SQLServer常用函数对比

1、SQLServer和Oracle的常用函数对比1.绝对值 S:select abs(-1) valueO:select abs(-1) value from dual2.取整(大) S:select ceiling(-1.001) value O:select ceil(-1.001) value from dual3.取整（小） S:select floor(-1.001) value O:select floor(-1.001) value from dual4.取整（截取）S:select cast(-1.002 as int) value O:select trunc(-1.002)

2、value from dual 5.四舍五入S:select round(1.23456,4) value 1.23460O:select round(1.23456,4) value from dual 1.23466.e为底的幂 S:select Exp(1) value 2.7182818284590451 O:select Exp(1) value from dual 2.718281827.取e为底的对数S:select log(2.7182818284590451) value 1O:select ln(2.7182818284590451) value from dual; 18

3、.取10为底对数S:select log10(10) value 1O:select log(10,10) value from dual; 19.取平方S:select SQUARE(4) value 16O:select power(4,2) value from dual 1610.取平方根S:select SQRT(4) value 2O:select SQRT(4) value from dual 211.求任意数为底的幂S:select power(3,4) value 81O:select power(3,4) value from dual 8112.取随机数S:select

4、rand() value O:select sys.dbms_random.value(0,1) value from dual;13.取符号S:select sign(-8) value -1O:select sign(-8) value from dual -1-数学函数14.圆周率S:Select PI() value 3.1415926535897931O:不知道15.sin,cos,tan 参数都以弧度为单位例如：select sin(PI()/2) value 得到1（SQLServer）16.Asin,Acos,Atan,Atan2 返回弧度17.弧度角度互换(SQLServer

5、，Oracle不知道)DEGREES：弧度-角度RADIANS：角度-弧度-数值间比较18. 求集合最大值S:select max(value) value from (select 1 valueunionselect -2 valueunionselect 4 valueunionselect 3 value)aO:select greatest(1,-2,4,3) value from dual19. 求集合最小值S:select min(value) value from (select 1 valueunionselect -2 valueunionselect 4 valueuni

6、onselect 3 value)aO:select least(1,-2,4,3) value from dual20.如何处理null值(F2中的null以10代替)S:select F1,IsNull(F2,10) value from TblO:select F1,nvl(F2,10) value from Tbl-数值间比较21.求字符序号S:select ascii('a') valueO:select ascii('a') value from dual22.从序号求字符S:select char(97) valueO:select chr(97)

7、 value from dual23.连接S:select '11'+'22'+'33' valueO:select CONCAT('11','22')|33 value from dual23.子串位置 -返回3S:select CHARINDEX('s','sdsq',2) value O:select INSTR('sdsq','s',2) value from dual23.模糊子串的位置 -返回2,参数去掉中间%则返回7S:select pa

8、tindex('%d%q%','sdsfasdqe') value O:oracle没发现，但是instr可以通过第四霾问刂瞥鱿执问?BR>select INSTR('sdsfasdqe','sd',1,2) value from dual 返回624.求子串S:select substring('abcd',2,2) value O:select substr('abcd',2,2) value from dual25.子串代替 返回aijklmnefS:Select STUFF('

9、abcdef', 2, 3, 'ijklmn') valueO:Select Replace('abcdef', 'bcd', 'ijklmn') value from dual26.子串全部替换S:没发现O:select Translate('fasdbfasegas','fa','我' ) value from dual27.长度S:len,datalengthO:length28.大小写转换 lower,upper29.单词首字母大写S:没发现O:select INIT

10、CAP('abcd dsaf df') value from dual30.左补空格（LPAD的第一个参数为空格则同space函数）S:select space(10)+'abcd' valueO:select LPAD('abcd',14) value from dual31.右补空格（RPAD的第一个参数为空格则同space函数）S:select 'abcd'+space(10) valueO:select RPAD('abcd',14) value from dual32.删除空格S:ltrim,rtrimO

11、:ltrim,rtrim,trim33. 重复字符串S:select REPLICATE('abcd',2) value O:没发现34.发音相似性比较(这两个单词返回值一样，发音相同)S:Select SOUNDEX ('Smith'), SOUNDEX ('Smythe')O:Select SOUNDEX ('Smith'), SOUNDEX ('Smythe') from dualSQLServer中用Select DIFFERENCE('Smithers', 'Smythers

12、9;) 比较soundex的差返回0-4，4为同音，1最高-日期函数35.系统时间S:select getdate() valueO:select sysdate value from dual36.前后几日直接与整数相加减37.求日期S:select convert(char(10),getdate(),20) valueO:select trunc(sysdate) value from dualselect to_char(sysdate,'yyyy-mm-dd') value from dual38.求时间S:select convert(char(8),getdate

