SQL statements(SQl Server and Oracle)

hi. I would like us to assist each other with any sql statements whether ran from sql server or oracle.

CREATE TABLE users (
id INT GENERATED ALWAYS AS IDENTITY not null primary key,
first_name varchar DEFAULT NULL,
last_name varchar DEFAULT NULL,
username varchar DEFAULT NULL,
password varchar DEFAULT NULL,
PRIMARY KEY (id))
ENGINE = InnoDb DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci ;

CREATE TABLE todos (
id bigint GENERATED ALWAYS AS IDENTITY not null primary key ,
description varchar DEFAULT NULL,
is_done bit(1) NOT NULL,
target_date datetime DEFAULT NULL,
username varchar DEFAULT NULL,
title varchar DEFAULT NULL,
PRIMARY KEY (id))
ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8mb4 COLLATE=utf8_general_ci ;

on typing this this code its shows errors as following i am not able to rectify them

[Warning, Error code 1,064, SQLState 42000] You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ‘IDENTITY not null primary key,
first_name varchar DEFAULT NULL,
last_name va’ at line 2

[Exception, Error code 1,064, SQLState 42000] You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ‘IDENTITY not null primary key,
first_name varchar DEFAULT NULL,
last_name va’ at line 2
Line 1, column 1

[Warning, Error code 1,064, SQLState 42000] You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ‘IDENTITY not null primary key ,
description varchar DEFAULT NULL,
is_done bi’ at line 2

[Exception, Error code 1,064, SQLState 42000] You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ‘IDENTITY not null primary key ,
description varchar DEFAULT NULL,
is_done bi’ at line 2
Line 10, column 1

Execution finished after 0.095 s, 2 errors occurred.

Can you check on that faster please