SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 o'Uaz*-po
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一、基础 {\SJr:
1、说明:创建数据库 +9tm9<F8
CREATE DATABASE database-name &=KNKE`
2、说明:删除数据库 Hv>16W$_
drop database dbname *-zOQ=Y
3、说明:备份sql server ".Z1CBM(
--- 创建 备份数据的 device <kmH^viX
USE master (= T%eJ61
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ytWTJ>L
--- 开始 备份 M6j!_0j
BACKUP DATABASE pubs TO testBack S4salpz
4、说明:创建新表 'l&),]|$)
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) &e-MOM2&
根据已有的表创建新表: #Yqj27&
A:create table tab_new like tab_old (使用旧表创建新表) <r8sZrY
B:create table tab_new as select col1,col2... from tab_old definition only kn^?.^dVX
5、说明:删除新表 hB!>*AsG
drop table tabname l2&s4ERqSm
6、说明:增加一个列 VJ8"Q
Alter table tabname add column col type ]1^F
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 "1-gMob
7、说明:添加主键: Alter table tabname add primary key(col) M<%g )jn_
说明:删除主键: Alter table tabname drop primary key(col) f4b`*KGf
8、说明:创建索引:create [unique] index idxname on tabname(col....) snH9@!cG8
删除索引:drop index idxname 77]6_
注:索引是不可更改的,想更改必须删除重新建。 HW@r1[Y
9、说明:创建视图:create view viewname as select statement )Rlh[Y& r
删除视图:drop view viewname 1 m>x5Dbk!
10、说明:几个简单的基本的sql语句 68!W~%?pR
选择:select * from table1 where 范围 &4dh $w]q
插入:insert into table1(field1,field2) values(value1,value2) 'Avp16zg
删除:delete from table1 where 范围 qubyZ8hx
更新:update table1 set field1=value1 where 范围 S5,y!K]C~
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! <
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排序:select * from table1 order by field1,field2 [desc] cl'#nLPz;
总数:select count as totalcount from table1 k;fy8
求和:select sum(field1) as sumvalue from table1 ~+HZQv3Y
平均:select avg(field1) as avgvalue from table1 5C G
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最大:select max(field1) as maxvalue from table1 ~vL`[JiK
最小:select min(field1) as minvalue from table1 O1
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11、说明:几个高级查询运算词 ZQVr]/W^r
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A: UNION 运算符 |)4aIa
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ,P T5-9 m
B: EXCEPT 运算符 Q&@~<!t
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 $3BH82
C: INTERSECT 运算符 *oW^P~m/
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 hE9UWa.Q>
注:使用运算词的几个查询结果行必须是一致的。 #\{j/{VZ
12、说明:使用外连接 f\zu7,GU
A、left outer join: F.DRGi.i
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 1pDL()t
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Ln4zy*v{
B:right outer join: "A>/m"c]*
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 %"C%pA
C:full outer join: ;r1.Uz(
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 NmH:/xU?^
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二、提升 v<Ozr:lL
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |#Q4e51H
法一:select * into b from a where 1<>1 ~R$Ko(N
法二:select top 0 * into b from a pAY[XN
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) %z_L}L
insert into b(a, b, c) select d,e,f from b; RoY"Haa
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) XSv)=]{
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 jW<aAd
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Tl%n|pc
4、说明:子查询(表名1:a 表名2:b) FZi'#(y
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) UEb'b,O_9
5、说明:显示文章、提交人和最后回复时间 |nu)=Ag
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `;R
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6、说明:外连接查询(表名1:a 表名2:b) IuW5LS
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8#_"WzDw
7、说明:在线视图查询(表名1:a ) A
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select * from (SELECT a,b,c FROM a) T where t.a > 1; -:jC.}
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 8K;wX%_,
select * from table1 where time between time1 and time2 h88IP:bo
select a,b,c, from table1 where a not between 数值1 and 数值2 Y;B#_}yF
9、说明:in 的使用方法 f'-)
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select * from table1 where a [not] in ('值1','值2','值4','值6') @&4s)&-F
10、说明:两张关联表,删除主表中已经在副表中没有的信息 }vof| (Yh
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) "x"y3v'
11、说明:四表联查问题: h{BO\^6x
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 ..... _ITA $#
12、说明:日程安排提前五分钟提醒 9si,z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 mKh<M)Bz
13、说明:一条sql 语句搞定数据库分页 F VVpyB|
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 LL}b]B[
14、说明:前10条记录 M,WC+")Z=
select top 10 * form table1 where 范围 {-'S#04
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 4pw:O^v
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Rc.8j,]
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 x#0B
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(select a from tableA ) except (select a from tableB) except (select a from tableC) Q|1X|_hs
17、说明:随机取出10条数据 E{#Y=
select top 10 * from tablename order by newid() J nzI-
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18、说明:随机选择记录 1oVjx_I5y
select newid() f|cF[&wo
19、说明:删除重复记录 #ozQF~
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) L(ni6-
20、说明:列出数据库里所有的表名 Q=!f,
select name from sysobjects where type='U' 2TZ+R7B?
