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。 .!^}sp,E
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一、基础 d>YX18'<Q
1、说明:创建数据库 l.Yq4qW
CREATE DATABASE database-name vyXL F'L
2、说明:删除数据库 ;&~9k?v7L
drop database dbname Z<4Du
3、说明:备份sql server "P9SW?',
--- 创建 备份数据的 device 7W7yjG3g
USE master =kiDW6
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Frd` u.I
--- 开始 备份 l(j._j~p
BACKUP DATABASE pubs TO testBack y/\0qQ/
4、说明:创建新表 )N}.n2Y8W
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )"sJaHx<
根据已有的表创建新表: v9K=\ j
A:create table tab_new like tab_old (使用旧表创建新表) 6EY W:o
B:create table tab_new as select col1,col2... from tab_old definition only e'MLLC[
5、说明:删除新表 dZ;rn!dg>
drop table tabname R GC DC*\
6、说明:增加一个列 <)4>"SN&^
Alter table tabname add column col type ZhnRsn9
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[v-hvK
7、说明:添加主键: Alter table tabname add primary key(col) )>+J`NFa
说明:删除主键: Alter table tabname drop primary key(col) hG! |ts
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;]I~AGH:
删除索引:drop index idxname .'Rz
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注:索引是不可更改的,想更改必须删除重新建。 rpn&.#KS
9、说明:创建视图:create view viewname as select statement $-l\&V++F
删除视图:drop view viewname vIpitbFC
10、说明:几个简单的基本的sql语句 *If]f0?%
选择:select * from table1 where 范围 /vrjg)fer
插入:insert into table1(field1,field2) values(value1,value2) bQBYzvd
删除:delete from table1 where 范围 $geDB~ 2>
更新:update table1 set field1=value1 where 范围 _]q%H ve
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! r6:c<p [c
排序:select * from table1 order by field1,field2 [desc] N3SB-E+
总数:select count as totalcount from table1 <cNg_ZZ;8
求和:select sum(field1) as sumvalue from table1 ,mm9X\ '
平均:select avg(field1) as avgvalue from table1 MgG_D6tDM
最大:select max(field1) as maxvalue from table1 ^h~oxZJw
最小:select min(field1) as minvalue from table1 =Xu(Js-
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11、说明:几个高级查询运算词 }v$T1Cw
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A: UNION 运算符 <rAWu\d;
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。 +8eW/Bs@2
B: EXCEPT 运算符 <F#/wU^9
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。 3oE3bBj
C: INTERSECT 运算符 ` 8OA:4).
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。 &Rxy]kBA
注:使用运算词的几个查询结果行必须是一致的。 * u{CnH
12、说明:使用外连接 Yt#e[CYnu
A、left outer join: $bo 5:c
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 S)~Riuy$
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 XJ9l,:c,
B:right outer join: WlfS|/\%V^
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。 oMer+=vH
C:full outer join: 3GUJlFj
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。 .pd_SQ~
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二、提升 XF=GmkO
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) e Zb8x
法一:select * into b from a where 1<>1 Bvy(vc=UDW
法二:select top 0 * into b from a J^]Y`Q`
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Ow7}&\;^-
insert into b(a, b, c) select d,e,f from b; .f~x*@
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) {S;/+X,
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Ls~F4ar$/
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <+2M,fq+
4、说明:子查询(表名1:a 表名2:b) 2gC.Z:}
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) \JX.)&>
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5、说明:显示文章、提交人和最后回复时间 P0N%77p>"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) |Y42ZOK0
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Nq3q##Ut:
7、说明:在线视图查询(表名1:a ) F6xQ`T|
select * from (SELECT a,b,c FROM a) T where t.a > 1; E*_lT`Hzf
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 bWAVBF
select * from table1 where time between time1 and time2 _'lrI23I
select a,b,c, from table1 where a not between 数值1 and 数值2 ]/y&5X
9、说明:in 的使用方法 #[a+m
select * from table1 where a [not] in ('值1','值2','值4','值6') (!0=~x|Z[
10、说明:两张关联表,删除主表中已经在副表中没有的信息 (8*& 42W
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Vgh_F8G!V
11、说明:四表联查问题: M6+_Mi.
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... X)K3X:~L+
12、说明:日程安排提前五分钟提醒 I}a iy.l
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 e2v[ma-
13、说明:一条sql 语句搞定数据库分页 5$|wW}SA
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 _=.f+1W
14、说明:前10条记录 liUrw7,
select top 10 * form table1 where 范围 U_UX *
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.) b%fn1Ag9
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 27t23@{YL
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 HZ1e~IIw
(select a from tableA ) except (select a from tableB) except (select a from tableC) 4oF8F)ASj
17、说明:随机取出10条数据 ]B<Hrnn
select top 10 * from tablename order by newid() Bk~lE]Q3c7
18、说明:随机选择记录 ~8-Z=-
select newid() )bqfj>%#c
19、说明:删除重复记录 <Cvlz^K[
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) C#<:x!
