Mysql: Copy data from one tabe to another

Create and populate tables:

CREATE TABLE table_a (
  id INT(11) DEFAULT NULL,
  column_a INT(11) DEFAULT NULL
);
CREATE TABLE table_b (
  id INT(11) DEFAULT NULL,
  column_b INT(11) DEFAULT NULL
);
INSERT INTO table_a VALUES 
  (1, 10),
  (2, 20),
  (3, 30),
  (4, NULL),
  (5, 0);

Copy data into second table:

INSERT INTO table_b SELECT id, column_a FROM table_a;

Check results:

SELECT * FROM table_b;
+------+----------+
| id   | column_a |
+------+----------+
|    1 |       10 |
|    2 |       20 |
|    3 |       30 |
|    4 |     NULL |
|    5 |        0 |