SQL常見面試題

1、SQL 常見面試題1.用一條SQL語句 查詢出每門課都大于80分的學生姓名  name   kecheng   fenshu 張三     語文       81張三     數(shù)學       75李四     語文       76李四 

2、    數(shù)學       90王五     語文       81王五     數(shù)學       100王五     英語       90A: select distinct name from table&

3、#160; where  name not in (select distinct name from table where fenshu<=80)2.學生表 如下:自動編號   學號   姓名 課程編號 課程名稱 分數(shù)1        2005001  張三  0001      數(shù)學    692      

4、;  2005002  李四  0001      數(shù)學    893        2005001  張三  0001      數(shù)學    69刪除除了自動編號不同,其他都相同的學生冗余信息A: delete tablename where 自動編號 not in(select min(自動編號) from tab

5、lename group by 學號,姓名,課程編號,課程名稱,分數(shù))3. 表A(單位名稱，單位帳號), 表B(單位編號，個人賬號)列出各單位的名稱，賬號，以及單位的人數(shù)select A.name, A.dwzh, isnull(Ct.Quantity,'0') as Quantity from Aleft join (select dwzh, count(*) as Quantity from Bgroup by dwzh) as Cton A.dwzh = Ct.dwzh4. 股票表(股票代碼，買賣類型，數(shù)量)按照股票代碼列出，買的數(shù)量，賣的數(shù)量。select isnull

6、(a.StockID, b.StockID), isnull(a.S,'0'), isnull(b.B,'0') from (select StockID,sum(quantity) as S from stockswhere sType = 's'group by StockID ) afull join (select StockID,sum(quantity) as B from stockswhere sType = 'b'group by StockID ) bon a.StockID = b.StockID5. sel

7、ect * from tempT where ','+ tempT.description + ',' like '%,1,%'SQL Server 數(shù)據(jù)庫的高級操作(1) 批處理(2) 變量(3) 邏輯控制(4) 函數(shù)(5) 高級查詢*/(1)批處理將多條SQL語句作為一個整體去編譯，生成一個執(zhí)行計劃，然后，執(zhí)行！理解批處理的關(guān)鍵在于"編譯"，對于由多條語句組成的一個批處理，如果在編譯時，其中，有一條出現(xiàn)語法錯誤，將會導(dǎo)致編譯失??！create table t(a int,b int)- 注釋- 如果多行注釋中包含了批處理的

8、標識符go- 在編譯的過程中代碼將會被go分割成多個部分來分批編譯- 多行注釋的標記將會被分隔而導(dǎo)致編譯出錯- 以下幾條語句是三個非常經(jīng)典的批處理- 你猜一下會添加幾條記錄！/*insert into t values (1,1)go*/insert into t values (2,2)go/*insert into t values (3,3)*/go- 查詢看添加了幾條記錄select * from ttruncate table t(2)變量- 全局變量SQL Server中全局變量由系統(tǒng)定義、系統(tǒng)維護，用戶一般僅可對其進行讀??！- 查看SQL Server版本print versio

9、n- 服務(wù)器名稱print servername- 系統(tǒng)錯誤編號insert into t values ('a','a')print errorinsert into t values ('a','a')if error = 245 print 'Error'- SQL Server 版本的語言信息print LANGUAGE- 一周的第一天從星期幾算起print datefirst- CPU 執(zhí)行命令所耗費時間的累加print cpu_busy- 獲取最近添加的標識列的值create table tt

10、(a int identity(3, 10),b int)insert into tt (b) values (1)print identityselect * from tt- 局部變量局部變量由用戶定義，僅可在同一個批處理中調(diào)用和訪問declare intAge tinyintset intAge = 12print intAgedeclare strName varchar(12)select strName = 'state'print strNameselect au_lname, strName from authors(3)邏輯控制- IF條件判斷declare

11、i intset i = 12if (i > 10) begin    -   print 'Dadadada!'  print 'Dadadada!' end    - else begin  print 'XiaoXiao!'  print 'XiaoXiao!' end- While循環(huán)控制declare i int;se

