diff --git a/src/sql/parser/ob_fast_parser.cpp b/src/sql/parser/ob_fast_parser.cpp
index 118c5d3bf7..12a7b24a02 100644
--- a/src/sql/parser/ob_fast_parser.cpp
+++ b/src/sql/parser/ob_fast_parser.cpp
@@ -2025,7 +2025,12 @@ int ObFastParserMysql::process_string(const char quote)
           ret = OB_ALLOCATE_MEMORY_FAILED;
           LOG_WARN("fail to alloc memory", K(ret), K(need_mem_size));
         } else {
-          ParseNode *node = new_node(buf, T_VARCHAR);
+          ObItemType param_type = T_VARCHAR;
+          if ('n' == raw_sql_.char_at(cur_token_begin_pos_) ||
+              'N' == raw_sql_.char_at(cur_token_begin_pos_)) {
+            param_type = T_NCHAR;
+          }
+          ParseNode *node = new_node(buf, param_type);
           if (NULL != child_node) {
             node->num_child_ = 1;
             node->children_ = child_node;
@@ -2056,6 +2061,8 @@ int ObFastParserMysql::process_identifier_begin_with_n()
       cur_token_type_ = PARAM_TOKEN;
       OZ (add_null_type_node());
     }
+  } else if ('\'' == raw_sql_.char_at(raw_sql_.cur_pos_)) {
+    OZ (process_string('\''));
   } else {
   }
   return ret;
diff --git a/src/sql/parser/sql_parser_mysql_mode.l b/src/sql/parser/sql_parser_mysql_mode.l
index 5825220a1d..7693d56d4b 100755
--- a/src/sql/parser/sql_parser_mysql_mode.l
+++ b/src/sql/parser/sql_parser_mysql_mode.l
@@ -285,6 +285,26 @@ FALSE {
   return BOOL_VALUE;
 }
 
+("N"|"n"){sqbegin} {
+  BEGIN(sq);
+  ParseResult *p = (ParseResult *)yyextra;
+  p->start_col_ = yylloc->first_column;
+  char **tmp_literal = &(p->tmp_literal_);
+  if (NULL == *tmp_literal)
+  {
+    *tmp_literal = (char*) parse_malloc(p->input_sql_len_ + 1, p->malloc_pool_);
+    check_malloc(*tmp_literal);
+  }
+  check_value(yylval);
+  malloc_new_node(yylval->node, p->malloc_pool_, T_NCHAR, 0);
+
+  yylval->node->str_len_ = 0;
+  if (IS_FAST_PARAMETERIZE && !IS_NEED_PARAMETERIZE) {
+    COPY_WRITE();
+  }
+}
+
+
 {sqbegin} {
   BEGIN(sq);
   ParseResult *p = (ParseResult *)yyextra;
@@ -305,6 +325,7 @@ FALSE {
   check_value(yylval);
   yylloc->first_column = p->start_col_;
   FORMAT_STR_NODE(yylval->node);
+  int32_t token_ret = yylval->node->type_ == T_NCHAR ? NATIONAL_LITERAL : STRING_VALUE;
   yylval->node->text_len_ = yylloc->last_column - p->start_col_ + 1;
   COPY_STRING(p->input_sql_ + p->start_col_ - 1, yylval->node->text_len_, yylval->node->raw_text_);
   if (IS_FAST_PARAMETERIZE) {
@@ -312,7 +333,7 @@ FALSE {
   } else {
     yylval->node->sql_str_off_ = yylloc->first_column;
     setup_token_pos_info(yylval->node, yylloc->first_column, yylval->node->text_len_ - 2);
-    return STRING_VALUE;
+    return token_ret;
   }
 }
 
diff --git a/src/sql/parser/sql_parser_mysql_mode.y b/src/sql/parser/sql_parser_mysql_mode.y
index 56f9a4f6e4..c6b2017a15 100755
--- a/src/sql/parser/sql_parser_mysql_mode.y
+++ b/src/sql/parser/sql_parser_mysql_mode.y
@@ -54,6 +54,7 @@ extern void obsql_oracle_parse_fatal_error(int32_t errcode, yyscan_t yyscanner,
 
 %token <node> NAME_OB
 %token <node> STRING_VALUE
+%token <node> NATIONAL_LITERAL