13、(),108) valueO:select to_char(sysdate,'hh24:mm:ss') value from dual39.取日期时间的其他部分S:DATEPART 和 DATENAME 函数 （第一个参数决定） O:to_char函数 第二个参数决定参数-下表需要补充year yy, yyyy quarter qq, q (季度)month mm, m (m O无效)dayofyear dy, y (O表星期)day dd, d (d O无效)week wk, ww (wk O无效)weekday dw (O不清楚)Hour hh,hh12,hh24 (hh1

14、2,hh24 S无效)minute mi, n (n O无效)second ss, s (s O无效)millisecond ms (O无效)-40.当月最后一天S:不知道O:select LAST_DAY(sysdate) value from dual41.本星期的某一天（比如星期日）S:不知道O:Select Next_day(sysdate,7) vaule FROM DUAL;42.字符串转时间S:可以直接转或者select cast('2004-09-08'as datetime) valueO:Select To_date('2004-01-05 22:0

15、9:38','yyyy-mm-dd hh24-mi-ss') vaule FROM DUAL;43.求两日期某一部分的差（比如秒）S:select datediff(ss,getdate(),getdate()+12.3) valueO:直接用两个日期相减（比如d1-d2=12.3）Select (d1-d2)*24*60*60 vaule FROM DUAL;44.根据差值求新的日期（比如分钟）S:select dateadd(mi,8,getdate() valueO:Select sysdate+8/60/24 vaule FROM DUAL;45.求不同时区时间

16、S:不知道O:Select New_time(sysdate,'ydt','gmt' ) vaule FROM DUAL;-时区参数,北京在东8区应该是Ydt-AST ADT 大西洋标准时间BST BDT 白令海标准时间CST CDT 中部标准时间EST EDT 东部标准时间GMT 格林尼治标准时间HST HDT 阿拉斯加夏威夷标准时间MST MDT 山区标准时间NST 纽芬兰标准时间PST PDT 太平洋标准时间YST YDT YUKON标准时间配置 SQL Server 数据库EXEC sp_dboption 'pubs', 'rea

17、d only', 'True'此选项把数据库 “pubs” 设置为只读。 EXEC sp_dboption 'pubs' autoshrink true此选项把符合条件的“pubs” 数据库文件设置为自动周期性收缩。 EXEC sp_dboption 'pubs' single user此命令每次只允许一个用户访问数据库。 DBCC SHRINKDATABASE(PUBS, 10)会减小“pubs”数据库中文件的大小，并允许有 10% 的可用空间。 使用 T-SQL 创建表 create table MyTable ( stdID int

18、, stdName varchar(50) ) 自定义数据类型 EXEC sp_addtype City, 'nvarchar(15)', NULLEXEC sp_addtype PostCode, 'nvarchar(6)', NULLEXEC sp_addtype NCode, 'nvarchar(18)', NULL 删除自定义数据类型EXEC sp_droptype city 使用 T-SQL 创建表CREATE TABLE Categories ( CategoryID int IDENTITY(1,1), CategoryName n

19、varchar(15) NOT NULL, Description ntext NULL, Picture image NULL) 实体完整性实现 l 主键约束CREATE TABLE jobs(Job_id smallint PRIMARY KEY,job_desc varchar(50) NOT NULL) l 唯一约束CREATE TABLE jobs(Job_id smallint UNIQUE) l 标识列CREATE TABLE jobs(Job_id smallint IDENTIRY（2,1） PRIMARY KEY) l Uniqueidentifier数据类型和NEWID

20、函数CREATE TABLE Customer (CustID uniqueidentifier NOT NULL DEFAULT NEWID(),CustName char(30) NOT NULL) INSERT Customer VALUES (NEWID(),'ASB') l 引用完整性实现 ALTER TABLE dbo.Orders ADD CONSTRAINT FK_Orders_Customers FOREIGN KEY (CustomerID) REFERENCES dbo.Customers(CustomerID) l 更新表结构ALTER TABLE My

21、Table ALTER COLUMN NullCOl NVARCHAR(20) NOT NULLALTER TABLE jobs ADD HIRE_DATE DATETIMEALTER TABLE Doc_ED DROP COLUMN Column_BALTER TABLE Doc_ED WITH NOCHECK ADD CONSTRAINT Exd_Check CHECK (Column_a > 1) l 在已有字段中增加标识约束时，必须先删除该字段，再新建字段。alter table mytable drop column userid alter table mytable add

