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。 2x5^kN7
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一、基础 v*";A
1、说明:创建数据库 "_^vQ1M]Z
CREATE DATABASE database-name LUs)"ZAi|
2、说明:删除数据库 *O|_)G
drop database dbname ObPXVqG"?
3、说明:备份sql server 'kOkwGf!
--- 创建 备份数据的 device !n7'TM'
USE master oyT`AYa
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;A6%YY
--- 开始 备份 H@xHkqan
BACKUP DATABASE pubs TO testBack n!dXjInV
4、说明:创建新表 5,\-;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) gc\/A\F<
根据已有的表创建新表: O llS
A:create table tab_new like tab_old (使用旧表创建新表) kzk8b?rOA
B:create table tab_new as select col1,col2... from tab_old definition only C 547})
5、说明:删除新表 W:maE9E=
drop table tabname g#k@R'7E
6、说明:增加一个列 `# U<'$
Alter table tabname add column col type u`CHM:<<?
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。 `w&?SXFO8
7、说明:添加主键: Alter table tabname add primary key(col) 7@&mGUALO
说明:删除主键: Alter table tabname drop primary key(col) 0GlQWRa
8、说明:创建索引:create [unique] index idxname on tabname(col....) /a*8z,x
删除索引:drop index idxname c/7}5#Rs
注:索引是不可更改的,想更改必须删除重新建。 )K8^}L,
9、说明:创建视图:create view viewname as select statement ;hPVe_/
删除视图:drop view viewname :7M%/#Fy
10、说明:几个简单的基本的sql语句 -%Rw2@vU
选择:select * from table1 where 范围 H_ a##z
插入:insert into table1(field1,field2) values(value1,value2) ~:L5Ar<
删除:delete from table1 where 范围 TMGYNb%<bX
更新:update table1 set field1=value1 where 范围 .i {yW
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6j8\3H~
排序:select * from table1 order by field1,field2 [desc] 6oa>\PDy
总数:select count as totalcount from table1 \QQWh wE
求和:select sum(field1) as sumvalue from table1 M]|]b-#
平均:select avg(field1) as avgvalue from table1 7'OR;b$
最大:select max(field1) as maxvalue from table1 a@Vk(3Rx_
最小:select min(field1) as minvalue from table1 Wks zNh
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11、说明:几个高级查询运算词 T
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A: UNION 运算符 KWxTN|>
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。 q44vI
B: EXCEPT 运算符 ]c v/dY#
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。 cNT !}8h^
C: INTERSECT 运算符 W\($LD"X
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。 rizjH+
注:使用运算词的几个查询结果行必须是一致的。 C=CZtjUt
12、说明:使用外连接 $}IG+,L
A、left outer join: amq,^
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 .Tm.M7
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c fN@ZJ~F%j
B:right outer join: 3-E-\5I
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 & kVa*O
C:full outer join: Tay$::V
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。
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二、提升 *P5\T4!+d
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) t*; KxQ+'?
