sql数据库命令大全

1、公告： HYPERLINK http:/forum./SList/blogSupport t _blank 意见反馈 HYPERLINK /blogdevteam t _blank 官方博客 sql数据库命令大全 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) val

2、ue 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) 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 2.7

3、18281827.取e为底的对数S:select log(2.7182818284590451) value 1O:select ln(2.7182818284590451) value from dual; 18.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) val

4、ue 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 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,

5、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，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 fr

6、om dual19. 求集合最小值S:select min(value) value from (select 1 valueunionselect -2 valueunionselect 4 valueunionselect 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) va

7、lueO:select ascii(a) value from dual22.从序号求字符S:select char(97) valueO:select chr(97) 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 patindex

8、(%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?BRselect 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(abcdef, 2, 3, ijklmn) valueO:Select Replace(abcdef, bcd, ijklmn) value from

9、 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 INITCAP(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

10、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: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Sele

11、ct DIFFERENCE(Smithers, Smythers) 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 conv

12、ert(char(8),getdate(),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,h

13、h24 (hh12,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(2004-09-08as datetime) valueO:Select To_date(2004-01-05 22:09:38,yyy

14、y-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S:不知道O:Select New_time(

15、sysdate,ydt,gmt ) vaule FROM DUAL;时区参数,北京在东8区应该是YdtAST 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, read only, True此选项把数据库 “pubs” 设置为只读。EXEC sp_dboption pubs autos

16、hrink 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, stdName varchar(50) )自定义数据类型 EXEC sp_addtype City, nvarchar(15), NULLEXEC sp_addtype PostCode, nv

17、archar(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 nvarchar(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_des

18、c 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 函数CREATE TABLE Customer (CustID uniqueidentifier NOT NULL DEFAULT NEWID(),CustName char(30) NOT NULL)INSERT Customer VALUES (NEWID(),ASB

19、)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 MyTable ALTER COLUMN NullCOl NVARCHAR(20) NOT NULLALTER TABLE jobs ADD HIRE_DATE DATETIMEALTER TABLE Doc_ED DROP COLUMN Column_BALTER TABLE Doc_ED WITH

20、 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 userid int identity(1,1)l 删除表DROP TABLE Airlines_Masterl DEFAULT约束USE NorthwindCREATE TABLE ABC (ASD int Default 8, ASDE varchar(20) Default UNKNOWN)USE

21、NorthwindALTER TABLE dbo.Customers ADD CONSTRAINT DF_contactname DEFAULT UNKNOWN FOR ContactName l CHECK约束CREATE TABLE ABCD (ASD int CHECK(ASD 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) Default UNKNOWN)USE Northwind ALTER TA

22、BLE 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CREATE TABLE ACC (ASD int CHECK(ASD + type As MyTitle FR

23、OM titles3. 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) AS total_quantity FROM orderhistGROUP BY productid

24、HAVING SUM(quantity)=304. 模糊查询 WHERE companyname LIKE %Restaurant%WHERE fax IS NULLWHERE 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 11 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、

25、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 LEFT 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,

26、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_DATE FROM TABLE1, (SELECT X.NUM, X.UPD_DATE, Y.UPD_DATE PREV_UPD_DATE FROM (SELECT NUM, UPD_DATE, INBOUND_

27、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/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 + NV

28、L(Y.STOCK_ONHAND,0) X.STOCK_ONHAND ) B WHERE A.NUM = B.NUM 说明：- SQL: select * from studentinfo where not exists(select * 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

29、a.userper, a.tel, a.standfee, TO_CHAR(a.telfeedate, 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.telfeedate, mm),

30、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.factration) AS JUL, SUM(decode(TO_CHAR(a.telfeedate, mm), 08, a.factration) AS AGU, SUM(decode(TO_CHAR

31、(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, 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.fact

32、ration FROM TELFEESTAND a, TELFEE b WHERE a.tel = b.telfax) a GROUP BY a.userper, a.tel, a.standfee, TO_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 EXIST