21、说明:列出表里的所有的 -y1t;yU.L
select name from syscolumns where id=object_id('TableName') `JrvD
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 MV,;l94?%=
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 8>(DQ"h
显示结果: OD~TWT_
type vender pcs wRLj>nc
电脑 A 1 Hrdz1:#6,
电脑 A 1 aN}l&4d
光盘 B 2 xn`<g|"#
光盘 A 2 1$^=M[v
手机 B 3 puPYM"
手机 C 3 ==W`qC4n?n
23、说明:初始化表table1 tG"lI/
TRUNCATE TABLE table1 50Kv4a"
24、说明:选择从10到15的记录 ]L?DV3N
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (!iGQj(m
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三、技巧 YJ[Jo3M@j0
1、1=1,1=2的使用,在SQL语句组合时用的较多 c~=yD:$
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0s%rd>3
如: } F; Nh7?
if @strWhere !='' 4t<l9Ilp
begin R{hq1-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 5uJ{#Zd
end s/=.a2\
else ^HM9'*&KJ
begin B<A=U r
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' iO?Sf8yJ:
end *?Pbk+}%
我们可以直接写成 TM1D|H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere $!-a)U,w$B
2、收缩数据库 _);;@T
--重建索引 n;5;D
DBCC REINDEX `=B0NC.3
DBCC INDEXDEFRAG j & x=?jX
--收缩数据和日志 ;&9A
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DBCC SHRINKDB *z{.9z`
DBCC SHRINKFILE ~LKX2Q:S
3、压缩数据库 6'^Gh B
dbcc shrinkdatabase(dbname) PM
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4、转移数据库给新用户以已存在用户权限 s,2gd'
exec sp_change_users_login 'update_one','newname','oldname' =IkG;gg
go e=<%{M&
5、检查备份集 nGdEJ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ,cqZb0VP{t
6、修复数据库 mI[$c"!BD
ALTER DATABASE [dvbbs] SET SINGLE_USER 4)4E/q/5
GO 1hT!~'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ]F]!>dKA
GO |,G=k,?_p
ALTER DATABASE [dvbbs] SET MULTI_USER
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GO 6}>:sr
7、日志清除 -1>$3-ur~
SET NOCOUNT ON 8UANB]@Y}
DECLARE @LogicalFileName sysname, s7~[7
@MaxMinutes INT, DwL4?!E
@NewSize INT ; {P"~(S%
USE tablename -- 要操作的数据库名 1 =cFV'
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 pJK}9p=4`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. |4XR [eX
@NewSize = 1 -- 你想设定的日志文件的大小(M) /h!Y/\ kI
-- Setup / initialize "V:24\vO
DECLARE @OriginalSize int <f'2dT@6
SELECT @OriginalSize = size xg>AW Q
FROM sysfiles jP-=x(
WHERE name = @LogicalFileName ji|`S\u#b
SELECT 'Original Size of ' + db_name() + ' LOG is ' + H:DTvv8e{
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + mh4`,N
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' tl:+wp7P`
FROM sysfiles ~D9VjXfL)
WHERE name = @LogicalFileName )=
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CREATE TABLE DummyTrans \AT]$`8@_
(DummyColumn char (8000) not null) fy(i<L
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DECLARE @Counter INT, nO d'$q
@StartTime DATETIME, DsY$
@TruncLog VARCHAR(255) #n[1%8l,
SELECT @StartTime = GETDATE(), Yp_R+a^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 9b0M'x'W5
DBCC SHRINKFILE (@LogicalFileName, @NewSize) M_4:~&N$
EXEC (@TruncLog) $2M dxw5
-- Wrap the log if necessary. WG_20JdJY