12、t i = 12;print ireturn;while (i < 18)begin print i; set i = i + 1; if i < 17  continue; if i > 15  break;end;- CASE 分支判斷select au_lname, state, '猶他州' from authors where state = 'UT'select au_lname, state, '密西西比州' from authors w

13、here state = 'MI'select au_lname, state, '肯塔基州' from authors where state = 'KS'select au_lname, state,  case state when 'UT' then '猶他州' when 'MI' then '密西西比州' when 'KS' then '肯塔基州' when 'CA' then

14、 '加利福利亞' else state endfrom authors(4.1)系統(tǒng)函數(shù)- 獲取指定字符串中左起第一個字符的ASC碼print ascii('ABCDEF')- 根據(jù)給定的ASC碼獲取相應(yīng)的字符print char(65)- 獲取給定字符串的長度print len('abcdef')- 大小寫轉(zhuǎn)換print lower('ABCDEF')print upper('abcdef')- 去空格print ltrim('    abcd 

15、 dfd  df  ')print rtrim('    abcd  dfd  df  ')- 求絕對值print abs(-12)- 冪- 3 的 2 次方print power(3,2)print power(3,3)- 隨機數(shù)- 0 - 1000 之間的隨機數(shù)print rand() * 1000 - 獲取圓周率print pi()- 獲取系統(tǒng)時間print getdate()- 獲取3天前的時間print dateadd(day, -3 , getdate()- 獲取3天后的時間pr

16、int dateadd(day, 3 , getdate()- 獲取3年前的時間print dateadd(year, -3 , getdate()- 獲取3年后的時間print dateadd(year, 3 , getdate()- 獲取3月后的時間print dateadd(month, 3 , getdate()- 獲取9小時后的時間print dateadd(hour, 9 , getdate()- 獲取9分鐘后的時間print dateadd(minute, 9 , getdate()- 獲取指定時間之間相隔多少年print datediff(year, '2005-01-

17、01', '2008-01-01')- 獲取指定時間之間相隔多少月print datediff(month, '2005-01-01', '2008-01-01')- 獲取指定時間之間相隔多少天print datediff(day, '2005-01-01', '2008-01-01')- 字符串合并print 'abc' + 'def'print 'abcder'print 'abc' + '456'print 'ab

18、c' + 456- 類型轉(zhuǎn)換print 'abc' + convert(varchar(10), 456)select title_id, type, price from titles- 字符串連接必須保證類型一致(以下語句執(zhí)行將會出錯)- 類型轉(zhuǎn)換select title_id + type + price from titles- 正確select title_id + type + convert(varchar(10), price) from titlesprint '123' + convert(varchar(3), 123)print

19、'123' + '123'print convert(varchar(12), '2005-09-01',110)- 獲取指定時間的特定部分print year(getdate()print month(getdate()print day(getdate()- 獲取指定時間的特定部分print datepart(year, getdate()print datepart(month, getdate()print datepart(day, getdate()print datepart(hh, getdate()print datepart(

20、mi, getdate()print datepart(ss, getdate()print datepart(ms, getdate()- 獲取指定時間的間隔部分- 返回跨兩個指定日期的日期和時間邊界數(shù)print datediff(year, '2001-01-01', '2008-08-08')print datediff(month, '2001-01-01', '2008-08-08')print datediff(day, '2001-01-01', '2008-08-08')print

21、datediff(hour, '2001-01-01', '2008-08-08')print datediff(mi, '2001-01-01', '2008-08-08')print datediff(ss, '2001-01-01', '2008-08-08')- 在向指定日期加上一段時間的基礎(chǔ)上，返回新的 datetime 值print dateadd(year, 5, getdate()print dateadd(month, 5, getdate()print dateadd(day,

22、5, getdate()print dateadd(hour, 5, getdate()print dateadd(mi, 5, getdate()print dateadd(ss, 5, getdate()- 其他print host_id()print host_name()print db_id('pubs')print db_name(5)- 利用系統(tǒng)函數(shù)作為默認值約束drop table tttcreate table ttt(stu_name varchar(12),stu_birthday datetime default (getdate()