法一:select * into b from a where 1<>1 daP_Kz/2K
法二:select top 0 * into b from a pacD7'1{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 4s~X
insert into b(a, b, c) select d,e,f from b; BeLqk3'/
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) $UdBZT-
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ~ o2Z5,H
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {]U
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4、说明:子查询(表名1:a 表名2:b) 5~Ek_B
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) WO{7/h</
5、说明:显示文章、提交人和最后回复时间 p;'.7_1
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `&.qHw)
6、说明:外连接查询(表名1:a 表名2:b)
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c `1n^~
7、说明:在线视图查询(表名1:a ) 5!S#}=f=
select * from (SELECT a,b,c FROM a) T where t.a > 1; ,;5%&T
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ,\X! :y~
select * from table1 where time between time1 and time2 eub}+~_?[
select a,b,c, from table1 where a not between 数值1 and 数值2 { `Z~T&}~T
9、说明:in 的使用方法 Nd"IW${Kg
select * from table1 where a [not] in ('值1','值2','值4','值6') b{,v?7^4
10、说明:两张关联表,删除主表中已经在副表中没有的信息 v&(=^A\eN
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) \.oJ/++
11、说明:四表联查问题: ]cv|dc=
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 ..... 7]{t^*
12、说明:日程安排提前五分钟提醒 Q\}-MiI/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 1<Mb@t
13、说明:一条sql 语句搞定数据库分页 UCjx
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 rM,f7hm[S*
14、说明:前10条记录 PYWFz
select top 10 * form table1 where 范围 2}XRqa.|
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.) 1ig*Xp[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) &4 KUXn[F
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 d/F^ez
(select a from tableA ) except (select a from tableB) except (select a from tableC) y\uBVa<B
17、说明:随机取出10条数据 <9
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select top 10 * from tablename order by newid() )`{m |\b
18、说明:随机选择记录 ubfh4
select newid() _b/zBFa%
19、说明:删除重复记录 yQ[ ;.<%v
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) OI6Mx$
20、说明:列出数据库里所有的表名 eR>8V8@
select name from sysobjects where type='U' MZX)znO
21、说明:列出表里的所有的 ZiQ<SSo:
select name from syscolumns where id=object_id('TableName') oy#(]K3`O
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。 )-1e}VF(U
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 h%$^s0w
显示结果: QwpX3
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type vender pcs z9OpMA
电脑 A 1 -6I*k |%8T
电脑 A 1 1U.X[}e
光盘 B 2 LTzdg >\oJ
光盘 A 2 2]9
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手机 B 3 g.di3GGi
手机 C 3 6'N_bNW
23、说明:初始化表table1 Ns1n|^9
TRUNCATE TABLE table1 'R'hRMD9o
24、说明:选择从10到15的记录 ;SjNZi)4d
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc P2f^]z
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三、技巧 y;fF|t<y
1、1=1,1=2的使用,在SQL语句组合时用的较多 L5zCL0j`
"where 1=1" 是表示选择全部 "where 1=2"全部不选, gl`J(
如: o938!jML_
if @strWhere !='' W/,:-R&'>
begin (!5Pl`:j"
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere sT!?nn3O`
end <yEApWd;
else @{fwM;me]P
begin 4.wrY6+V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' BI-'&kPk
end L>1y[
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我们可以直接写成 WvJ:yUb2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;>6~}lMgJ
2、收缩数据库 }PBL
--重建索引 L-}Uj^yF
DBCC REINDEX p.8
DBCC INDEXDEFRAG ohx$;j
--收缩数据和日志 O/Hj-u6&A
DBCC SHRINKDB 2bw), W
DBCC SHRINKFILE Hc>yZ:c;
3、压缩数据库 'a JE+
dbcc shrinkdatabase(dbname) fa/o4S<
4、转移数据库给新用户以已存在用户权限 x"C7NW[$
exec sp_change_users_login 'update_one','newname','oldname' .),9qz`
go /*BU5
5、检查备份集 D]"W|.6@
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' AhA&=l
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6、修复数据库 ]R}(CaT1
ALTER DATABASE [dvbbs] SET SINGLE_USER V3cKdlu Na
GO qyVARy
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6QT&{|q=
GO p9 ,[kb
ALTER DATABASE [dvbbs] SET MULTI_USER J%r:"Jm[y1
GO sm{0o$\Z
7、日志清除 ^W@8KB
SET NOCOUNT ON yevJA?C4 v
DECLARE @LogicalFileName sysname, WFk%nO/
@MaxMinutes INT, %vZHHBylu
@NewSize INT k\SqDmv
USE tablename -- 要操作的数据库名 BGj!/E
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 +UX~'t_'v
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1fIx@
@NewSize = 1 -- 你想设定的日志文件的大小(M) J;wBS w%1
-- Setup / initialize F|m &n&
DECLARE @OriginalSize int _e>N3fT
SELECT @OriginalSize = size S~fP$L5
FROM sysfiles D{\o*\TN
WHERE name = @LogicalFileName 0n2H7}Uq
SELECT 'Original Size of ' + db_name() + ' LOG is ' + U" 3L
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ' ,]Aj!q
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ,66(*\xT
FROM sysfiles
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WHERE name = @LogicalFileName oO3^9?Z
CREATE TABLE DummyTrans c*zeO@AAn
(DummyColumn char (8000) not null) 2TB'HNTFx
DECLARE @Counter INT, kjsj~jwvv
@StartTime DATETIME, ( Ly^+Hjg
@TruncLog VARCHAR(255) TTa3DbFp%
SELECT @StartTime = GETDATE(), eE
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' v_U/0
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) gk?H@b*
EXEC (@TruncLog) \zk>cQ
-- Wrap the log if necessary. 8mdVh\i!Kf
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8|\ -(:v
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) V6c8o2G;+
AND (@OriginalSize * 8 /1024) > @NewSize : 4-pnn
BEGIN -- Outer loop. r|u R!=*|?