 %token <node> INTNUM
 %token <node> DATE_VALUE
 %token <node> TIMESTAMP_VALUE
@@ -939,6 +940,10 @@ STRING_VALUE %prec LOWER_THAN_COMP
   make_name_node(concat_node, result->malloc_pool_, "concat");
   malloc_non_terminal_node($$, result->malloc_pool_, T_FUN_SYS, 2, concat_node, string_list_node);
 }
+| NATIONAL_LITERAL
+{
+   $$ = $1;
+}
 ;
 
 charset_introducer:
@@ -5222,6 +5227,52 @@ int_type_i opt_int_length_i opt_unsigned_i opt_zerofill_i
   $$->int32_values_[1] = 0; /* is char */
   $$->sql_str_off_ = @1.first_column;
 }
+| NCHAR opt_string_length_i opt_binary
+{
+  ParseNode *charset_node = NULL;
+  ParseNode *charset_name = NULL;
+  malloc_terminal_node(charset_name, result->malloc_pool_, T_VARCHAR);
+  malloc_terminal_node(charset_node, result->malloc_pool_, T_CHARSET);
+  charset_name->str_value_ = parse_strdup("utf8mb4", result->malloc_pool_, &(charset_name->str_len_));
+  if (OB_UNLIKELY(NULL == charset_name->str_value_)) {
+    yyerror(NULL, result, "No more space for mallocing string\n");
+    YYABORT_NO_MEMORY;
+  }
+  charset_name->type_ = T_CHAR_CHARSET;
+  charset_name->param_num_ = 0;
+  charset_name->is_hidden_const_ = 1;
+  charset_node->str_value_ = charset_name->str_value_;
+  charset_node->str_len_ = charset_name->str_len_;
+  charset_node->sql_str_off_ = charset_name->sql_str_off_;
+
+  malloc_non_terminal_node($$, result->malloc_pool_, T_CHAR, 3, charset_node, NULL, $3);
+  $$->int32_values_[0] = $2[0];
+  $$->int32_values_[1] = 0; /* is char */
+  $$->sql_str_off_ = @1.first_column;
+}
+| NATIONAL CHARACTER opt_string_length_i opt_binary
+{
+  ParseNode *charset_node = NULL;
+  ParseNode *charset_name = NULL;
+  malloc_terminal_node(charset_name, result->malloc_pool_, T_VARCHAR);
+  malloc_terminal_node(charset_node, result->malloc_pool_, T_CHARSET);
+  charset_name->str_value_ = parse_strdup("utf8mb4", result->malloc_pool_, &(charset_name->str_len_));
+  if (OB_UNLIKELY(NULL == charset_name->str_value_)) {
+    yyerror(NULL, result, "No more space for mallocing string\n");
+    YYABORT_NO_MEMORY;
+  }
+  charset_name->type_ = T_CHAR_CHARSET;
+  charset_name->param_num_ = 0;
+  charset_name->is_hidden_const_ = 1;
+  charset_node->str_value_ = charset_name->str_value_;
+  charset_node->str_len_ = charset_name->str_len_;
+  charset_node->sql_str_off_ = charset_name->sql_str_off_;
+  malloc_non_terminal_node($$, result->malloc_pool_, T_CHAR, 3, charset_node, NULL, $4);
+  $$->int32_values_[0] = $3[0];
+  $$->int32_values_[1] = 0; /* is char */
+  $$->sql_str_off_ = @1.first_column;
+}
+
 /*  | TEXT opt_binary opt_charset opt_collation
 //  {
 //    (void)($2);
@@ -5235,12 +5286,98 @@ int_type_i opt_int_length_i opt_unsigned_i opt_zerofill_i
   $$->int32_values_[0] = $2[0];
   $$->int32_values_[1] = 0; /* is char */
 }
+| NCHAR VARCHAR string_length_i opt_binary
+{
+  ParseNode *charset_node = NULL;
+  ParseNode *charset_name = NULL;
+  malloc_terminal_node(charset_name, result->malloc_pool_, T_VARCHAR);
+  malloc_terminal_node(charset_node, result->malloc_pool_, T_CHARSET);