22、 userid int identity(1,1)l 删除表DROP TABLE Airlines_Master l DEFAULT约束USE NorthwindCREATE TABLE ABC (ASD int Default 8, ASDE varchar(20) Default 'UNKNOWN') USE NorthwindALTER TABLE dbo.Customers ADD CONSTRAINT DF_contactname DEFAULT 'UNKNOWN' FOR ContactName l CHECK约束CREATE TABLE ABCD

23、(ASD int CHECK(ASD <100) , ASDE varchar(80) Default 'UNKNOWN') USE NorthwindALTER TABLE Employees ADD CONSTRAINT CK_birthdateCHECK (BirthDate > '01-01-1900' AND BirthDate < 01-01-2010)PRIMARY KEY约束CREATE TABLE AWC (ASD int CHECK(ASD <100) PRIMARY KEY, ASDE varchar(80) Def

24、ault 'UNKNOWN') USE Northwind ALTER TABLE Customers ADD CONSTRAINT PK_Customers PRIMARY KEY (CustomerID) l UNIQUE约束CREATE TABLE AAC (ASD int CHECK(ASD <100) PRIMARY KEY, ASDE int UNIQUE) USE NorthwindALTER TABLE Suppliers ADD CONSTRAINT U_CompanyName UNIQUE (CompanyName) l FOREIGN KEY约束CR

25、EATE TABLE ACC (ASD int CHECK(ASD <100) PRIMARY KEY, ASDE int FOREIGN KEY REFERENCES AAC(ASD) USE NorthwindALTER TABLE Orders WITH NOCHECK ADD CONSTRAINT FK_Or_Cu FOREIGN KEY (CustomerID) REFERENCES Customers(CustomerID) 通配符通配符 解释 例子'_' 一个字符 Branch Like 'L_'% 任意长度 Route_Code Like

26、'AMS-%' 指定范围内 Airbusno Like 'AB01-5 ' 不在括号中 Airbusno Like 'AB01-5 ' 向表中插入数据 语法：INSERT INTO 表名 （字段列表）VALUES （值列表） 例：1. 插入指定值的一条记录INSERT INTO MyTable (PriKey, Description) VALUES (123, 'A description of part 123.') 2. 从查询中获得数据（多条）INSERT INTO MyTable (PriKey, Description

27、) SELECT ForeignKey, Description FROM SomeView 更新数据行 语法：UPDATE 表名 SET 字段名 = 新值， WHERE 条件 例： UPDATE TITLES SET Price = Price + 0.25*Price Where Title_ID = TC777 联接：根据表之间的逻辑关系搜索多表中的数据1 内联接SELECT FROM 表1 INNER JOIN 表2 ON 表1.字段1=表2.字段1 WHERE 条件 例：UPDATE TITLES SET Price = Price + 10 From Titles INNER JO

28、IN TitleAuthor ON Titles.Title_IS = TitleAuthor.Title_ID WHERE Titles.Title = 'SuShi,AnyOne?'2 外联接左联接：左表与右表相联接的数据和左表的其他数据：SELECT FROM 表1 LEFT JOIN 表2 ON 表1.字段1=表2.字段1 WHERE 条件 例：UPDATE TITLES SET Price = Price + 10 From Titles LEFT OUTER JOIN TitleAuthor ON Titles.Title_IS = TitleAuthor.Titl

29、e_ID WHERE Titles.Title = 'SuShi,AnyOne?' 右联接：右表与左表相联接的数据和右表的其他数据：SELECT FROM 表1 RIGHT JOIN 表2 ON 表1.字段1=表2.字段1 WHERE 条件 例：UPDATE TITLES SET Price = Price + 10 From Titles RIGHT OUTER JOIN TitleAuthor ON Titles.Title_IS = TitleAuthor.Title_ID WHERE Titles.Title = 'SuShi,AnyOne?' 全联接：

30、右表与左表相联接的数据及右表和左表的其他数据：SELECT FROM 表1 FULL JOIN 表2 ON 表1.字段1=表2.字段1WHERE 条件 3 自联接：表与其自身联接SELECT FROM 表1 as A JOIN 表1 as B ON A.字段1=B.字段2 WHERE 条件 删除数据 DELETE FROM 表 WHERE 条件 TRUNCATE TABLE 表 -删除表中所有的记录，但不记日志 查询数据1. 数据库和所有者限定SELECT * FROM Northwind.dbo.Shippers 2. 查询中使用常量和运算符SELECT title_id +':&#

