[Sql server]某外企SQL Server面试题

Question 1：Can you use a batch SQL or store procedure to calculating the Number of Days in a Month

　　Answer 1：找出当月的天数
select datepart(dd,dateadd(dd,-1,dateadd(mm,1,cast(cast(year(getdate()) as varchar)+'-'+cast(month(getdate()) as varchar)+'-01' as datetime))))

　　Question2：Can you use a SQL statement to calculating it!
How can I print "10 to 20" for books that sell for between $10 and $20，"unknown" for books whose price is null, and "other" for all other prices?

　　Answer 2：
　　select bookid,bookname,price=case when price is null then 　　'unknown'
when  price between 10 and 20 then '10 to 20' else price end
from books

　　Question3：Can you use a SQL statement to finding duplicate 　　values!
　　How can I find authors with the same last name?
You can use the table authors in datatabase pubs. I want to get the result as below:
Output:
au_lname   number_dups
---------------------------------------- -----------
Ringer  2
(1 row(s) affected)

　　Answer 3
　　select au_lname,number_dups=count(1) from authors group by au_lname

　　Question4：Can you create a cross-tab report in my SQL Server!
　　How can I get the report about sale quality for each store and each quarter and the total sale quality for each quarter at year 1993?

　　You can use the table sales and stores in datatabase pubs.
Table Sales record all sale detail item for each store. Column store_id is the id of each store, ord_date is the order date of each sale item, and column qty is the sale qulity. Table stores record all store information.
I want to get the result look like as below:
Output: