CREATE table test1 (id INT, new_id INT, typeof VARCHAR(10));
CREATE table test2 (id INT, new_id INT);
                
CREATE TABLE `test1` (
  `id` int(11) DEFAULT NULL,
  `new_id` int(11) DEFAULT NULL,
  `typeof` varchar(10) DEFAULT NULL
) ENGINE=InnoDB;

CREATE TABLE `test2` (
  `id` int(11) DEFAULT NULL,
  `new_id` int(11) DEFAULT NULL
) ENGINE=InnoDB;

INSERT INTO `test1` (`id`, `new_id`, `typeof`)
VALUES
	(2, 10, 'ECC'),
	(3, 122, 'ECC'),
	(4, 3, 'ECC'),
	(5, 2, 'ECC'),
	(6, 1, 'ECC'),
	(1, 1, NULL);

INSERT INTO `test2` (`id`, `new_id`)
VALUES
	(1, 1),
	(2, 122),
	(4, 3);

        SELECT test1.*,test2.* FROM test1 LEFT JOIN test2 ON test1.new_id=test2.new_id WHERE test1.typeof='ECC'; -- 5
        SELECT test1.*,test2.* FROM test1 LEFT JOIN test2 ON test1.new_id=test2.new_id AND test1.typeof='ECC'; -- 6

LEFT JOIN test2 ON test1.new_id=test2.new_id AND test1.typeof='ECC'

LEFT JOIN test2 ON test1.new_id=test2.new_id AND test1.typeof='ECC'