.get();
     }
 
-    ASTPtr table = std::make_shared<ASTIdentifier>(table_name, ASTIdentifier::Table);
+    ASTPtr table = ASTIdentifier::createSpecial(table_name);
 
     if (!database_name.empty())
     {
-        ASTPtr database = std::make_shared<ASTIdentifier>(database_name, ASTIdentifier::Database);
+        ASTPtr database = ASTIdentifier::createSpecial(database_name);
 
-        table_expression->database_and_table_name = std::make_shared<ASTIdentifier>(database_name + "." + table_name, ASTIdentifier::Table);
+        table_expression->database_and_table_name = ASTIdentifier::createSpecial(database_name + "." + table_name);
         table_expression->database_and_table_name->children = {database, table};
     }
     else
     {
-        table_expression->database_and_table_name = std::make_shared<ASTIdentifier>(table_name, ASTIdentifier::Table);
+        table_expression->database_and_table_name = ASTIdentifier::createSpecial(table_name);
     }
 }
 
diff --git a/dbms/src/Parsers/ParserQueryWithOutput.cpp b/dbms/src/Parsers/ParserQueryWithOutput.cpp
index 3ec71de5f0c..7c2b6afc442 100644
--- a/dbms/src/Parsers/ParserQueryWithOutput.cpp
+++ b/dbms/src/Parsers/ParserQueryWithOutput.cpp
@@ -69,7 +69,7 @@ bool ParserQueryWithOutput::parseImpl(Pos & pos, ASTPtr & node, Expected & expec
 
         if (!format_p.parse(pos, query_with_output.format, expected))
             return false;
-        typeid_cast<ASTIdentifier &>(*(query_with_output.format)).kind = ASTIdentifier::Format;
+        typeid_cast<ASTIdentifier &>(*(query_with_output.format)).setSpecial();
 
         query_with_output.children.push_back(query_with_output.format);
     }
diff --git a/dbms/src/Storages/MergeTree/MergeTreeWhereOptimizer.cpp b/dbms/src/Storages/MergeTree/MergeTreeWhereOptimizer.cpp
index 36dba0719f4..998084381cb 100644
--- a/dbms/src/Storages/MergeTree/MergeTreeWhereOptimizer.cpp
+++ b/dbms/src/Storages/MergeTree/MergeTreeWhereOptimizer.cpp
@@ -384,7 +384,7 @@ bool MergeTreeWhereOptimizer::cannotBeMoved(const IAST * ptr) const
     else if (const auto identifier_ptr = typeid_cast<const ASTIdentifier *>(ptr))
     {
         /// disallow moving result of ARRAY JOIN to PREWHERE
-        if (identifier_ptr->kind == ASTIdentifier::Column)
+        if (identifier_ptr->general())
             if (array_joined_names.count(identifier_ptr->name) ||
                 array_joined_names.count(Nested::extractTableName(identifier_ptr->name)))
                 return true;
diff --git a/dbms/src/Storages/StorageBuffer.cpp b/dbms/src/Storages/StorageBuffer.cpp
index c641cbc915b..4ec32883e6b 100644
--- a/dbms/src/Storages/StorageBuffer.cpp
+++ b/dbms/src/Storages/StorageBuffer.cpp
@@ -595,7 +595,7 @@ void StorageBuffer::writeBlockToDestination(const Block & block, StoragePtr tabl
     insert->columns = list_of_columns;
     list_of_columns->children.reserve(columns_intersection.size());
     for (const String & column : columns_intersection)
-        list_of_columns->children.push_back(std::make_shared<ASTIdentifier>(column, ASTIdentifier::Column));
+        list_of_columns->children.push_back(std::make_shared<ASTIdentifier>(column));
 
     InterpreterInsertQuery interpreter{insert, context, allow_materialized};
 
diff --git a/dbms/src/Storages/VirtualColumnUtils.cpp b/dbms/src/Storages/VirtualColumnUtils.cpp
index 04b5ee405bf..71e26c323a4 100644
--- a/dbms/src/Storages/VirtualColumnUtils.cpp
+++ b/dbms/src/Storages/VirtualColumnUtils.cpp
@@ -97,7 +97,7 @@ static bool isValidFunction(const ASTPtr & expression, const NameSet & columns)
 
     if (const ASTIdentifier * identifier = typeid_cast<const ASTIdentifier *>(&*expression))
     {
-        if (identifier->kind == ASTIdentifier::Kind::Column)
+        if (identifier->general())
             return columns.count(identifier->name);
     }
     return true;
diff --git a/dbms/src/TableFunctions/TableFunctionRemote.cpp b/dbms/src/TableFunctions/TableFunctionRemote.cpp
index 4f7d1c11ac2..acc094408f8 100644
--- a/dbms/src/TableFunctions/TableFunctionRemote.cpp
+++ b/dbms/src/TableFunctions/TableFunctionRemote.cpp
@@ -292,7 +292,7 @@ StoragePtr TableFunctionRemote::executeImpl(const ASTPtr & ast_function, const C
     /// We need to mark them as the name of the database or table, because the default value is column.
     for (auto & arg : args)
         if (ASTIdentifier * id = typeid_cast<ASTIdentifier *>(arg.get()))
-            id->kind = ASTIdentifier::Table;
+            id->setSpecial();
 
     ClusterPtr cluster;
     if (!cluster_name.empty())
diff --git a/dbms/src/TableFunctions/TableFunctionShardByHash.cpp b/dbms/src/TableFunctions/TableFunctionShardByHash.cpp
index 616b6d117d4..4588796edeb 100644
--- a/dbms/src/TableFunctions/TableFunctionShardByHash.cpp
+++ b/dbms/src/TableFunctions/TableFunctionShardByHash.cpp
@@ -66,7 +66,7 @@ StoragePtr TableFunctionShardByHash::executeImpl(const ASTPtr & ast_function, co
     /// Similar to other TableFunctions.
     for (auto & arg : args)
         if (ASTIdentifier * id = typeid_cast<ASTIdentifier *>(arg.get()))
-            id->kind = ASTIdentifier::Table;
+            id->setSpecial();
 
     auto cluster = context.getCluster(cluster_name);
     size_t shard_index = sipHash64(key) % cluster->getShardCount();