33、S(SELECT * FROM Handle b WHERE b.HandleID = 1) THEN MIN(HandleID) + 1 ELSE 1 END) as HandleID 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

34、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 varchar(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)asbegin

35、declare str 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3万条左右，一表有记录2

36、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 OrderID fro

37、m (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中若干条记录delete from n1 wher

38、e 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中不存的在10728,10730select * from n1 where OrderID not in (select Ord

39、erID 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 order by columnname desc2.select top n * from (select top m * from

40、 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 1exec(sql)open cur_rows fetch cur_rows into id,max while fetch_status=0 begin select max = max -1 set rowcoun

41、t 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+ = + id + exec(sql)fetch cur_rows into id,max end close cur_rows deallocate cur_rowsset rowc

42、ount 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 hard values (A,6,9)in

43、sert into hard values (B,1,4)insert into hard values (B,2,5)insert into hard values (B,3,6)insert into hard values (C,3,4)insert into hard values (C,6,7)insert into hard values (C,2,3)要求查询出来的结果如下：qu co je A 6 9A 2 4B 3 6B 2 5C 6 7C 3 4就是要按qu分组，每组中取je最大的前2位！而且只能用一句sql语句！select * from hard a where je

44、in (select top 2 je from hard b where a.qu=b.qu order by je) 9.5.求删除重复记录的sql语句？ 怎样把具有相同字段的纪录删除，只留下一条。例如，表test里有id,name字段如果有name相同的记录 只留下一条，其余的删除。name的内容不定，相同的记录数不定。有没有这样的sql语句？=A:一个完整的解决方案：将重复的记录记入temp1表:select 标志字段id,count(*) into temp1 from 表名group by 标志字段idhaving count(*)12、将不重复的记录记入temp1表:insert

45、 temp1select 标志字段id,count(*) from 表名group by 标志字段idhaving count(*)=13、作一个包含所有不重复记录的表：select * into temp2 from 表名where 标志字段id in(select 标志字段id from temp1)4、删除重复表:delete 表名5、恢复表：insert 表名select * from temp26、删除临时表:drop table temp1drop table temp2=B:create table a_dist(id int,name varchar(20)insert int

46、o a_dist values(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,idselect * 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asbegindeclare max integer,id varchar(30) ,sql varcha

47、r(7999) ,type integerselect sql = declare cur_rows cursor for select +f_key+ ,count(*) from +t_name + group by +f_key + having count(*) 1exec(sql)open cur_rows fetch cur_rows into id,max while fetch_status=0 begin select max = max -1 set rowcount max select type = xtype from syscolumns where id=obje

48、ct_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+ = + id + exec(sql)fetch cur_rows into id,max end close cur_rows deallocate cur_rowsset rowcount 0endselect * from systypesselect * from syscolumns

49、 where id = object_id(a_dist)10.1. 行列转换-普通 假设有张学生成绩表(CJ)如下 Name Subject Result 张三 语文 80 张三 数学 90 张三 物理 85 李四 语文 85 李四 数学 92 李四 物理 82 想变成 姓名 语文 数学 物理 张三 80 90 85 李四 85 92 82 declare sql varchar(4000) set sql = select Name select sql = sql + ,sum(case Subject when +Subject+ then Result end) +Subject+

50、from (select distinct Subject from CJ) as a select sql = sql+ from test group by name exec(sql) 10.2. 行列转换-合并 有表A, id pid 1 1 1 2 1 3 2 1 2 2 3 1 如何化成表B: id pid 1 1,2,3 2 1,2 3 1 创建一个合并的函数 create function fmerg(id int) returns varchar(8000) as begin declare str varchar(8000) set str= select str=str+

51、,+cast(pid as varchar) from 表A where id=id set str=right(str,len(str)-1) return(str) End go -调用自定义函数得到结果 select distinct id,dbo.fmerg(id) from 表A 10.3. 如何取得一个数据表的所有列名 方法如下：先从SYSTEMOBJECT系统表中取得数据表的SYSTEMID,然后再SYSCOLUMN表中取得该数据表的所有列名。 SQL语句如下： declare objid int,objname char(40) set objname = tablename

