//这个是求pddate与系统时间的天数差
select 
        bookId,bookName,booktypeId,pbName,author,
        context,smallImg,bigImg,price,pbdate,
        bookStates,    ygcprice ,num
from bookInfo
 where num<10 and Datediff(Day, pbdate, Getdate()) >= 15 order by 

pbdate ,num asc




select  top 5
        bookId,bookName,booktypeId,pbName,author,
        context,smallImg,bigImg,price,pbdate,
        bookStates,    ygcprice ,num
from bookInfo  where bookStates <> 4 and  booktypeId <> 0
and    
    bookId not in
    (select top 0
     bookId from bookInfo  where bookStates <> 4 and  booktypeId <> 0
    )




select  top 2
        bookId,bookName,booktypeId,pbName,author,
        context,smallImg,bigImg,price,pbdate,
        bookStates,    ygcprice ,num
from bookInfo  where bookStates  = 2 and  booktypeId  = 21
and    
    bookId not in
    (select top 0
     bookId from bookInfo  where bookStates  = 2 and  booktypeId  = 21
    )