31、39;+ title + '->' + type As MyTitle FROM titles 3. 聚合函数SELECT productid ,SUM(quantity) AS total_quantity FROM orderhist GROUP BY productid 显示所有type的值，并按type分组求平均值SELECT type, AVG(price) FROM titles WHERE royalty = 10 GROUP BY ALL type 条件中带有聚合函数的，要用Having 子句SELECT productid, SUM(quantity)

32、AS total_quantity FROM orderhist GROUP BY productid HAVING SUM(quantity)>=30 4. 模糊查询 WHERE companyname LIKE '%Restaurant% WHERE fax IS NULL WHERE country IN ('Japan', 'Italy') WHERE unitprice BETWEEN 10 AND 201. 说明：复制表(只复制结构,源表名：a 新表名：b) SQL: select * into b from a where 1<

33、>1 2.说明：拷贝表(拷贝数据,源表名：a 目标表名：b) SQL: insert into b(a, b, c) select d,e,f from b; 3.说明：显示文章、提交人和最后回复时间 SQL: select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 4.说明：外连接查询(表名1：a 表名2：b) SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a L

34、EFT OUTER JOIN b ON a.a = b.c 5.说明：日程安排提前五分钟提醒 SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate()>5 6.说明：两张关联表，删除主表中已经在副表中没有的信息 SQL: delete from info where not exists ( select * from infobz where info.infid=infobz.infid ) 说明：- SQL: SELECT A.NUM, A.NAME, B.UPD_DATE, B.PREV_UPD

35、_DATE FROM TABLE1, (SELECT X.NUM, X.UPD_DATE, Y.UPD_DATE PREV_UPD_DATE FROM (SELECT NUM, UPD_DATE, INBOUND_QTY, STOCK_ONHAND FROM TABLE2 WHERE TO_CHAR(UPD_DATE,'YYYY/MM') = TO_CHAR(SYSDATE, 'YYYY/MM') X, (SELECT NUM, UPD_DATE, STOCK_ONHAND FROM TABLE2 WHERE TO_CHAR(UPD_DATE,'YYYY

36、/MM') = TO_CHAR(TO_DATE(TO_CHAR(SYSDATE, 'YYYY/MM') | '/01','YYYY/MM/DD') - 1, 'YYYY/MM') ) Y, WHERE X.NUM = Y.NUM （+） AND X.INBOUND_QTY + NVL(Y.STOCK_ONHAND,0) <> X.STOCK_ONHAND ) B WHERE A.NUM = B.NUM 说明：- SQL: select * from studentinfo where not exists(se

37、lect * from student where studentinfo.id=student.id) and 系名称='"&strdepartmentname&"' and 专业名称='"&strprofessionname&"' order by 性别,生源地,高考总成绩 7.说明： 从数据库中去一年的各单位电话费统计(电话费定额贺电化肥清单两个表来源） SQL: SELECT a.userper, a.tel, a.standfee, TO_CHAR(a.telfeedate, &#

38、39;yyyy') AS telyear, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '01', a.factration) AS JAN, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '02', a.factration) AS FRI, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '03', a.factration) AS MAR, SUM(decode(TO_CHAR(a.t

39、elfeedate, 'mm'), '04', a.factration) AS APR, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '05', a.factration) AS MAY, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '06', a.factration) AS JUE, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '07', a.factra

40、tion) AS JUL, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '08', a.factration) AS AGU, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '09', a.factration) AS SEP, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '10', a.factration) AS OCT, SUM(decode(TO_CHAR(a.telfeedate, &

41、#39;mm'), '11', a.factration) AS NOV, SUM(decode(TO_CHAR(a.telfeedate, 'mm'), '12', a.factration) AS DEC FROM (SELECT a.userper, a.tel, a.standfee, b.telfeedate, b.factration FROM TELFEESTAND a, TELFEE b WHERE a.tel = b.telfax) a GROUP BY a.userper, a.tel, a.standfee, TO_

42、CHAR(a.telfeedate, 'yyyy') 8.说明：四表联查问题： SQL: select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where . 9.说明：得到表中最小的未使用的ID号 SQL: SELECT (CASE WHEN EXISTS(SELECT * FROM Handle b WHERE b.HandleID = 1) THEN MIN(HandleID) + 1 ELSE 1 END) as HandleI

