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。 I9X\@lTf
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一、基础 x-%O1frc
1、说明:创建数据库 MBWoPK
CREATE DATABASE database-name b}!
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2、说明:删除数据库 "wcaJ;Os
drop database dbname UmR)L!QT8
3、说明:备份sql server JwG(WLb:
--- 创建 备份数据的 device 0D5Z#iW>1
USE master _Ewh:IM-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %' DOFiU
--- 开始 备份 #Vk?
BACKUP DATABASE pubs TO testBack @Jd&[T27Lr
4、说明:创建新表 )!8qJQD
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) '2lV(>"
根据已有的表创建新表: H:.~!
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A:create table tab_new like tab_old (使用旧表创建新表) iw )gNQ%z4
B:create table tab_new as select col1,col2... from tab_old definition only u?,>yf.;s
5、说明:删除新表 X!KX4H
drop table tabname a\P :jgF
6、说明:增加一个列 ,DFN:uf=l
Alter table tabname add column col type J!C \R5\
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。 UC`h o%OBF
7、说明:添加主键: Alter table tabname add primary key(col) "r^RfZ;
说明:删除主键: Alter table tabname drop primary key(col) a%%7Ew ?
8、说明:创建索引:create [unique] index idxname on tabname(col....) - Jaee,P
删除索引:drop index idxname "6U0
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注:索引是不可更改的,想更改必须删除重新建。 9\8ektq}Z
9、说明:创建视图:create view viewname as select statement V( ELrjB0
删除视图:drop view viewname `l|Oj$
10、说明:几个简单的基本的sql语句 mP)bOAU
选择:select * from table1 where 范围 A/y|pg5
插入:insert into table1(field1,field2) values(value1,value2) S{^x]h|?
删除:delete from table1 where 范围 bxE~tsM"@Y
更新:update table1 set field1=value1 where 范围 }a" =K%b<\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Xu-~j!
排序:select * from table1 order by field1,field2 [desc] aO{@.
总数:select count as totalcount from table1 7$*E0
求和:select sum(field1) as sumvalue from table1 j2G^sj"|
平均:select avg(field1) as avgvalue from table1 /\1'.GR
最大:select max(field1) as maxvalue from table1 [n"eD4 )K|
最小:select min(field1) as minvalue from table1 Xt$qjtVM
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11、说明:几个高级查询运算词 6,q0F*q
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A: UNION 运算符 gSFZ>v*6
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。 )@!fLAT
B: EXCEPT 运算符 dA<%4_WZty
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。 }83
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C: INTERSECT 运算符 4Sh8w%s
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。 ip?]&5s
注:使用运算词的几个查询结果行必须是一致的。 "`M~=RiI
12、说明:使用外连接 uH\EV`@'
A、left outer join: Ta[2uv>
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。 It3k#A0
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 YP,,vcut
B:right outer join: a;[\ nCK
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。 EjfQF C
C:full outer join: "L.k
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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。 P%R!\i
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二、提升 0MRWx%CR
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !/G}vu
法一:select * into b from a where 1<>1 P5my]4|x
法二:select top 0 * into b from a #M!u';bZ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) %oiF} >
insert into b(a, b, c) select d,e,f from b; gdIk%m4
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) 6%V:Z
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 HS|Gz3~
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. $~5H-wJ
4、说明:子查询(表名1:a 表名2:b) #?)6^uTW
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) j \rGU){
5、说明:显示文章、提交人和最后回复时间 )j2#5`?"j
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b JWHsTnB
6、说明:外连接查询(表名1:a 表名2:b) #`y[75<n
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c RQ=rB9~:ZN
7、说明:在线视图查询(表名1:a ) U*+-#
select * from (SELECT a,b,c FROM a) T where t.a > 1; syu/"KY^!
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 (rFkXK4^J
select * from table1 where time between time1 and time2 faOiNR7;h
select a,b,c, from table1 where a not between 数值1 and 数值2 4A+g-{d
9、说明:in 的使用方法 FWu:5fBZY
select * from table1 where a [not] in ('值1','值2','值4','值6') Sfe[z=7S
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"c-Ly{vEj
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) U-DQ?OtmC@
11、说明:四表联查问题: +E.
