1.查询女读者所有的借阅信息
SELECT t_borrow_record .*    
FROM t_borrow_record  
WHERE reader_id  IN  
     (SELECT reader_id  FROM t_reader
      WHERE reader_sex=‘女’ );

2.询没有借阅记录的读者的信息。
SELECT *    
FROM t_reader a
 WHERE  NOT EXISTS
 (SELECT reader_id  FROM t_borrow_record
WHERE reader_id=a.reader_id);



