diff --git a/src/Interpreters/InterpreterCreateQuery.cpp b/src/Interpreters/InterpreterCreateQuery.cpp
index 586f2d0f056..4c220d43b17 100644
--- a/src/Interpreters/InterpreterCreateQuery.cpp
+++ b/src/Interpreters/InterpreterCreateQuery.cpp
@@ -71,6 +71,7 @@ namespace ErrorCodes
     extern const int BAD_DATABASE_FOR_TEMPORARY_TABLE;
     extern const int SUSPICIOUS_TYPE_FOR_LOW_CARDINALITY;
     extern const int DICTIONARY_ALREADY_EXISTS;
+    extern const  int ILLEGAL_SYNTAX_FOR_DATA_TYPE
 }
 
 
@@ -287,25 +288,25 @@ ColumnsDescription InterpreterCreateQuery::getColumnsDescription(const ASTExpres
         const auto & col_decl = ast->as<ASTColumnDeclaration &>();
 
         DataTypePtr column_type = nullptr;
-        if (!col_decl.isNULL && col_decl.isNot)
-            throw Exception{"Cant use NOT without NULL", ErrorCodes::EMPTY_LIST_OF_COLUMNS_PASSED};
+        if (!col_decl.is_null && col_decl.is_not)
+            throw Exception{"Cant use NOT without NULL", ErrorCodes::ILLEGAL_SYNTAX_FOR_DATA_TYPE};
 
         if (col_decl.type)
         {
             column_type = DataTypeFactory::instance().get(col_decl.type);
 
-            if (col_decl.isNot && col_decl.isNULL) {
+            if (col_decl.is_not && col_decl.is_null) {
                 if (column_type->isNullable())
-                    throw Exception{"Cant use NOT NULL with Nullable", ErrorCodes::EMPTY_LIST_OF_COLUMNS_PASSED};
-            } else if (col_decl.isNULL && !col_decl.isNot) {
+                    throw Exception{"Cant use NOT NULL with Nullable", ErrorCodes::ILLEGAL_SYNTAX_FOR_DATA_TYPE};
+            } else if (col_decl.is_null && !col_decl.is_not) {
                 if (column_type->isNullable())
-                    throw Exception{"Cant use NULL with Nullable", ErrorCodes::EMPTY_LIST_OF_COLUMNS_PASSED};
+                    throw Exception{"Cant use NULL with Nullable", ErrorCodes::ILLEGAL_SYNTAX_FOR_DATA_TYPE};
                 else {
                     column_type = makeNullable(column_type);
                 }
             }
 
-            if (context.getSettingsRef().data_type_default_nullable && !column_type->isNullable() && !col_decl.isNot && !col_decl.isNULL)
+            if (context.getSettingsRef().data_type_default_nullable && !column_type->isNullable() && !col_decl.is_not && !col_decl.is_null)
                 column_type = makeNullable(column_type);
 
             column_names_and_types.emplace_back(col_decl.name, column_type);
diff --git a/src/Parsers/ASTColumnDeclaration.cpp b/src/Parsers/ASTColumnDeclaration.cpp
index 40513b45586..de5abe28ffb 100644
--- a/src/Parsers/ASTColumnDeclaration.cpp
+++ b/src/Parsers/ASTColumnDeclaration.cpp
@@ -16,16 +16,16 @@ ASTPtr ASTColumnDeclaration::clone() const
         res->children.push_back(res->type);
     }
 
-    if (isNULL)
+    if (is_null)
     {
-        res->isNULL = isNULL;
-        res->children.push_back(res->isNULL);
+        res->is_null = is_null;
+        res->children.push_back(res->is_null);
     }
 
-    if (isNot)
+    if (is_not)
     {
-        res->isNot = isNot;
-        res->children.push_back(res->isNot);
+        res->is_not = is_not;
+        res->children.push_back(res->is_not);
     }
 
     if (default_expression)
@@ -71,16 +71,16 @@ void ASTColumnDeclaration::formatImpl(const FormatSettings & settings, FormatSta
         type->formatImpl(settings, state, frame);
     }
 
-    if (isNot)
+    if (is_not)
     {
         settings.ostr << ' ';
-        isNot->formatImpl(settings, state, frame);
+        is_not->formatImpl(settings, state, frame);
     }
 
-    if (isNULL)
+    if (is_null)
     {
         settings.ostr << ' ';
-        isNULL->formatImpl(settings, state, frame);
+        is_null->formatImpl(settings, state, frame);
     }
 
 
diff --git a/src/Parsers/ASTColumnDeclaration.h b/src/Parsers/ASTColumnDeclaration.h
index 406a8cebded..34afd771de2 100644
--- a/src/Parsers/ASTColumnDeclaration.h
+++ b/src/Parsers/ASTColumnDeclaration.h
@@ -13,8 +13,8 @@ class ASTColumnDeclaration : public IAST
 public:
     String name;
     ASTPtr type;
-    ASTPtr isNULL;
-    ASTPtr isNot;
+    ASTPtr is_null;
+    ASTPtr is_not;
     String default_specifier;
     ASTPtr default_expression;
     ASTPtr comment;
diff --git a/src/Parsers/ParserCreateQuery.h b/src/Parsers/ParserCreateQuery.h
index 8976de8f1bc..c2b36460397 100644
--- a/src/Parsers/ParserCreateQuery.h
+++ b/src/Parsers/ParserCreateQuery.h
@@ -10,8 +10,6 @@
 #include <Parsers/CommonParsers.h>
 #include <Poco/String.h>
 
-#include <iostream>
-
 
 namespace DB
 {
@@ -141,8 +139,8 @@ bool IParserColumnDeclaration<NameParser>::parseImpl(Pos & pos, ASTPtr & node, E
       */
     ASTPtr type;
     String default_specifier;
-    ASTPtr isNull;
-    ASTPtr isNot;
+    ASTPtr is_null;
+    ASTPtr is_not;
     ASTPtr default_expression;
     ASTPtr comment_expression;
     ASTPtr codec_expression;
@@ -175,14 +173,14 @@ bool IParserColumnDeclaration<NameParser>::parseImpl(Pos & pos, ASTPtr & node, E
 
     if (s_not.check(pos, expected)) {
         if (s_null.check(pos, expected)) {
-            isNot = std::make_shared<ASTIdentifier>("NOT");
-            isNull = std::make_shared<ASTIdentifier>("NULL");
+            is_not = std::make_shared<ASTIdentifier>("NOT");
+            is_null = std::make_shared<ASTIdentifier>("NULL");
         } else {
             return false;
         }
     } else {
         if (s_null.check(pos, expected)) {
-            isNull = std::make_shared<ASTIdentifier>("NULL");
+            is_null = std::make_shared<ASTIdentifier>("NULL");
         }
     }
 
@@ -215,14 +213,14 @@ bool IParserColumnDeclaration<NameParser>::parseImpl(Pos & pos, ASTPtr & node, E
         column_declaration->children.push_back(std::move(type));
     }
 
-    if (isNull) {
-        column_declaration->isNULL = isNull;
-        column_declaration->children.push_back(std::move(isNull));
+    if (is_null) {
+        column_declaration->is_null = is_null;
+        column_declaration->children.push_back(std::move(is_null));
     }
 
-    if (isNot) {
-        column_declaration->isNot = isNot;
-        column_declaration->children.push_back(std::move(isNot));
+    if (is_not) {
+        column_declaration->is_not = is_not;
+        column_declaration->children.push_back(std::move(is_not));
     }
 
     if (default_expression)