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。 <LN $[&f#
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一、基础 c"1d#8J
1、说明:创建数据库 p\S3A(
CREATE DATABASE database-name K67 ?
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2、说明:删除数据库 ;i>E@
drop database dbname S I5QdX
3、说明:备份sql server Bx4GFCdifC
--- 创建 备份数据的 device ]E^f8s0#V
USE master U^\~{X
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' BH a>2N
--- 开始 备份 6QQ oHYtZ
BACKUP DATABASE pubs TO testBack <vDm(-i3
4、说明:创建新表 ?%Fk0E#>2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) UULL:vqq
根据已有的表创建新表: \
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A:create table tab_new like tab_old (使用旧表创建新表) 9YhsJ~"Q
B:create table tab_new as select col1,col2... from tab_old definition only 8$Yf#;m[
5、说明:删除新表 9zd/5|W
drop table tabname 2Zip8f!
6、说明:增加一个列 Iq\oB
Alter table tabname add column col type >~~\==".
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。 mM>|fHGA
7、说明:添加主键: Alter table tabname add primary key(col) 4V8wB}y7e
说明:删除主键: Alter table tabname drop primary key(col) pr(\?\a
8、说明:创建索引:create [unique] index idxname on tabname(col....) taaAwTtk?A
删除索引:drop index idxname DU8LU*q'
注:索引是不可更改的,想更改必须删除重新建。 ':4pH#E
9、说明:创建视图:create view viewname as select statement ypo=y/!
删除视图:drop view viewname U{(07GNm#
10、说明:几个简单的基本的sql语句 aS G2K0
选择:select * from table1 where 范围 ts>}>}@vc
插入:insert into table1(field1,field2) values(value1,value2) 8ZfIh
删除:delete from table1 where 范围 ^MV%\0o
更新:update table1 set field1=value1 where 范围 =]"|x7'!
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ifZNl,
排序:select * from table1 order by field1,field2 [desc] Ypj)6d
总数:select count as totalcount from table1 ,$$$_+m\
求和:select sum(field1) as sumvalue from table1 oW6<7>1M7
平均:select avg(field1) as avgvalue from table1 \}NWR{=
最大:select max(field1) as maxvalue from table1 Dj(7'jT
最小:select min(field1) as minvalue from table1 Pc==]H(
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11、说明:几个高级查询运算词 e8<nPt`C
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A: UNION 运算符 Qe.kNdT+_
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。 ^?[<!VBI
B: EXCEPT 运算符 cLC7U?-
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。 NI:N
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C: INTERSECT 运算符 ^I?y\:.
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。 REBDr;tv
注:使用运算词的几个查询结果行必须是一致的。 1G.gPx[
12、说明:使用外连接 ?ovGYzUZ
A、left outer join: 1:UC\ WW
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。 JZxF)]^
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
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B:right outer join: LfXr(2u
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。 N\p]+[6
C:full outer join: No\&~
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。 j88sE MZ
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二、提升 B?Sfcq-
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 1R9?[RE
法一:select * into b from a where 1<>1 w{x(YVSH
法二:select top 0 * into b from a /,$\H
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) PGl-2Cr
insert into b(a, b, c) select d,e,f from b; }/3pC a
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) "m;]6B."
