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我正在尝试在Oracle 11g上运行此代码,它在下面给出了错误.我似乎无法做对.

DECLARE
    CURSOR bookcursor IS
    SELECT btName, BookCopy.Isbn, pubName, dateDestroyed
      FROM booktitle bt
      JOIN publisher p
        ON bt.pubId = p.pubId 
      JOIN bookcopy bc
        ON bt.Isbn = bc.Isbn 
     WHERE datedestroyed IS NULL
    ;
    bookcursorrec bookcursor%ROWTYPE;
BEGIN
    OPEN bookcursor;
    LOOP
        FETCH bookcursor INTO bookcursorrer;
        EXIT WHEN bookcursor%NOTFOUND;
        dbms_output.put_line( 'ISBN: ' ||bookcursorrec.isbn
                              || ' - Book Name: ' || bookcursorrec.btname
                              || ' - Publisher: ' || bookcursorrec.pubname );
    END LOOP;
    CLOSE bookcursor;
END;


ERROR at line 3:
ORA-06550: line 3, column 20: …