23、alter table tttadd constraint df_ttt_stu_birthday default  (getdate() for stu_birthdayinsert into ttt values ('ANiu', '2005-04-01')insert into ttt values ('ANiu', getdate()insert into ttt values ('AZhu', default)sp_help tttselect * from ttt （4.2）自定義函數(shù)select

24、title_idfrom titles where type = 'business'select stuff(title_id,1,3,'ABB'), type from titles where type = 'business'select count(title_id) from titles where type = 'business'select title_id from titles where type = 'business'select au_id, count(title_id)from

25、titleauthorgroup by au_idSELECT dbo.authors.au_id, COUNT(dbo.titleauthor.title_id) AS '作品數(shù)量'FROM dbo.authors  left outer JOIN      dbo.titleauthor ON dbo.authors.au_id = dbo.titleauthor.au_idGROUP BY dbo.authors.au_idorder by '作品數(shù)量'- 自定義函數(shù)的引子（通過這個子查詢來引入函

26、數(shù)的作用）- 子查詢- 統(tǒng)計每個作者的作品數(shù)- 將父查詢中的作者編號傳入子查詢- 作為查詢條件利用聚合函數(shù)count統(tǒng)計其作品數(shù)量select au_lname,   (select count(title_id)  from titleauthor as ta  where ta.au_id = a.au_id ) as TitleCountfrom authors as aorder by TitleCount - 是否可以定義一個函數(shù)- 將作者編號作為參數(shù)統(tǒng)計其作品數(shù)量并將其返回select au_id, au_lname, d

27、bo.GetTitleCountByAuID(au_id) as TitleCount from authorsorder by TitleCount- 根據(jù)給定的作者編號獲取其相應(yīng)的作品數(shù)量create function GetTitleCountByAuID(au_id varchar(12)returns intbegin return (select count(title_id)   from titleauthor  where au_id = au_id)end - 利用函數(shù)來顯示每個作者的作品數(shù)量create proc pro_

28、CalTitleCountasselect au_id, au_lname, dbo.GetTitleCountByAuID(au_id) as TitleCount from authorsorder by TitleCountgo- 執(zhí)行存儲過程execute pro_CalTitleCount- vb中函數(shù)定義格式function GetTitleCountByAuID(au_id as string) as integer  . GetTitleCountByAuID = ?end function- SALES 作品銷售信息select * from s

29、ales- 根據(jù)書籍編號查詢其銷售記錄（其中，qty 表示銷量）select * from sales where title_id = 'BU1032'- 根據(jù)書籍編號統(tǒng)計其總銷售量（其中，qty 表示銷量）select sum(qty) from sales where title_id = 'BU1032'- 利用分組語句（group by），根據(jù)書籍編號統(tǒng)計每本書總銷售量（其中，qty 表示銷量）select title_id, sum(qty) from sales group by title_id- 是否可以考慮定義一個函數(shù)根據(jù)書籍編號來計算其總銷

30、售量- 然后，將其應(yīng)用到任何一條包含了書籍編號的查詢語句中select title_id, title, dbo.GetTotalSaleByTitleID(title_id) as TotalSalesfrom titlesorder by TotalSales- 定義一個函數(shù)根據(jù)書籍編號來計算其總銷售量create function GetTotalSaleByTitleID(tid varchar(24)returns intbegin return(select sum(qty) from sales where title_id = tid)end- 統(tǒng)計書籍銷量的前10位

31、- 其中，可以利用函數(shù)計算結(jié)果的別名作為排序子句的參照列select top 10 title_id, title, dbo.GetTotalSaleByTitleID(title_id) as TotalSalesfrom titlesorder by TotalSales desc- 根據(jù)書籍編號計算其銷量排名create function GetTheRankOfTitle(id varchar(20)returns intbegin return(select count(TotalSales)   from titles   wher

32、e ToalSales >(  select TotalSales   from titles   where title_id=id)end- 根據(jù)書籍編號計算其銷量排名select dbo.GetTheRankOfTitle('pc1035') from titlesselect count(title_id) + 1from titles where dbo.GetTotalSaleByTitleID(title_id) > dbo.GetTotalSaleByTitleID('pc1035&

