Problem with renaming a field in sql table

So i have this table:

mysql> SELECT * FROM artists LIMIT 5; 

    +----+----------------+------------+----------+----------------+--------+--------+
    | id | name           | start_year | end_year | origin         | type   | gender |
    +----+----------------+------------+----------+----------------+--------+--------+
    |  4 | Massive Attack |       1987 |     NULL | United Kingdom | Group  | NULL   |
    | 17 | Bob Dylan      |       1941 |     NULL | United States  | Person | Male   |
    | 20 | Art of Noise   |       1983 |     2000 | United Kingdom | Group  | NULL   |
    | 25 | Pavement       |       1989 |     2000 | United States  | Group  | NULL   |
    | 29 | Stevie Wonder  |       1950 |     NULL | United States  | Person | Male   |
    +----+----------------+------------+----------+----------------+--------+--------+


mysql> SELECT name, end_year FROM artists WHERE name IN ("Black Box Recorder");

    +--------------------+----------+
    | name               | end_year |
    +--------------------+----------+
    | Black Box Recorder |     2010 |
    +--------------------+----------+

I then make the table smaller to show what i want to rename which is the end year, and i want to change it to NULL. I have tried this command:

UPDATE artists SET end_year='NULL' WHERE name='Black Box Recorder';

and i thought this command should be correct but it gives this error:

ERROR 1366 (HY000): Incorrect integer value ‘NULL’ for column
‘end_year’ at row 155

>Solution :

Please remove quotes from ‘NULL’ in your update statement.

UPDATE artists SET end_year=NULL WHERE name='Black Box Recorder';