43、D FROM Handle WHERE NOT HandleID IN (SELECT a.HandleID - 1 FROM Handle a)9.SQL语句技巧9.1、一个SQL语句的问题:行列转换select * from v_temp上面的视图结果如下:user_name role_name-系统管理员 管理员 feng 管理员 feng 一般用户 test 一般用户 想把结果变成这样:user_name role_name-系统管理员 管理员 feng 管理员,一般用户 test 一般用户=create table a_test(name varchar(20),role2 varc

44、har(20)insert into a_test values('李','管理員')insert into a_test values('張','管理員')insert into a_test values('張','一般用戶')insert into a_test values('常','一般用戶')create function join_str(content varchar(100)returns varchar(2000)asbegindeclare st

45、r varchar(2000)set str=''select str=str+','+rtrim(role2) from a_test where name=contentselect str=right(str,len(str)-1)return strendgo-调用：select name,dbo.join_str(name) role2 from a_test group by name-select distinct name,dbo.uf_test(name) from a_test9.2、求助！快速比较结构相同的两表结构相同的两表，一表有记录3万

46、条左右，一表有记录2万条左右，我怎样快速查找两表的不同记录？=给你一个测试方法，从northwind中的orders表取数据。select * into n1 from ordersselect * into n2 from ordersselect * from n1select * from n2-添加主键，然后修改n1中若干字段的若干条alter table n1 add constraint pk_n1_id primary key (OrderID)alter table n2 add constraint pk_n2_id primary key (OrderID)select O

47、rderID from (select * from n1union select * from n2) a group by OrderID having count(*) > 1应该可以，而且将不同的记录的ID显示出来。下面的适用于双方记录一样的情况，select * from n1 where orderid in(select OrderID from (select * from n1union select * from n2) a group by OrderID having count(*) > 1) 至于双方互不存在的记录是比较好处理的-删除n1,n2中若干条记

48、录delete from n1 where orderID in ('10728','10730')delete from n2 where orderID in ('11000','11001')-*- 双方都有该记录却不完全相同select * from n1 where orderid in(select OrderID from (select * from n1union select * from n2) a group by OrderID having count(*) > 1)union-n2中存在但在n1

49、中不存的在10728,10730select * from n1 where OrderID not in (select OrderID from n2)union-n1中存在但在n2中不存的在11000,11001select * from n2 where OrderID not in (select OrderID from n1)9.3、四种方法取表里n到m条纪录：1.select top m * into 临时表(或表变量) from tablename order by columnname - 将top m笔插入set rowcount nselect * from 表变量 o

50、rder by columnname desc2.select top n * from (select top m * from tablename order by columnname) aorder by columnname desc3.如果tablename里没有其他identity列，那么：select identity(int) id0,* into #temp from tablename取n到m条的语句为：select * from #temp where id0 >=n and id0 <= m如果你在执行select identity(int) id0,*

51、into #temp from tablename这条语句的时候报错,那是因为你的DB中间的select into/bulkcopy属性没有打开要先执行：exec sp_dboption 你的DB名字,'select into/bulkcopy',true4.如果表里有identity属性，那么简单：select * from tablename where identitycol between n and m 5.如何删除一个表中重复的记录？create table a_dist(id int,name varchar(20)insert into a_dist value

52、s(1,'abc')insert into a_dist values(1,'abc')insert into a_dist values(1,'abc')insert into a_dist values(1,'abc')exec up_distinct 'a_dist','id'select * from a_distcreate procedure up_distinct(t_name varchar(30),f_key varchar(30)-f_key表示是分組字段即主鍵字段asbegin

53、declare max integer,id varchar(30) ,sql varchar(7999) ,type integerselect sql = 'declare cur_rows cursor for select '+f_key+' ,count(*) from ' +t_name +' group by ' +f_key +' having count(*) > 1'exec(sql)open cur_rows fetch cur_rows into id,max while fetch_status=0

54、 begin select max = max -1 set rowcount max select type = xtype from syscolumns where id=object_id(t_name) and name=f_keyif type=56select sql = 'delete from '+t_name+' where ' + f_key+' = '+ id if type=167select sql = 'delete from '+t_name+' where ' + f_key+&#

55、39; = '+''''+ id +'''' exec(sql)fetch cur_rows into id,max end close cur_rows deallocate cur_rowsset rowcount 0endselect * from systypesselect * from syscolumns where id = object_id('a_dist')9.4.查询数据的最大排序问题（只能用一条语句写） CREATE TABLE hard (qu char (11) ,co char (11) ,je numeric(3, 0) insert into hard values ('A','1',3)insert into hard values ('A','2',4)insert into hard values ('A','4',2)insert into