33、#39;)- 刪除函數(shù)drop function GetRankByTitleId- 根據(jù)書籍編號計算其銷量排名create function GetRankByTitleId(tid varchar(24)returns intbegin return (select count(title_id) + 1  from titles   where dbo.GetTotalSaleByTitleID(title_id) > dbo.GetTotalSaleByTitleID(tid)end- 在查詢語句中利用函數(shù)統(tǒng)計每本書的總銷量和總排

34、名select title_id, title, dbo.GetTotalSaleByTitleID(title_id) as TotalSales, dbo.GetRankByTitleId(title_id) as TotalRankfrom titlesorder by TotalSales desc- 查看表結(jié)構(gòu)sp_help titles- 查看存儲過程的定義內(nèi)容sp_helptext GetRankByTitleIdsp_helptext sp_helptext sp_helptext xp_cmdshell- ORDER DETAILS 訂單詳細信息selec

35、t * from order details select * from order details where productid = 23- 根據(jù)產(chǎn)品編號在訂單詳細信息表中統(tǒng)計總銷售量select sum(quantity) from order details where productid = 23- 構(gòu)造一個函數(shù)根據(jù)產(chǎn)品編號在訂單詳細信息表中統(tǒng)計總銷售量create function GetTotalSaleByPID(Pid varchar(12)returns intbegin return(select sum(quantity) from order details

36、 where productid = Pid)endselect * from products- 在產(chǎn)品表中查詢，統(tǒng)計每一樣產(chǎn)品的總銷量select productid, productname, dbo.GetTotalSaleByPID(productid) from products- CREATE FUNCTION LargeOrderShippers ( FreightParm money )RETURNS OrderShipperTab TABLE   (    ShipperID    

37、int,    ShipperName   nvarchar(80),    OrderID       int,    ShippedDate   datetime,    Freight       money   )ASBEGIN   INSERT OrderShipper

38、Tab        SELECT S.ShipperID, S.CompanyName,               O.OrderID, O.ShippedDate, O.Freight        FROM Shippers AS S INNER JOIN Orders AS O  

39、0;           ON S.ShipperID = O.ShipVia        WHERE O.Freight > FreightParm   RETURNENDSELECT * FROM LargeOrderShippers( $500 )- 根據(jù)作者編號計算其所得版權(quán)費create function fun_RoyalTyper ( au_id id)returns intasbeg

40、in declare rt int select rt = sum(royaltyper) from titleauthor where au_id = au_id return (rt)endgoselect top 1 au_lname, au_fname, dbo.fun_RoyalTyper(au_id) as '版權(quán)費' from authorsorder by  dbo.fun_RoyalTyper(au_id) descgocreate function fun_MaxRoyalTyper_Au_id ()returns i

41、dasbegin  declare au_id id select au_id = au_id from authors order by  dbo.fun_RoyalTyper(au_id) return(au_id)endgoselect dbo.fun_MaxRoyalTyper_Au_id()goselect au_lname, au_fname, dbo.fun_RoyalTyper(au_id) as '版權(quán)稅'  from authorswhere au_id = dbo.fun_Ma

42、xRoyalTyper_Au_id()go(5)高級查詢 select title_id, price from titles- 查找最高價格select max(price) from titles- 查找最貴書籍的價格(排序)，如果存在多本價格最貴的書，此方法將會遺漏select top 1 title_id, price from titlesorder by price desc- 查找最貴書籍的價格(子查詢)select title_id, price from titleswhere price = (select max(price) from titles)- 查詢指

43、定出版社出版的書(連接)select p.pub_name as '出版社', t.title as '書籍名稱'from publishers as p join titles as t on p.pub_id = t.pub_idwhere pub_name = 'New Moon Books'- 查詢指定出版社出版的書(子查詢)select title from titles where pub_id = (select pub_id   from publishers   where pub_nam

