Google translator skips NULL value in INSERT

I have google spreadsheet table smalla with defined header columns intkey, intnum and other (see attached screenshot).
Following query doesn't insert NULL value to column intnum:
INSERT INTO smalla(intnum, intkey) values (null, 562)
Instead, it inserts 562 to intnum and NULL to intkey.
(Server log shows no exception)

INSERT works correctly if none of the inserted values is NULL.