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。 S$$SLy:P
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一、基础 2PRiiL@
1、说明:创建数据库 '7oCWHq[
CREATE DATABASE database-name ITqAy1m@C
2、说明:删除数据库 GK1nGdT]
drop database dbname Y*\h?p[,
3、说明:备份sql server vazA@|^8
--- 创建 备份数据的 device NQZ /E )f
USE master Ert={"Q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' !uIY ,
--- 开始 备份 vWM&4|Q1~
BACKUP DATABASE pubs TO testBack 0,0Z!-Y
4、说明:创建新表 'Q :%s
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) jN*wbqL
根据已有的表创建新表: z[<Na3]
A:create table tab_new like tab_old (使用旧表创建新表) Bt,'g*Cs
B:create table tab_new as select col1,col2... from tab_old definition only s5mJ
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5、说明:删除新表
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drop table tabname *c/V('D/
6、说明:增加一个列 M/9[P*
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Alter table tabname add column col type \<T7EV.
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。 N wNxO
7、说明:添加主键: Alter table tabname add primary key(col) 'kC#GTZi
说明:删除主键: Alter table tabname drop primary key(col) #\^=3A|b
8、说明:创建索引:create [unique] index idxname on tabname(col....) rCczQ71W
删除索引:drop index idxname ,VEE<*'X
注:索引是不可更改的,想更改必须删除重新建。 ZX`x9/0&
9、说明:创建视图:create view viewname as select statement `5wiXsNjLY
删除视图:drop view viewname w6X:39d
10、说明:几个简单的基本的sql语句 4^:dmeMZ`
选择:select * from table1 where 范围 -.MJ3
插入:insert into table1(field1,field2) values(value1,value2) oi,KA
删除:delete from table1 where 范围 1hi,&h
更新:update table1 set field1=value1 where 范围 /}6y\3h
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! wL3RcXW``e
排序:select * from table1 order by field1,field2 [desc] V?"U)Y@Y
总数:select count as totalcount from table1 f"*4R
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求和:select sum(field1) as sumvalue from table1 =P9rOK=
平均:select avg(field1) as avgvalue from table1 k\T]*A
最大:select max(field1) as maxvalue from table1 U>.5vK.+
最小:select min(field1) as minvalue from table1 >]gB@tn[
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11、说明:几个高级查询运算词 *aWh]x9TlU
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A: UNION 运算符 >yn]h4M
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。 lt:&lIW,3
B: EXCEPT 运算符 N}7b^0k
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。 0n`Temb/
C: INTERSECT 运算符 sH2xkUp
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。 Hf_
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注:使用运算词的几个查询结果行必须是一致的。 sn^ 3xAF
12、说明:使用外连接 .|07IH/Di{
A、left outer join: VWK/(>TP
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。 CL7/J[TS
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 ;y@zvec4
B:right outer join: kJO Z;X=9/
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。 m,q)lbRl
C:full outer join: N5=}0s]e
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。 ^mFsrw
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二、提升 iM:-750n/
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) G:lhrT{
法一:select * into b from a where 1<>1 ps,Kj3^T<
法二:select top 0 * into b from a zZRLFfz<9
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) tB`"gC~
insert into b(a, b, c) select d,e,f from b; f-[.^/
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) Ps\4k#aOv
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 R_GA`U\ {
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. -X%twy=
4、说明:子查询(表名1:a 表名2:b) N2[j By8M
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) bDh4p]lm
5、说明:显示文章、提交人和最后回复时间 C Q iHk
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b UukY9n];]
6、说明:外连接查询(表名1:a 表名2:b) noa+h<vGb
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c r1RM7y
7、说明:在线视图查询(表名1:a ) 2h*aWBLk
select * from (SELECT a,b,c FROM a) T where t.a > 1; )T
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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 7p':a)
select * from table1 where time between time1 and time2 . a @7
select a,b,c, from table1 where a not between 数值1 and 数值2 mSu$1m8
9、说明:in 的使用方法 *& );-r`.
