)

12）查询正在借阅的图书信息。

select * from book

where bnum in ( select bnum

from br

where brdate not like 'null' and brback like null )

13）查询借阅了机械工业出版社出版的书名中含有数'据库书'三个字的图书、或者借阅了科学出版社出版的书名中含有数'据库书'三个字的图书的读者姓名、书名。

select rname,bname from book,rea,br

where bname like '%数据库%' and rea.rnum in ( select br.rnum

from br,book

where bpub = '机械工业出版社' or bpub = '科学出版社' )

14）查询借阅了机械工业出版社出版的书名中含有数'据库书'三个字的图书并且也借阅了科学出版社出版的书名中含有数'据库书'三个字的图书的读者姓名、书名。

select rname,bname from book,rea,br

where bname = '%数据库%' and rea.rnum in ( select br.rnum

from br r1,br r2,book

where r1.rnum = r2.rnum and book.bnum =br.bnum and bpub = '机械工业出版社' and bpub = '科学出版社' )

15）查询借阅了机械工业出版社出版的书名中含有数'据库书'三个字的图书

但没有借阅了科学出版社出版的书名中含有数'据库书'三个字的图书的读者姓名、书名。

select rname,bname from book,rea,br

where bname like '%数据库%' and rea.rnum in ( select br.rnum

from br ,book

where br.bnum = book.bnum

and bpub = '机械工业出版社' and book.bnum in (select br.rnum

from br,book

where book.bnum = br.bnum and bname like '%数据库%' and bpub = '科学出版社')

)