SELECT @Counter = 0 [hot,\+f
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) >)*d/ ^
BEGIN -- update 3w p@OF_
INSERT DummyTrans VALUES ('Fill Log') *Od?>z
DELETE DummyTrans gn.)_
SELECT @Counter = @Counter + 1 wxJ"{(;
END 'CJ_&HR
EXEC (@TruncLog) SQU@JKi;g
END $\]Mvd
SELECT 'Final Size of ' + db_name() + ' LOG is ' + )Kl@dj
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nwfu@h0G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' bYem0hzOe
FROM sysfiles !@P{s'<:
WHERE name = @LogicalFileName d^tY?*n
DROP TABLE DummyTrans vNdX
SET NOCOUNT OFF ~~"U[G1
8、说明:更改某个表 $K\e
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exec sp_changeobjectowner 'tablename','dbo' M
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9、存储更改全部表 3 @O/#CP+
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch jJvd!,=)
@OldOwner as NVARCHAR(128), !
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@NewOwner as NVARCHAR(128) e~># M$
AS T\4>4eX-
DECLARE @Name as NVARCHAR(128) ~^'t70 :D
DECLARE @Owner as NVARCHAR(128) "mU2^4q
DECLARE @OwnerName as NVARCHAR(128) ,SdxIhL
DECLARE curObject CURSOR FOR g co;8e_
select 'Name' = name, In:V.'D/>t
'Owner' = user_name(uid) s{X+0_@Q
from sysobjects Wq 1OYZ,
where user_name(uid)=@OldOwner 5oB#{h
order by name m@D :t5
OPEN curObject fh1-]$z`~
FETCH NEXT FROM curObject INTO @Name, @Owner MZX@Gi<S[
WHILE(@@FETCH_STATUS=0) y9@j-m&
BEGIN <pG 4g
if @Owner=@OldOwner }9z$72;Qdq
begin Q=[ IO,f
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @'hkU$N)
exec sp_changeobjectowner @OwnerName, @NewOwner =mcQe^M
end +m~3InWq
-- select @name,@NewOwner,@OldOwner u!It';j
FETCH NEXT FROM curObject INTO @Name, @Owner 4pcIH5)z
END YReI|{O$c
close curObject \>j@!W
deallocate curObject j2:9ahW
GO CSWA/#&8>
10、SQL SERVER中直接循环写入数据 tdu:imH~
declare @i int ^
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set @i=1 *U8,Q]gS
while @i<30 37tJ6R6[
begin @l_rB~
insert into test (userid) values(@i) J=O_nup6C
set @i=@i+1 nS.qK/.s
end DI-CC[
小记存储过程中经常用到的本周,本月,本年函数 6Rg>h
Dateadd(wk,datediff(wk,0,getdate()),-1) Lke!VS!P&
Dateadd(wk,datediff(wk,0,getdate()),6) \qG` ts
Dateadd(mm,datediff(mm,0,getdate()),0) z<yqQ[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) zY4y]k8D*
Dateadd(yy,datediff(yy,0,getdate()),0) 7}&vEc@w&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) iM8l,Os]<f
上面的SQL代码只是一个时间段 dd6l+z
Dateadd(wk,datediff(wk,0,getdate()),-1) =gd~rk9
Dateadd(wk,datediff(wk,0,getdate()),6) ,K&L/*
就是表示本周时间段. ?4W6TSW-'
下面的SQL的条件部分,就是查询时间段在本周范围内的: a`C2:Z23(#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) YXU2UIY<~
而在存储过程中 bQ0+Y?,+/
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 9r8bSV3`
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) CX5>/