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 %v:h]TA
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. s/H"Ab
4、说明:子查询(表名1:a 表名2:b) 3eP0v
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) W+C_=7_
5、说明:显示文章、提交人和最后回复时间 8;&S9'ci
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Vp"Ug,1
6、说明:外连接查询(表名1:a 表名2:b) %ab)Gs
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c fO!O"D5
7、说明:在线视图查询(表名1:a ) z}2e;d 7
select * from (SELECT a,b,c FROM a) T where t.a > 1; )'`AX\
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 f<p4Pkv
select * from table1 where time between time1 and time2 <>Ddxmw
select a,b,c, from table1 where a not between 数值1 and 数值2 `h5eej&s(
9、说明:in 的使用方法 y@\Q@
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select * from table1 where a [not] in ('值1','值2','值4','值6') x`vs-Y:P
10、说明:两张关联表,删除主表中已经在副表中没有的信息 HTyF<K
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ~7WXjVZ
11、说明:四表联查问题: #ic 2ofI
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 ..... g~:(EO(w
12、说明:日程安排提前五分钟提醒 C-^%g[#
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Z1&GtM
13、说明:一条sql 语句搞定数据库分页 [Fj+p4*N
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 M8j(1&(:
14、说明:前10条记录 z T T
select top 10 * form table1 where 范围 AeCG2!8^0
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.) B00wcYM<1r
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ^|i\d\
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 0W%}z}/N
(select a from tableA ) except (select a from tableB) except (select a from tableC) VD3MJ 8!w
17、说明:随机取出10条数据 %7d@+
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select top 10 * from tablename order by newid() 3b\8907
18、说明:随机选择记录 mCNf]Yz
select newid() 33*d/%N9
19、说明:删除重复记录 aX'g9E
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ww t()
20、说明:列出数据库里所有的表名 jNG?2/P6&
select name from sysobjects where type='U' 1(7.V-(G
21、说明:列出表里的所有的 'qF3,Rw
select name from syscolumns where id=object_id('TableName') TKu68/\)
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。 BRXb<M^;_
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 D6)Cjc>a
显示结果: 'S4EKV]
type vender pcs ^~<Rz q!
电脑 A 1 RzJ}C T
电脑 A 1 p6y0W`U
光盘 B 2 &DQ4=/Z
光盘 A 2 pkN:D+gS
手机 B 3 eGe[sv"k
手机 C 3 6 #x)W
23、说明:初始化表table1 ~73i^3yf
TRUNCATE TABLE table1 <kXV1@>
24、说明:选择从10到15的记录 &Pg-|Ql
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc K&IrTA
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三、技巧 m9<%v0r
1、1=1,1=2的使用,在SQL语句组合时用的较多 #+Yp^6zg
"where 1=1" 是表示选择全部 "where 1=2"全部不选, "i{_<;p O
如: x1V2|~;p|
if @strWhere !='' !Xx<~lIC
begin hp]ng!I{\u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere +fP/|A8P
end 'W?v.W &
else JQ/t, v$G
begin [[0bhmG)
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Q^MXiEO+
end ]%<Q:+38
我们可以直接写成 &e]]F#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ce5w0&VlS
2、收缩数据库 hi3sOK*r;<
--重建索引 O? Gl4_y
DBCC REINDEX <[y$D=n
DBCC INDEXDEFRAG $]H=
--收缩数据和日志 hLytKPgt
DBCC SHRINKDB k Kp6
DBCC SHRINKFILE bxhg*A
3、压缩数据库 2^ ,H_PS
dbcc shrinkdatabase(dbname) <{NYD.
4、转移数据库给新用户以已存在用户权限 h-b5
exec sp_change_users_login 'update_one','newname','oldname' h/X5w4
go )}Rfa}MD
5、检查备份集 ,P@/=I5
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' $D/bU lFx
6、修复数据库 v :+8U[x
ALTER DATABASE [dvbbs] SET SINGLE_USER 7moElh v
GO .qIy7_^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6_%]\37_Z
GO 2l)9Lz=;L
ALTER DATABASE [dvbbs] SET MULTI_USER Z`oaaO
GO Od!F: <
7、日志清除 eN]>l
SET NOCOUNT ON )zW%\s*'
DECLARE @LogicalFileName sysname, n-hvh-ZO
@MaxMinutes INT, ]/o12pI
@NewSize INT Jny)uo8
USE tablename -- 要操作的数据库名 Q$fRi[/L
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 *TM;trfz
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ksu}+i,a
@NewSize = 1 -- 你想设定的日志文件的大小(M) '6o`^u>
-- Setup / initialize hEv=T'*,K)
DECLARE @OriginalSize int CP]S-o}yd
SELECT @OriginalSize = size k'@7ZH
FROM sysfiles b\?7?g
WHERE name = @LogicalFileName ljYpMv.>xG
SELECT 'Original Size of ' + db_name() + ' LOG is ' + aVppOxA
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + -3G 4vRIo
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 97(Xu=tX
FROM sysfiles S$jV|xKB
WHERE name = @LogicalFileName <}EV*`w4
CREATE TABLE DummyTrans tM^;?HL]
(DummyColumn char (8000) not null) *gd?>P7\0
DECLARE @Counter INT, <Qcex3
@StartTime DATETIME, )+n,5W
@TruncLog VARCHAR(255) JQ"`9RNb
SELECT @StartTime = GETDATE(), Xq,UV
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' BKC7kDK3H
DBCC SHRINKFILE (@LogicalFileName, @NewSize) <?LfOSdMs^
EXEC (@TruncLog) gV"qV
-- Wrap the log if necessary. `dv}a-Q)c
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired /ojO>Y[<
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Sa;<B:|
AND (@OriginalSize * 8 /1024) > @NewSize t;.^K\S4
BEGIN -- Outer loop. @K$VV^wp
SELECT @Counter = 0 %@lV-(5q
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Lj&1K~U
BEGIN -- update n5Nan
INSERT DummyTrans VALUES ('Fill Log') :DdBn.