44、e =  'New Moon Books')- 查詢指定出版社出版的書(分開查詢)select title from titles where pub_id = '0736'select pub_id from publishers where pub_name =  'New Moon Books'- 重點- 理解相關(guān)子查詢的基礎(chǔ)- select * from titles where type = 'business'select * from titles where type = 'busine

45、ss123'select * from titles where 1 = 1 - 在訂單表中尋找滿足以下條件的訂單編號以及相應(yīng)的客戶編號- 在詳細訂單表中存在對應(yīng)的訂單編號并且其中包含產(chǎn)品編號為23的產(chǎn)品- 然后將產(chǎn)品編號為23的產(chǎn)品訂購量返回判斷是否大于20USE northwindSELECT orderid, customeridFROM orders AS or1WHERE 20 < (SELECT quantity FROM order details AS od         

46、    WHERE or1.orderid = od.orderid              AND  ductid = 23)GOSELECT au_lname, au_fname FROM authors WHERE 100 IN  ( SELECT royaltyper FROM titleauthor  WHERE titleauthor.au_ID = authors.au

47、_id )  select authors.au_lname,authors.au_fnamefrom authors join  titleauthor on titleauthor.au_ID=authors.au_idwhere titleauthor.royaltyper =100 USE pubsSELECT au_lname, au_fnameFROM authorsWHERE au_id IN   (SELECT au_id   FROM titleauthor   WHERE title_

48、id IN      (SELECT title_id      FROM titles      WHERE type = 'popular_comp') select distinct t.type, a.au_lname, a.au_fnamefrom authors as a join titleauthor as ta on a.au_id = ta.au_id   join ti

49、tles as t on ta.title_id = t.title_idwhere t.type = 'business'- 查找類型為'business'或是'trad_cook'類型的書籍select * from titles where type = 'business'select * from titles where type = 'trad_cook'- 查找類型為'business'或是'trad_cook'類型的書籍(Or)select * from title

50、s where type = 'business' or type = 'trad_cook'- 查找類型為'business'或是'trad_cook'類型的書籍(In)select * from titles where type in ('business', 'trad_cook')- 查找來自'KS'或是'UT'的作者select au_lname, state from authors where state = 'KS'select au

51、_lname, state from authors where state = 'UT'- 查找來自'KS'或是'UT'的作者(Or)select au_lname, state from authors where state = 'UT' or state = 'KS'- 查找來自'KS'或是'UT'的作者(In)select au_lname, state from authors where state in ('UT', 'KS')sele

52、ct au_lname, state from authors where state not in ('UT', 'KS')- 查找出版了類型為'business'類型的書籍的出版社SELECT pub_id FROM titles WHERE type = 'business'SELECT pub_id,pub_nameFROM publishersWHERE pub_id IN ('1389', '0736')- 查找出版了類型為'business'類型的書籍的出版社(In和子

53、查詢)SELECT pub_id,pub_nameFROM publishersWHERE pub_id IN   (SELECT pub_id   FROM titles   WHERE type = 'business') SELECT title, advanceFROM titlesWHERE advance >    (    SELECT MAX(advance)    FROM publishers INNER

54、 JOIN titles ON       titles.pub_id = publishers.pub_id    WHERE pub_name = 'Algodata Infosystems'   )SELECT title, advanceFROM titlesWHERE advance > all   (    SELECT advance    FROM publishers INNE

55、R JOIN titles ON       titles.pub_id = publishers.pub_id    WHERE pub_name = 'Algodata Infosystems' and advance is not null   )declare i intset i = 12if i < null print 'DDDDD'else print 'XXXXX'  

56、60;SELECT advance    FROM publishers INNER JOIN titles ON       titles.pub_id = publishers.pub_id    WHERE pub_name = 'Algodata Infosystems' select title_id, price from titleswhere price > all(select price from titles where type

57、= 'business')select title_id, price from titleswhere price > (select max(price) from titles where type = 'business')select title_id, price from titleswhere price > any(select price from titles where type = 'business')select title_id, price from titleswhere price > (s

58、elect min(price) from titles where type = 'business')select price from titles where type = 'business'if exists(select * from titles where type = '123') print 'ZZZZZ'else  print 'BBBBB'if exists(select * from authors where city = 'Berkeley