select * from table1 where a [not] in ('值1','值2','值4','值6') Sw-2vnSdM
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Z>Rshtg
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <6+B;brh
11、说明:四表联查问题: *9=}f;~
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... CW8YNJ'
12、说明:日程安排提前五分钟提醒 AU%Yr6
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 p=x&X~
13、说明:一条sql 语句搞定数据库分页 !J<0.nO/:
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 4[;}/-
14、说明:前10条记录 b 1Wz
select top 10 * form table1 where 范围 []
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) _1$ Y\Y
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) d`$w3Hy
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 +cmi?~KS*
(select a from tableA ) except (select a from tableB) except (select a from tableC) <GQ=PrT|/
17、说明:随机取出10条数据 gjnEN1T22
select top 10 * from tablename order by newid() 'IIa,']H
18、说明:随机选择记录 D5bi)@G7z
select newid() OT|0_d?bD
19、说明:删除重复记录 oSy9Xw
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Q$`uZ
20、说明:列出数据库里所有的表名 4%_c9nat
select name from sysobjects where type='U' MzKl=G
21、说明:列出表里的所有的 4A(h'(^7A
select name from syscolumns where id=object_id('TableName') Tw`dLK?
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。 &LB`
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 Ic!x y
显示结果: 2Y[n
type vender pcs Y*#TfWv:
电脑 A 1 ls9Y?
电脑 A 1 y<R5}F
光盘 B 2 Da6l=M
光盘 A 2 |)%H_TXTy
手机 B 3 46 \!W(O~y
手机 C 3 W)
23、说明:初始化表table1 #{?RE?nD
TRUNCATE TABLE table1 FS @55mQ
24、说明:选择从10到15的记录 @t$yg$Q?[
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc gPd,
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三、技巧 ?/sn"~"
1、1=1,1=2的使用,在SQL语句组合时用的较多 >zfx2wh\a
"where 1=1" 是表示选择全部 "where 1=2"全部不选, A8S9HXL
如: HP<a'| r
if @strWhere !='' KXcRm)
begin f qWme:x
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere mO TA
end &P35\q
else yn(bW\
begin /6y{?0S
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +N2ILE8[<
end g@/}SJh/>
我们可以直接写成 TEj"G7]1$A
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere -*T0Cl.
2、收缩数据库 KZ AF9
--重建索引 ta x:9j|~
DBCC REINDEX Lrr(7cH,
DBCC INDEXDEFRAG pg_H' 0R
--收缩数据和日志 ^AOJ^@H^>
DBCC SHRINKDB B^R44j]3"
DBCC SHRINKFILE ,v=pp;
3、压缩数据库 QpoC-4F
dbcc shrinkdatabase(dbname) x6Gl|e[jv
4、转移数据库给新用户以已存在用户权限 Tl]yl$
exec sp_change_users_login 'update_one','newname','oldname' w6Mv%ZO_
go TMsCl6dB
5、检查备份集 tBl(E
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^x^(Rk}|
6、修复数据库 |_+l D|'
ALTER DATABASE [dvbbs] SET SINGLE_USER :1gpbfW
GO #a
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK )_o^d>$da
GO 4N7|LxNNl_
ALTER DATABASE [dvbbs] SET MULTI_USER akCCpnX_d
GO z" ?WT$
7、日志清除 ]EQ*!
SET NOCOUNT ON o:4#AkS
DECLARE @LogicalFileName sysname, _E6N*ORV
@MaxMinutes INT, zq ?xY`E
@NewSize INT U^)`_\/;?
USE tablename -- 要操作的数据库名 10m|?
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2 1+[9
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Q~' \oWz
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2!b##`UjA7
-- Setup / initialize `Nz`5}8.?