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired N!`8-ap\^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) \3ZQ:E}5
AND (@OriginalSize * 8 /1024) > @NewSize l5m5H,`
BEGIN -- Outer loop. MZ8jL,a^
SELECT @Counter = 0 S4jt*]w5b
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) l^F%fIRp)
BEGIN -- update ^rDT+ x
INSERT DummyTrans VALUES ('Fill Log') rX*ATN
DELETE DummyTrans M99gDN
SELECT @Counter = @Counter + 1 PKx ewd
END SseMTw:
EXEC (@TruncLog) &y}nd
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END g8_C|lVZi
SELECT 'Final Size of ' + db_name() + ' LOG is ' + E[FRx1^R9
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + f.o,VVYi
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 7sQw&yUL)
FROM sysfiles B~0L'8WzW
WHERE name = @LogicalFileName 4+V+SD
DROP TABLE DummyTrans 5nGDt~a
SET NOCOUNT OFF 8%$Vj
8、说明:更改某个表 WB=pRC@
exec sp_changeobjectowner 'tablename','dbo' Cyb-}l
9、存储更改全部表 H8ws6}C
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch C XQPbt[5
@OldOwner as NVARCHAR(128), 4@wH4H8
@NewOwner as NVARCHAR(128) f|*vWHSM
AS \xH#X=J
DECLARE @Name as NVARCHAR(128) 1D0_k
DECLARE @Owner as NVARCHAR(128) +b7}R7:AFH
DECLARE @OwnerName as NVARCHAR(128) 8"M*,?.]
DECLARE curObject CURSOR FOR K$H>/*&'~
select 'Name' = name, `FP)-^A8
'Owner' = user_name(uid) Qe!Q
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from sysobjects |vZ\tQ
where user_name(uid)=@OldOwner 7I6bZ;}d
order by name uF!3a$4]
OPEN curObject yW$ja|^E
FETCH NEXT FROM curObject INTO @Name, @Owner pX:FXzYQ
WHILE(@@FETCH_STATUS=0) fC_dSM[{c
BEGIN ;JcOm&d/hk
if @Owner=@OldOwner w2:!yQk_
begin 2o`a^'Iw
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5!55v
exec sp_changeobjectowner @OwnerName, @NewOwner \;?=h
end H(^O{JC]y!
-- select @name,@NewOwner,@OldOwner _u`NIpXSP
FETCH NEXT FROM curObject INTO @Name, @Owner r|XNS>V ,$
END <bwsK,C
close curObject ?
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deallocate curObject yn0OPjH
GO eB:OvOol*^
10、SQL SERVER中直接循环写入数据 >A$J5B>d
declare @i int EBY=ccGE{
set @i=1 !OJ@
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while @i<30 ,t+5(qi
begin S^@I4Z
insert into test (userid) values(@i) mGjxc}
set @i=@i+1 ~HwY?[}!m
end rx*1S/\PPc
小记存储过程中经常用到的本周,本月,本年函数 oRM,_
Dateadd(wk,datediff(wk,0,getdate()),-1) |5wuYG
Dateadd(wk,datediff(wk,0,getdate()),6) 1Ftl1uf
Dateadd(mm,datediff(mm,0,getdate()),0) JD^&d~n_
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) :<OInKE>Cx
Dateadd(yy,datediff(yy,0,getdate()),0) zX-6]j;
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) JM#jg-z,~
上面的SQL代码只是一个时间段 d9XX^nY.
Dateadd(wk,datediff(wk,0,getdate()),-1) sW~Z?PFP
Dateadd(wk,datediff(wk,0,getdate()),6) `eIX*R
就是表示本周时间段. :\@WY
下面的SQL的条件部分,就是查询时间段在本周范围内的: <}RU37,W
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) w#Y<~W&
而在存储过程中 )$/Gh&1G
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 2&E1) ^
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) [?<"SJ,`