+  charset_name->str_value_ = parse_strdup("utf8mb4", result->malloc_pool_, &(charset_name->str_len_));
+  if (OB_UNLIKELY(NULL == charset_name->str_value_)) {
+    yyerror(NULL, result, "No more space for mallocing string\n");
+    YYABORT_NO_MEMORY;
+  }
+  charset_name->type_ = T_CHAR_CHARSET;
+  charset_name->param_num_ = 0;
+  charset_name->is_hidden_const_ = 1;
+  charset_node->str_value_ = charset_name->str_value_;
+  charset_node->str_len_ = charset_name->str_len_;
+  charset_node->sql_str_off_ = charset_name->sql_str_off_;
+
+  malloc_non_terminal_node($$, result->malloc_pool_, T_VARCHAR, 3, charset_node, NULL, $4);
+  $$->int32_values_[0] = $3[0];
+  $$->int32_values_[1] = 0; /* is char */
+}
+| NVARCHAR string_length_i opt_binary
+{
+  ParseNode *charset_node = NULL;
+  ParseNode *charset_name = NULL;
+  malloc_terminal_node(charset_name, result->malloc_pool_, T_VARCHAR);
+  malloc_terminal_node(charset_node, result->malloc_pool_, T_CHARSET);
+  charset_name->str_value_ = parse_strdup("utf8mb4", result->malloc_pool_, &(charset_name->str_len_));
+  if (OB_UNLIKELY(NULL == charset_name->str_value_)) {
+    yyerror(NULL, result, "No more space for mallocing string\n");
+    YYABORT_NO_MEMORY;
+  }
+  charset_name->type_ = T_CHAR_CHARSET;
+  charset_name->param_num_ = 0;
+  charset_name->is_hidden_const_ = 1;
+  charset_node->str_value_ = charset_name->str_value_;
+  charset_node->str_len_ = charset_name->str_len_;
+  charset_node->sql_str_off_ = charset_name->sql_str_off_;
+
+  malloc_non_terminal_node($$, result->malloc_pool_, T_VARCHAR, 3, charset_node, NULL, $3);
+  $$->int32_values_[0] = $2[0];
+  $$->int32_values_[1] = 0; /* is char */
+}
+| NATIONAL VARCHAR string_length_i opt_binary
+{
+  ParseNode *charset_node = NULL;
+  ParseNode *charset_name = NULL;
+  malloc_terminal_node(charset_name, result->malloc_pool_, T_VARCHAR);
+  malloc_terminal_node(charset_node, result->malloc_pool_, T_CHARSET);
+  charset_name->str_value_ = parse_strdup("utf8mb4", result->malloc_pool_, &(charset_name->str_len_));
+  if (OB_UNLIKELY(NULL == charset_name->str_value_)) {
+    yyerror(NULL, result, "No more space for mallocing string\n");
+    YYABORT_NO_MEMORY;
+  }
+  charset_name->type_ = T_CHAR_CHARSET;
+  charset_name->param_num_ = 0;
+  charset_name->is_hidden_const_ = 1;
+  charset_node->str_value_ = charset_name->str_value_;
+  charset_node->str_len_ = charset_name->str_len_;
+  charset_node->sql_str_off_ = charset_name->sql_str_off_;
+  malloc_non_terminal_node($$, result->malloc_pool_, T_VARCHAR, 3, charset_node, NULL, $4);
+  $$->int32_values_[0] = $3[0];
+  $$->int32_values_[1] = 0; /* is char */
+}
 | CHARACTER VARYING string_length_i opt_binary opt_charset opt_collation
 {
   malloc_non_terminal_node($$, result->malloc_pool_, T_VARCHAR, 3, $5, $6, $4);
   $$->int32_values_[0] = $3[0];
   $$->int32_values_[1] = 0; /* is char */
 }
+| NATIONAL CHARACTER VARYING string_length_i opt_binary
+{
+  ParseNode *charset_node = NULL;
+  ParseNode *charset_name = NULL;
+  malloc_terminal_node(charset_name, result->malloc_pool_, T_VARCHAR);
+  malloc_terminal_node(charset_node, result->malloc_pool_, T_CHARSET);