DECLARE @OriginalSize int .XkVdaX
SELECT @OriginalSize = size `P:[.hRu
FROM sysfiles H<?s[MH[
WHERE name = @LogicalFileName -2 8bJ,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "d}ey=$h4
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Co=Bq{GY
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' u'DpZ
FROM sysfiles 8=0I4\
WHERE name = @LogicalFileName $2}%3{<j
CREATE TABLE DummyTrans EUV8H}d5
(DummyColumn char (8000) not null) &=:3/;c
DECLARE @Counter INT, ZYt <O
@StartTime DATETIME, gMPp'^g]_
@TruncLog VARCHAR(255) YZtd IG
SELECT @StartTime = GETDATE(), M&Ln'BC
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' H ="I=}
DBCC SHRINKFILE (@LogicalFileName, @NewSize) in K;n
EXEC (@TruncLog) tAY{+N]f
-- Wrap the log if necessary. .EH1;/
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired I6@"y0I
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) |~18MW
AND (@OriginalSize * 8 /1024) > @NewSize AUIp
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BEGIN -- Outer loop. WNKP';(a@G
SELECT @Counter = 0 8`]yp7ueS
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) DpT$19Q+
BEGIN -- update i*!2n1c[
INSERT DummyTrans VALUES ('Fill Log') ga S}>?qk
DELETE DummyTrans \W=
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SELECT @Counter = @Counter + 1
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END V s=o@
EXEC (@TruncLog) ?Drq!?3PDc
END Ve)BF1YG
SELECT 'Final Size of ' + db_name() + ' LOG is ' + z%lJWvaA7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2\T\p<_20
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ` QW=<Le?
FROM sysfiles 5nsoWqnE8
WHERE name = @LogicalFileName >&7^yXS
DROP TABLE DummyTrans ?`O^;f
SET NOCOUNT OFF S QGYH
8、说明:更改某个表 Un
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exec sp_changeobjectowner 'tablename','dbo' r=54@`O!
9、存储更改全部表 SR?(z
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %&V%=-O_7
@OldOwner as NVARCHAR(128), S)4p'cUwq
@NewOwner as NVARCHAR(128) %*Uc,V
AS hv\Dz*XTs0
DECLARE @Name as NVARCHAR(128) Y|
ch ;
DECLARE @Owner as NVARCHAR(128) <l5m\A
DECLARE @OwnerName as NVARCHAR(128) Cz9MXb]B
DECLARE curObject CURSOR FOR 3hUP>F8
select 'Name' = name, VRD^> Gi
'Owner' = user_name(uid) DGS,iRLnA
from sysobjects qE]e+S?57a
where user_name(uid)=@OldOwner $z 5kA9
order by name ;_E|I=%'E
OPEN curObject %:;g|PC
FETCH NEXT FROM curObject INTO @Name, @Owner P*VZ$bUe5@
WHILE(@@FETCH_STATUS=0) zZ<*
BEGIN
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if @Owner=@OldOwner }@tgc?CD
begin jh`[Y7RJO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) rzLW@k
exec sp_changeobjectowner @OwnerName, @NewOwner zEukEA^9`
end {s*2d P)
-- select @name,@NewOwner,@OldOwner !=a]Awr\
FETCH NEXT FROM curObject INTO @Name, @Owner \^RKb-6n
END UF*R1{
close curObject P~iZae
deallocate curObject jiLJiYMg
GO "dvo@n|
10、SQL SERVER中直接循环写入数据 hCd? Kti
declare @i int eR6vO5to
set @i=1 <yBa5m@/
while @i<30 j:/Z_v'
begin g%!U7CM6h
insert into test (userid) values(@i) fBv:
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set @i=@i+1 [K'gvLt1
end /!MKijI
小记存储过程中经常用到的本周,本月,本年函数 &;L=f;
Dateadd(wk,datediff(wk,0,getdate()),-1) ^w<aS
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Dateadd(wk,datediff(wk,0,getdate()),6) L/]
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Dateadd(mm,datediff(mm,0,getdate()),0) X ,^([$
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Pt/]Z<VL
Dateadd(yy,datediff(yy,0,getdate()),0) 0(:SEiz6s
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) zR]!g|;f
上面的SQL代码只是一个时间段 aW{5m@p{"
Dateadd(wk,datediff(wk,0,getdate()),-1) x-%RRm<V
Dateadd(wk,datediff(wk,0,getdate()),6) ftl?x'P%
就是表示本周时间段. yO!M$aOn/
下面的SQL的条件部分,就是查询时间段在本周范围内的: ]t`SCsoo
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) .5}Gt>4XM
而在存储过程中 57gt"f
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 4K?
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) JPng !tvR