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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 ..... =cRmaD
12、说明:日程安排提前五分钟提醒 2Pb+/1*ix
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 d5-Q}D,P
13、说明:一条sql 语句搞定数据库分页 8s22VL
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 '=nmdqP
14、说明:前10条记录 igL5nE=n
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.) >V8!OaY5n
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 6W_:w
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 g@ J F
(select a from tableA ) except (select a from tableB) except (select a from tableC) Xr^ 5Th\
17、说明:随机取出10条数据 2|7:`e~h
select top 10 * from tablename order by newid() ="]lN
18、说明:随机选择记录 |8E~C~d
select newid() zwUC
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19、说明:删除重复记录 n
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ZC2aIJ
20、说明:列出数据库里所有的表名 :.=:N%3[
select name from sysobjects where type='U' 4x
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21、说明:列出表里的所有的 0Y!"3bw|
select name from syscolumns where id=object_id('TableName') (}wPu&Is,C
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。 <e#v9=}DI
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 Q@}SR%p
显示结果: z:S:[X0
type vender pcs `IlhLv
电脑 A 1 uPl7u1c
电脑 A 1 ^6# yL6E,~
光盘 B 2 R@grY:h
光盘 A 2 r1F5'?NZ(0
手机 B 3 GTOA>RB2
手机 C 3 N5)H(<}
23、说明:初始化表table1 AAfhh5i
TRUNCATE TABLE table1 wmV=GV8 d
24、说明:选择从10到15的记录 41/civX>V
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc @F 8NN\
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三、技巧 0Gj/yra9MO
1、1=1,1=2的使用,在SQL语句组合时用的较多 j&dCP@G
"where 1=1" 是表示选择全部 "where 1=2"全部不选, KT<i%)t2
如: 1/1oT
if @strWhere !='' !.%*Tp#k#
begin r;b `@
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Y->sJm
end gna!Q
else d_(;sW"I
begin 8\E=p+C
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' R6X2d\l#
end 8oUR/___
我们可以直接写成 -J!n 7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S7J.(;
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2、收缩数据库 4 dHGU^#WZ
--重建索引 EO(l?Fgw]$
DBCC REINDEX Q `K^>L1
DBCC INDEXDEFRAG -hfDf{QN
--收缩数据和日志 GR(m+%Vw!
DBCC SHRINKDB l9/}fMi
DBCC SHRINKFILE cq]0|\Vz
3、压缩数据库 Z*P/ ubV'
dbcc shrinkdatabase(dbname) !!A(A^s
4、转移数据库给新用户以已存在用户权限 iLQO
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exec sp_change_users_login 'update_one','newname','oldname' 2@T0QJ
go n[y=DdiKGS
5、检查备份集 ?lqqu#;8
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Q,9KLi3
6、修复数据库 D*46,>Tv
ALTER DATABASE [dvbbs] SET SINGLE_USER ~{g/
GO m.6uLaD"!}
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Ib2&L
GO Dd0yQgCu
ALTER DATABASE [dvbbs] SET MULTI_USER ^{J^oZ'%~
GO i:N-Q)<Q*)
7、日志清除 !p ~.Y+
SET NOCOUNT ON o9ys$vXt*
DECLARE @LogicalFileName sysname, #2\M(5d
@MaxMinutes INT, -mO<(wfV>
@NewSize INT
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USE tablename -- 要操作的数据库名 n9
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 !<h9XccN
@MaxMinutes = 10, -- Limit on time allowed to wrap log. f dJg7r*
@NewSize = 1 -- 你想设定的日志文件的大小(M) LDw.2E
-- Setup / initialize -A}$5/
DECLARE @OriginalSize int O>f*D+A-
SELECT @OriginalSize = size rv)Eg53Q
FROM sysfiles r_ m|?U
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WHERE name = @LogicalFileName rx]Q,;"
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ku57<kb