20、说明:列出数据库里所有的表名 eoS8e$}
select name from sysobjects where type='U' ^+JpI*,
21、说明:列出表里的所有的 R^.oM1qu|
select name from syscolumns where id=object_id('TableName') L//Z\xr|
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 NY'sZTM&
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type l!plw,PYC
显示结果: -$E_L:M
type vender pcs !po8[fz~x
电脑 A 1 Ocq.<#||H
电脑 A 1 [lqwzW{(UN
光盘 B 2 wjF/c
光盘 A 2 IRemF@
手机 B 3 S=>54!{`x
手机 C 3 x?:[:Hf
23、说明:初始化表table1 M ]dS>W%U
TRUNCATE TABLE table1 y#:_K(A" k
24、说明:选择从10到15的记录 )QGj\2I
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc !e?GS"L~
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三、技巧 :=BFx"Y
1、1=1,1=2的使用,在SQL语句组合时用的较多 ~a:0Q{>a
"where 1=1" 是表示选择全部 "where 1=2"全部不选, hHsCr@i
如: oZxC.;xJ
if @strWhere !='' MO+g*N
begin Gpws_jw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere +_tK \MN
end P%A^TD|
else N/QTf1$
begin O(8Px
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' t@[&8j2B>
end Xm./XC
我们可以直接写成 V?Y;.n&y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Y<0;;tVf4U
2、收缩数据库 *Ppb;
--重建索引 sK8=PZ\
DBCC REINDEX x2*l5t
DBCC INDEXDEFRAG XBE+O7
--收缩数据和日志 *HFRG)[V
DBCC SHRINKDB +:3K?G-
DBCC SHRINKFILE tLXwszR0r
3、压缩数据库 JsohhkJNGi
dbcc shrinkdatabase(dbname) W 86`R
4、转移数据库给新用户以已存在用户权限 68
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exec sp_change_users_login 'update_one','newname','oldname' K' xN>qc
go "c8
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5、检查备份集
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' T8( \:v
6、修复数据库 u`I&&
ALTER DATABASE [dvbbs] SET SINGLE_USER (_h<<`@B
GO `)Z"||8K
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK n1+1/
GO 0$)uOUVJ
ALTER DATABASE [dvbbs] SET MULTI_USER U$+EUDFi3_
GO jFbj)!;
7、日志清除 S B2R
SET NOCOUNT ON 4D+S\S0bk
DECLARE @LogicalFileName sysname, 0c6b_%Rd
@MaxMinutes INT, Jg} w{,
@NewSize INT .SZ ZT0Z
USE tablename -- 要操作的数据库名 c>I(6$
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 zh8\
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. PkM]jbLe8
@NewSize = 1 -- 你想设定的日志文件的大小(M) .V~z6
-- Setup / initialize t}FwS6u
DECLARE @OriginalSize int ykAZP[^'
SELECT @OriginalSize = size ?'>pfU
FROM sysfiles 9)P-<
WHERE name = @LogicalFileName >6yA+?[:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + :g&9v_}&K{
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + MTI[Mez
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' vndD#/lXq
FROM sysfiles KHnq%#
WHERE name = @LogicalFileName bhk:Szqz
CREATE TABLE DummyTrans % YgGw:wZ
(DummyColumn char (8000) not null) Sq<ds}o'8l
DECLARE @Counter INT, )gNS%tc*K
@StartTime DATETIME, 8d|/^U.w~V
@TruncLog VARCHAR(255) Hs9; &C
SELECT @StartTime = GETDATE(), ''p7!V?
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' hYvWD.c}
DBCC SHRINKFILE (@LogicalFileName, @NewSize) LIah'6qR
EXEC (@TruncLog) Qqm$Jl!
-- Wrap the log if necessary. ^9_4#Ep(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired le7!:4/8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) FaA'%P@
AND (@OriginalSize * 8 /1024) > @NewSize d ,"L8
BEGIN -- Outer loop. tBB\^xq:
SELECT @Counter = 0 BYuoeN!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) $M:Ru@Du2
BEGIN -- update []L
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INSERT DummyTrans VALUES ('Fill Log') g$?kL
DELETE DummyTrans `4Db( ~
SELECT @Counter = @Counter + 1 pnTuYT^%)
END n0
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EXEC (@TruncLog) w *Txc}
END +.3,(l
SELECT 'Final Size of ' + db_name() + ' LOG is ' + <>l!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 7 'B9z/
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' AQ<2 "s
FROM sysfiles [TaYNc!\
WHERE name = @LogicalFileName bnZ`Wc*5b
DROP TABLE DummyTrans }L|cg2y
SET NOCOUNT OFF (~U1X4
8、说明:更改某个表 =@\Li)Y
exec sp_changeobjectowner 'tablename','dbo' P`$Y73L
9、存储更改全部表 e$Npo<u
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch yN/Uyhq
@OldOwner as NVARCHAR(128), SbYsa
@NewOwner as NVARCHAR(128) 2EAY`}Rl6.
AS [g Y.h/
DECLARE @Name as NVARCHAR(128) )4O* D92
DECLARE @Owner as NVARCHAR(128) b!l/O2
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DECLARE @OwnerName as NVARCHAR(128) ,b${3*PPQ
DECLARE curObject CURSOR FOR VT:m!<^
select 'Name' = name, y%Wbm&h
'Owner' = user_name(uid) _ry7[/)
from sysobjects U#gv ~)\k
where user_name(uid)=@OldOwner ;n2b$MB?nM
order by name ,!I'0x1OR
OPEN curObject {0J
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FETCH NEXT FROM curObject INTO @Name, @Owner y&(R1Y75
WHILE(@@FETCH_STATUS=0)
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BEGIN s9.nU
if @Owner=@OldOwner :ySQ[AJ"
begin TM*<hC
set @OwnerName = @OldOwner + '.' + rtrim(@Name) =5D@~?W ZG
exec sp_changeobjectowner @OwnerName, @NewOwner <