The query does not work when looking for null values ​​on the where clause

I got this query that works perfectly:

SELECT FOLDER.folderid, FOLDER.foldername
FROM FOLDER
INNER JOIN COLLABORATORS ON COLLABORATORS.folderid = FOLDER.folderid
WHERE COLLABORATORS.userid = 23

But when I added this on the where clause: "and FOLDER.parent = NULL" it doesnt work. The complete query is:

SELECT FOLDER.folderid, FOLDER.foldername
FROM FOLDER
INNER JOIN COLLABORATORS ON COLLABORATORS.folderid = FOLDER.folderid
WHERE COLLABORATORS.userid = 23 and FOLDER.parent = NULL

Does anyone know whats going on? Thanks

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when dealing with NULL, you cannot use = or <> since the values are unknown but instead use IS NULL or IS NOT NULL,

WHERE COLLABORATORS.userid = 23 and FOLDER.parent IS NULL

• MySQL - Working with NULL Values