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 6qV1_M#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' )jwovS?V
FROM sysfiles s%#u)nw19
WHERE name = @LogicalFileName ;=%cA#}_0
CREATE TABLE DummyTrans ~D/Lo$K"
(DummyColumn char (8000) not null) IY~I=}
DECLARE @Counter INT, 4`5W] J]6
@StartTime DATETIME, uFuH/(}K[
@TruncLog VARCHAR(255) i+Ne.h
SELECT @StartTime = GETDATE(), W7s
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <b4}
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) _;x` 6LM
EXEC (@TruncLog) f[`&3+
-- Wrap the log if necessary. ~6u|@pnI
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired cWQ &zc
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) O d6'bO;G
AND (@OriginalSize * 8 /1024) > @NewSize taVK&ohWx
BEGIN -- Outer loop. U/HF6=Wot
SELECT @Counter = 0 jA@
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) $rjm MSxi
BEGIN -- update &H,UWtU+
INSERT DummyTrans VALUES ('Fill Log') g
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DELETE DummyTrans PHez5 }T
SELECT @Counter = @Counter + 1 &a >UVs?=
END yWN'va1+$
EXEC (@TruncLog) p&xj7qwp@F
END "FE%k>aV@v
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~y 2joStx
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 0aGauG[
FROM sysfiles N1>M<N03
WHERE name = @LogicalFileName ok-q9dM
DROP TABLE DummyTrans J| 46i
SET NOCOUNT OFF DDT]A<WUV
8、说明:更改某个表 lS2`#l >
exec sp_changeobjectowner 'tablename','dbo' }
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9、存储更改全部表 I_Gm2Dd
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch q|lP?-j
@OldOwner as NVARCHAR(128), !t)uRJ
@NewOwner as NVARCHAR(128) ls "Z4v(L6
AS sV%=z}n=
DECLARE @Name as NVARCHAR(128) frQ=BV5%6
DECLARE @Owner as NVARCHAR(128) oY\;KPz
DECLARE @OwnerName as NVARCHAR(128) 't\sXN+1
DECLARE curObject CURSOR FOR pP\^bjI
select 'Name' = name, :-2sKD y
'Owner' = user_name(uid) uW(Ngcpr
from sysobjects L]X Lv9J0
where user_name(uid)=@OldOwner ][\ uH|
order by name {j[*:l0Ui
OPEN curObject C-Y7n5
FETCH NEXT FROM curObject INTO @Name, @Owner z`J-J*R>d
WHILE(@@FETCH_STATUS=0) g]b%<DJ
BEGIN za.^vwkBk2
if @Owner=@OldOwner ARJtE@s6Y
begin +,ld;NM{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2C_I3S~U
exec sp_changeobjectowner @OwnerName, @NewOwner 527u d^:
end *MWI`=c
-- select @name,@NewOwner,@OldOwner {Z$]Rj
FETCH NEXT FROM curObject INTO @Name, @Owner 1JGww]JZo
END FGo)]U
close curObject Me+)2S 9
deallocate curObject /PBK:B
GO o}D7 $6
10、SQL SERVER中直接循环写入数据 MA 6uJT
declare @i int *z'Rl'j9[
set @i=1 hz2f7g
while @i<30 #\}xyPS
begin p2GN93,u@P
insert into test (userid) values(@i) +b dnTV6
set @i=@i+1 #KL W&A
end Pj^Ccd'>=
小记存储过程中经常用到的本周,本月,本年函数 >u`Ci>tY
Dateadd(wk,datediff(wk,0,getdate()),-1) _=qk.| p/
Dateadd(wk,datediff(wk,0,getdate()),6) nzB!0U
Dateadd(mm,datediff(mm,0,getdate()),0) {X\FS
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ZI!;~q
Dateadd(yy,datediff(yy,0,getdate()),0) _2})URU<S
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ka8=`cn
上面的SQL代码只是一个时间段 2Aq+:ud)P
Dateadd(wk,datediff(wk,0,getdate()),-1) !uKuO
Dateadd(wk,datediff(wk,0,getdate()),6) z)&&Ym#
就是表示本周时间段. 0NSCeq%;6q
下面的SQL的条件部分,就是查询时间段在本周范围内的: Je#3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) lb)i0`AN+
而在存储过程中 ',Oc+jLR
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %A@U7gqc
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) %8"Aq