59、9; and state ='UT') print 'Welcome'else print 'Bye-Bye'- 篩選出'business'以及'trad_cook'類型的書籍(聯(lián)合查詢)select title_id, type from titles where type = 'business'unionselect title_id, type from titles where type = 'trad_cook'- 統(tǒng)計'business

60、9;類型的書籍的總價(聯(lián)合查詢)select title, price from titles where type = 'business'unionselect '合計:', sum(price) from titles where type = 'business'- 統(tǒng)計所有書籍的類型剔除重復(fù)(Distinct)select distinct type from titles- 作者記錄的復(fù)制(Select Into)select * into au from authorsselect * from au- 查看數(shù)據(jù)表結(jié)構(gòu)(Select

61、 Into并沒有對數(shù)據(jù)表的約束進行復(fù)制)sp_help authorssp_help au- 分頁(子查詢的經(jīng)典應(yīng)用之一)- Jobs 職務(wù)信息表（pubs 數(shù)據(jù)庫）- 在實際項目中，顯示職務(wù)信息時，而職務(wù)信息量非常龐大，可能需要將其分為若干個頁面來顯示- 比如：每頁顯示4條記錄，那么，第一頁將顯示1，2，3，4，第二頁將顯示5，6，7，8。- 顯示所有信息SELECT * FROM jobs- 顯示前 4 信息select top 4 * from jobs- 顯示前 8 信息select top 8 * from jobs- 顯示前 12 信息select top 12 * from jo

62、bs- 尋找規(guī)律，每一頁的信息源于前（頁面大小 * 頁碼）條信息的反序結(jié)果的前 頁面大小 條記錄- 比如：第二頁就是前 8 條記錄的反序結(jié)果的前 4 條select top 4 * from (select top 8 * from jobs) as ttorder by job_id desc- 當然，對于期望按升序顯示查詢結(jié)果的要求可以對查詢結(jié)果進行再次排序select * from(select top 4 * from (select top 8 * from jobs) as ttorder by job_id desc) as sttorder by job_id- SQL 命令中

63、不支持在 select 的查詢列表中直接使用局部變量- 比如：select top PageSize * from jobs- 那么，可以考慮對sql命令進行拼裝，然后，利用系統(tǒng)存儲過程 sp_executesql 來執(zhí)行exec sp_executesql N'Select * from jobs'- 存儲過程的實現(xiàn)- 其中，CurrentPageSize用于確定最后一頁的頁面大小create proc proGetJobsByPageCurrentPageSize int,PageSize int,CurrentPage intasDeclare strSql nvarch

64、ar(400)set strSql = 'select * from  (select top ' + convert(nvarchar(4), CurrentPageSize) + ' *   from (select top ' + convert(nvarchar(4),(PageSize * CurrentPage) + ' * from jobs) as tt  order by job_id desc) as stt  order by job_id'ex

65、ec sp_executesql strSqlgo- 測試exec proGetJobsByPage 2, 4, 4 (6)存儲過程- 擴展存儲過程- 查詢系統(tǒng)目錄下文件信息xp_cmdshell 'dir *.*'- 啟動Windows系統(tǒng)服務(wù)xp_cmdshell 'net start iisadmin' (7)游標- 游標的五個基本操作步驟：- 聲明declare cur_titles cursorfor select title, price from titles- 打開open cur_titles- 提取fetch cur_ti

66、tlesfetch next from cur_titles- 關(guān)閉close cur_titles- 釋放deallocate cur_titles - 利用游標遍歷所有書籍信息，通過冒泡排序法進行比較，找出最高價格的書- 這一段為批處理版- 與批處理版相比，存儲過程版更方便調(diào)試以及代碼的重用- 聲明declare cur_titles cursorfor select title, price from titles- 打開open cur_titlesdeclare title varchar(80)declare price numeric(9,4)declare title_temp varchar(80)declare price_temp numeric(9,4)- 提取fetch cur_titles into title, pricefetch cur_titles into title_temp, price_tempwhile fetch_status = 0begin if price < price_temp begin  set price = price_te