52、select objid = id from sysobjects where id = object_id(objname) select Column_name = name from syscolumns where id = objid order by colid 是不是太简单了？ 呵呵 不过经常用阿. 10.4. 通过SQL语句来更改用户的密码 修改别人的,需要sysadmin role EXEC sp_password NULL, newpassword, User 如果帐号为SA执行EXEC sp_password NULL, newpassword, sa 10.5. 怎么判

53、断出一个表的哪些字段不允许为空？ select COLUMN_NAME from INFORMATION_SCHEMA.COLUMNS where IS_NULLABLE=NO and TABLE_NAME=tablename 10.6. 如何在数据库里找到含有相同字段的表？ a. 查已知列名的情况 SELECT as TableName, as columnname From syscolumns a INNER JOIN sysobjects b ON a.id=b.id AND b.type=U AND =你的字段名字 b. 未知列名查所有在不同表出现过的列名 Select As tab

54、lename, As columnname From syscolumns s1, sysobjects o Where s1.id = o.id And o.type = U And Exists ( Select 1 From syscolumns s2 Where = And s1.id s2.id ) 10.7. 查询第xxx行数据 假设id是主键： select * from (select top xxx * from yourtable) aa where not exists(select 1 from (select top xxx-1 * from yourtable) b

55、b where aa.id=bb.id) 如果使用游标也是可以的 fetch absolute number from cursor_name 行数为绝对行数 10.8. SQL Server日期计算 a. 一个月的第一天 SELECT DATEADD(mm, DATEDIFF(mm,0,getdate(), 0) b. 本周的星期一 SELECT DATEADD(wk, DATEDIFF(wk,0,getdate(), 0) c. 一年的第一天 SELECT DATEADD(yy, DATEDIFF(yy,0,getdate(), 0) d. 季度的第一天 SELECT DATEADD(qq

56、, DATEDIFF(qq,0,getdate(), 0) e. 上个月的最后一天 SELECT dateadd(ms,-3,DATEADD(mm, DATEDIFF(mm,0,getdate(), 0) f. 去年的最后一天 SELECT dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate(), 0) g. 本月的最后一天 SELECT dateadd(ms,-3,DATEADD(mm, DATEDIFF(m,0,getdate()+1, 0) h. 本月的第一个星期一 select DATEADD(wk, DATEDIFF(wk,0, datea

57、dd(dd,6-datepart(day,getdate(),getdate() ), 0) i. 本年的最后一天 SELECT dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate()+1, 0)。 11.1.获取表结构把 sysobjects 替换 成 tablename 即可 SELECT CASE IsNull(I.name, ) When Then Else * End as IsPK, Object_Name(A.id) as t_name, A.name as c_name, IsNull(SubString(M.text, 1, 254

58、), ) as pbc_init, T.name as F_DataType, CASE IsNull(TYPEPROPERTY(T.name, Scale), ) WHEN Then Cast(A.prec as varchar) ELSE Cast(A.prec as varchar) + , + Cast(A.scale as varchar) END as F_Scale, A.isnullable as F_isNullAble FROM Syscolumns as A JOIN Systypes as T ON (A.xType = T.xUserType AND A.Id = O

59、bject_id(sysobjects) ) LEFT JOIN ( SysIndexes as I JOIN Syscolumns as A1 ON ( I.id = A1.id and A1.id = object_id(sysobjects) and (I.status & 0 x800) = 0 x800 AND A1.colid 0 then else end) N主键, N类型, a.length N占用字节数, COLUMNPROPERTY(a.id,PRECISION) as N长度, isnull(COLUMNPROPERTY(a.id,Scale),0) as N小数位数,

60、 (case when a.isnullable=1 then else end) N允许空, isnull(e.text,) N默认值, isnull(g.value,) AS N字段说明 FROM syscolumns a left join systypes b on a.xtype=b.xusertype inner join sysobjects d on a.id=d.id and d.xtype=U and dtproperties left join syscomments e on a.cdefault=e.id left join sysproperties g on a.