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
selectdatepart(dd,dateadd(dd,-1,dateadd(mm,1,cast(cast(year(getdate()) asvarchar)+'-'+cast(month(getdate()) as varchar)+'-01' as datetime))))
Question2：Can you use a SQL statement to calculating it!
Howcan 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 otherprices?
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!
Howcan I get the report about sale quality for each store and each quarterand the total sale quality for each quarter at year 1993?
You can use the table sales and stores in datatabase pubs.
TableSales record all sale detail item for each store. Column store_id isthe id of each store, ord_date is the order date of each sale item, andcolumn qty is the sale qulity. Table stores record all storeinformation.
I want to get the result look like as below:
Output:
stor_name Total Qtr1 Qtr2 Qtr3 Qtr4
---------------------------------------- ----------- ----------- ----------- ----------- -----------
Barnum's 50 0 50 0 0
Bookbeat 55 25 30 0 0
Doc-U-Mat: Quality Laundry and Books 85 0 85 0 0
Fricative Bookshop 60 35 0 0 25
Total 250 60 165 0 25
Answer 4：用动态SQL实现
Question5: The Fastest Way to Recompile All Stored Procedures
Ihave a problem with a database running in SQL Server 6.5 (Service Pack4). We moved the database (object transfer) from one machine to anotherlast night, and an error (specific to a stored procedure) is croppingup. However, I can't tell which procedure is causing it. Permissionsare granted in all of our stored procedures; is there a way from theisql utility to force all stored procedures to recompile?
Tips: sp_recompile can recomplie a store procedure each time
Answer 5：在执行存储过程时,使用 with recompile 选项强制编译新的计划；使用sp_recompile系统存储过程强制在下次运行时进行重新编译
Question6: How can I add row numbers to my result set?
In database pubs, have a table titles , now I want the result shown as below,each row have a row number, how can you do that?
Result:
line-no title_id
----------- --------
1 BU1032
2 BU1111
3 BU2075
4 BU7832
5 MC2222
6 MC3021
7 MC3026
8 PC1035
9 PC8888
10 PC9999
11 PS1372
12 PS2091
13 PS2106
14 PS3333
15 PS7777
16 TC3218
17 TC4203
18 TC7777
--SQL 2005的写法
select row_number() as line_no ,title_id from titles
--SQL 2000的写法
select line_no identity(int,1,1),title_id into #t from titles
select * from #t
drop table #t
Question 7: Can you tell me what the difference of two SQL statements at performance of execution?
Statement 1:
if NOT EXISTS ( select * from publishers where state = 'NY')
begin
SELECT 'Sales force needs to penetrate New York market'
end
else
begin
SELECT 'We have publishers in New York'
end
Statement 2:
if EXISTS ( select * from publishers where state = 'NY')
begin
SELECT 'We have publishers in New York'
end
else
begin
SELECT 'Sales force needs to penetrate New York market'
end
Answer 7：不同点:执行时的事务数,处理时间,从客户端到服务器端传送的数据量大小
Question8: How can I list all California authors regardless of whether they have written a book?
Indatabase pubs, have a table authors and titleauthor , table authors hasa column state, and titleauhtor have books each author written.
CA behalf of california in table authors.
Answer 8：
select * from authors where state='CA'
Question9: How can I get a list of the stores that have bought both 'bussiness' and 'mod_cook' type books?
In database pubs, use three table stores,sales and titles to implement this requestment.
Now I want to get the result as below:
stor_id stor_name
------- ----------------------------------------
...
7896 Fricative Bookshop
...
...
...
Answer 9：
select distinct a.stor_id, a.stor_name from stores a,sales b,titles c
where a.stor_id=b.stor_id and b.title_id=c.title_id and c.type='business' and
exists(select 1 from sales k,titles g where stor_id=b.stor_id
and k.title_id=g.title_id and g.type='mod_cook')
Question10: How can I list non-contignous data?
In database pubs, I create a table test using statement as below, and I insert several row as below
create table test
( id int primary key )
go
insert into test values (1 )
insert into test values (2 )
insert into test values (3 )
insert into test values (4 )
insert into test values (5 )
insert into test values (6 )
insert into test values (8 )
insert into test values (9 )
insert into test values (11)
insert into test values (12)
insert into test values (13)
insert into test values (14)
insert into test values (18)
insert into test values (19)
go
Now I want to list the result of the non-contignous row as below,how can I do it?
Missing after Missing before
------------- --------------
6 8
9 11
...
Answer 10：
select id from test t where not exists(select 1 from test where id=t.id+1)
or not exists(select 1 from test where id=t.id-1)
Question11: How can I list all book with prices greather than the average price of books of the same type?
Indatabase pubs, have a table named titles , its column named price meanthe price of the book, and another named type mean the type of books.
Now I want to get the result as below:
type title price
------------ -------------------------------------------------------------------------------- ---------------------
business The Busy Executive's Database Guide 19.9900
...
...
...
...
select a.type,a.title,a.price from titles a,
(select type,price=avg(price) from titles group by type)b
where a.type=b.type and a.price>b.price
试题点评：通览整个试题，我们不难发现，这份试题是针对SQLServer数据库人员的。而从难度分析上来看，这份试题也属于同类试题中比较难的了。之所以说它难，首先是限定时间的全英文试题；其次，尽管这份试题主要是考核开发能力，但却涉及到了算法的选择和性能的调优；最后，这份试题还夹进了SQLServer数据库的升级问题。因此，综上所述，我们估计这是一家从事程序外包工作的外企招聘后台开发或与后台开发相关的SQLServer高级程序员的试题。