+  charset_name->str_value_ = parse_strdup("utf8mb4", result->malloc_pool_, &(charset_name->str_len_));
+  if (OB_UNLIKELY(NULL == charset_name->str_value_)) {
+    yyerror(NULL, result, "No more space for mallocing string\n");
+    YYABORT_NO_MEMORY;
+  }
+  charset_name->type_ = T_CHAR_CHARSET;
+  charset_name->param_num_ = 0;
+  charset_name->is_hidden_const_ = 1;
+  charset_node->str_value_ = charset_name->str_value_;
+  charset_node->str_len_ = charset_name->str_len_;
+  charset_node->sql_str_off_ = charset_name->sql_str_off_;
+  malloc_non_terminal_node($$, result->malloc_pool_, T_VARCHAR, 3, charset_node, NULL, $5);
+  $$->int32_values_[0] = $4[0];
+  $$->int32_values_[1] = 0; /* is char */
+}
 | blob_type_i opt_string_length_i_v2
 {
   malloc_terminal_node($$, result->malloc_pool_, $1[0]);
diff --git a/src/sql/resolver/ob_resolver_utils.cpp b/src/sql/resolver/ob_resolver_utils.cpp
index 25e48266b9..c2a619b7c2 100644
--- a/src/sql/resolver/ob_resolver_utils.cpp
+++ b/src/sql/resolver/ob_resolver_utils.cpp
@@ -1982,6 +1982,34 @@ int ObResolverUtils::resolve_stmt_type(const ParseResult &result, stmt::StmtType
   return ret;
 }
 
+int ObResolverUtils::set_string_val_charset(ObObjParam &val, ObString &charset, ObObj &result_val,
+                                            bool is_strict_mode,
+                                            bool return_ret)
+{
+  int ret = OB_SUCCESS;
+  ObCharsetType charset_type = CHARSET_INVALID;
+  if (CHARSET_INVALID == (charset_type = ObCharset::charset_type(charset.trim()))) {
+    ret = OB_ERR_UNKNOWN_CHARSET;
+    LOG_USER_ERROR(OB_ERR_UNKNOWN_CHARSET, charset.length(), charset.ptr());
+  } else {
+    // use the default collation of the specified charset
+    ObCollationType collation_type = ObCharset::get_default_collation(charset_type);
+    val.set_collation_type(collation_type);
+    LOG_DEBUG("use default collation", K(charset_type), K(collation_type));
+    ObLength length = static_cast<ObLength>(ObCharset::strlen_char(val.get_collation_type(),
+          val.get_string_ptr(),
+          val.get_string_len()));
+    val.set_length(length);
+
+    // 为了跟mysql报错一样，这里检查一下字符串是否合法，仅仅是检查，不合法则报错，不做其他操作
+    // check_well_formed_str的ret_error参数为true的时候，is_strict_mode参数失效，因此这里is_strict_mode直接传入true
+    if (OB_SUCC(ret) && OB_FAIL(ObSQLUtils::check_well_formed_str(val, result_val, is_strict_mode, return_ret))) {
+      LOG_WARN("invalid str", K(ret), K(val), K(is_strict_mode), K(return_ret));
+    }
+  }
+  return ret;
+}
+
 int ObResolverUtils::resolve_const(const ParseNode *node,
                                    const stmt::StmtType stmt_type,
                                    ObIAllocator &allocator,
@@ -2040,7 +2068,8 @@ int ObResolverUtils::resolve_const(const ParseNode *node,
         ObString str_val;
         ObObj result_val;
         str_val.assign_ptr(const_cast<char *>(node->str_value_), static_cast<int32_t>(node->str_len_));
-        val.set_string(static_cast<ObObjType>(node->type_), str_val);
+        val.set_string(lib::is_mysql_mode() && is_nchar ?