DELETE DummyTrans ]6t]m2~\
SELECT @Counter = @Counter + 1 k_D4'(V:b
END 4<G?
EXEC (@TruncLog) 7Wwp )D
END ~A`&/U
SELECT 'Final Size of ' + db_name() + ' LOG is ' + HzRX$IKB3(
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ?Oy'awf_
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' E0"10Qbi
FROM sysfiles I 1 b
WHERE name = @LogicalFileName R^J.?>0
DROP TABLE DummyTrans ,4^9cFVo
SET NOCOUNT OFF Iv$:`7|crX
8、说明:更改某个表 q&XCX$N
exec sp_changeobjectowner 'tablename','dbo' M.ZEqV+k
9、存储更改全部表 jWH{;V&ZV
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch f^W[;w
@OldOwner as NVARCHAR(128), mje<d"bW
@NewOwner as NVARCHAR(128) jM5_8nS&d
AS =\~E n5
DECLARE @Name as NVARCHAR(128) r0\cc6
DECLARE @Owner as NVARCHAR(128) ?EI'^xg
DECLARE @OwnerName as NVARCHAR(128) op hH9D
DECLARE curObject CURSOR FOR q>_vE{UB
select 'Name' = name, =n@F$/h
'Owner' = user_name(uid) aO8ch
from sysobjects ]y3pE}R
where user_name(uid)=@OldOwner vkd[:CC
order by name B4]AFRI
OPEN curObject ,CJAzGBS
FETCH NEXT FROM curObject INTO @Name, @Owner 4. 1rJa
WHILE(@@FETCH_STATUS=0) [YC=d1F5
BEGIN 9$7&URwSDI
if @Owner=@OldOwner Ts|--,
begin +kjzn]}f
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 9[cp7 Rcb
exec sp_changeobjectowner @OwnerName, @NewOwner fCgBH~w,9
end eeuZUf+~]
-- select @name,@NewOwner,@OldOwner :GU,EDps
FETCH NEXT FROM curObject INTO @Name, @Owner _&8O~8tW
END &qJPwO
close curObject ;~W8v.EW
deallocate curObject Zimh_
GO J+Q+&-a
10、SQL SERVER中直接循环写入数据 P!kw;x
declare @i int lj.nCV_
set @i=1 kTnOmAw
while @i<30 >qR7'Q wP
begin vB[~pQ;Z
insert into test (userid) values(@i) <,\ `Psa)N
set @i=@i+1 W7H&R,
end P
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小记存储过程中经常用到的本周,本月,本年函数
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Dateadd(wk,datediff(wk,0,getdate()),-1) ,Pn-ZF
Dateadd(wk,datediff(wk,0,getdate()),6) (2UW_l
Dateadd(mm,datediff(mm,0,getdate()),0) 4L8z>9D
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Lp_$?MCD.
Dateadd(yy,datediff(yy,0,getdate()),0) 0y)}.'
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) o4$Ott%Wm
上面的SQL代码只是一个时间段 gfi
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Dateadd(wk,datediff(wk,0,getdate()),-1) KX!i\NHz
Dateadd(wk,datediff(wk,0,getdate()),6) 6gXIt9B.h$
就是表示本周时间段. w{pUUo:<
下面的SQL的条件部分,就是查询时间段在本周范围内的: <lUOJV{&\
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) _`H.h6h
而在存储过程中 K&*iw`
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) z9[[C^C
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Y RPm^kW