+                              ObVarcharType : static_cast<ObObjType>(node->type_), str_val);
         // decide collation
         /*
          MySQL determines a literal's character set and collation in the following manner:
@@ -2061,7 +2090,14 @@ int ObResolverUtils::resolve_const(const ParseNode *node,
 //        } else if (0 == node->num_child_) {
         if (0 == node->num_child_) {
           // for STRING without collation, e.g. show tables like STRING;
-          val.set_collation_type(connection_collation);
+          if (lib::is_mysql_mode() && is_nchar) {
+            ObString charset(strlen("utf8mb4"), "utf8mb4");
+            if (OB_FAIL(set_string_val_charset(val, charset, result_val, false, false))) {
+              LOG_WARN("set string val charset failed", K(ret));
+            }
+          } else {
+            val.set_collation_type(connection_collation);
+          }
         } else {
           // STRING in SQL expression
           ParseNode *charset_node = NULL;
@@ -2076,31 +2112,15 @@ int ObResolverUtils::resolve_const(const ParseNode *node,
             ObCollationType collation_type = CS_TYPE_INVALID;
             if (charset_node != NULL) {
               ObString charset(charset_node->str_len_, charset_node->str_value_);
-              if (CHARSET_INVALID == (charset_type = ObCharset::charset_type(charset.trim()))) {
-                ret = OB_ERR_UNKNOWN_CHARSET;
-                LOG_USER_ERROR(OB_ERR_UNKNOWN_CHARSET, charset.length(), charset.ptr());
-              } else {
-                // use the default collation of the specified charset
-                collation_type = ObCharset::get_default_collation(charset_type);
-                val.set_collation_type(collation_type);
-                LOG_DEBUG("use default collation", K(charset_type), K(collation_type));
-                ObLength length = static_cast<ObLength>(ObCharset::strlen_char(val.get_collation_type(),
-                      val.get_string_ptr(),
-                      val.get_string_len()));
-                val.set_length(length);
-
-                // 为了跟mysql报错一样，这里检查一下字符串是否合法，仅仅是检查，不合法则报错，不做其他操作
-                // check_well_formed_str的ret_error参数为true的时候，is_strict_mode参数失效，因此这里is_strict_mode直接传入true
-                if (OB_SUCC(ret) && OB_FAIL(ObSQLUtils::check_well_formed_str(val, result_val, true, true))) {
-                  LOG_WARN("invalid str", K(ret), K(val));
-                }
+              if (OB_FAIL(set_string_val_charset(val, charset, result_val, false, false))) {
+                LOG_WARN("set string val charset failed", K(ret));
               }
             }
           }
         }
         ObLengthSemantics length_semantics = LS_DEFAULT;
         if (OB_SUCC(ret)) {
-          if (T_NVARCHAR2 == node->type_ || T_NCHAR == node->type_) {
+          if (lib::is_oracle_mode() && (T_NVARCHAR2 == node->type_ || T_NCHAR == node->type_)) {
             length_semantics = LS_CHAR;
           } else {
             length_semantics = default_length_semantics;
diff --git a/src/sql/resolver/ob_resolver_utils.h b/src/sql/resolver/ob_resolver_utils.h
index 766f2986b9..10d924d6a3 100644
--- a/src/sql/resolver/ob_resolver_utils.h
+++ b/src/sql/resolver/ob_resolver_utils.h
@@ -344,6 +344,12 @@ public:
                            const ObSQLMode mode,
                            bool is_from_pl = false);
 
+  static int set_string_val_charset(ObObjParam &val,
+                                    ObString &charset,
+                                    ObObj &result_val,
+                                    bool is_strict_mode,
+                                    bool return_ret);
+
   static int resolve_data_type(const ParseNode &type_node,
                                const common::ObString &ident_name,
                                common::ObDataType &data_type,