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。 xMu[#\Vc
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一、基础 Yq?FiE0
1、说明:创建数据库 VgO:`bDF
CREATE DATABASE database-name @H^Yf
2、说明:删除数据库 ?@i_\<A2
drop database dbname ]FNqNZ
3、说明:备份sql server sox0:9Oqnf
--- 创建 备份数据的 device $Dm2>:Dmt
USE master M &g1'zv?/
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 3b2[i,m<L
--- 开始 备份 lef,-{X-
BACKUP DATABASE pubs TO testBack R6A{u(
4、说明:创建新表 `i,l)X]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) * Jy'3o
根据已有的表创建新表: %cl=n!T
A:create table tab_new like tab_old (使用旧表创建新表) j%m9y_rg}
B:create table tab_new as select col1,col2... from tab_old definition only `'Af`u\R
5、说明:删除新表 )E.!jL:g
drop table tabname 0//?,'.
6、说明:增加一个列 $&Ntdn
Alter table tabname add column col type fvDt_g9 oI
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 pp#xN/V#a
7、说明:添加主键: Alter table tabname add primary key(col) ~<?+(V^D
说明:删除主键: Alter table tabname drop primary key(col) ,33[/j
8、说明:创建索引:create [unique] index idxname on tabname(col....) L:ox$RU
删除索引:drop index idxname $6evK~
注:索引是不可更改的,想更改必须删除重新建。 /uM;g9 m
9、说明:创建视图:create view viewname as select statement '*~_!lE5
删除视图:drop view viewname |KHaL?
10、说明:几个简单的基本的sql语句 `H.~#$
选择:select * from table1 where 范围 ,X05&'@Z
插入:insert into table1(field1,field2) values(value1,value2) a$*)d($
删除:delete from table1 where 范围 oXef<- :
更新:update table1 set field1=value1 where 范围 Qt@_C*,P
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! +y$%S4>0tp
排序:select * from table1 order by field1,field2 [desc] ;p!|E3o.
总数:select count as totalcount from table1 0'IV"eH2
求和:select sum(field1) as sumvalue from table1 (|EnRk-E
平均:select avg(field1) as avgvalue from table1 ]{Ytf'bG
最大:select max(field1) as maxvalue from table1 4Y)rgLFj
最小:select min(field1) as minvalue from table1 *,:>EcDr
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11、说明:几个高级查询运算词 3$u3ssOL
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A: UNION 运算符 pu:Ie#xTDf
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。 jo8hVWJ7V*
B: EXCEPT 运算符 <,r|*pkhp~
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。 LX
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C: INTERSECT 运算符 &o$z[b
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。 QxSJLi7t
注:使用运算词的几个查询结果行必须是一致的。 3++}4%w
12、说明:使用外连接 \DG
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A、left outer join: 6QwVgEnSf
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。 =q1=.VTn
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 Df\~ ZWs!
B:right outer join: v-k~Q$7~
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 PgeC\#;9
C:full outer join: -K 7jigac
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 5/vfmDt3'G
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二、提升 PJq;OM|
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) yMU>vr
法一:select * into b from a where 1<>1 A{[joo
法二:select top 0 * into b from a Z`UwXp_s
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) |\?mX=a.y
insert into b(a, b, c) select d,e,f from b; s#%$aQ|Fp
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) >tUi ;!cQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 F3-<F_4.w
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \(ygdZ{R
4、说明:子查询(表名1:a 表名2:b) S_E-H.d"
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) e7m>p\"
5、说明:显示文章、提交人和最后回复时间 oNyVRH ZH
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7,MDFO{n
6、说明:外连接查询(表名1:a 表名2:b) [g bYIwL.
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c w1aev
7、说明:在线视图查询(表名1:a ) F;4*,Ap
select * from (SELECT a,b,c FROM a) T where t.a > 1; {t.5cX"[
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 k`l={f8C
select * from table1 where time between time1 and time2 emhI1
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select a,b,c, from table1 where a not between 数值1 and 数值2 xJphG
9、说明:in 的使用方法 k$u\\`i]oC
select * from table1 where a [not] in ('值1','值2','值4','值6') {:D8@jb[
10、说明:两张关联表,删除主表中已经在副表中没有的信息 |[)k5nUQ|
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
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11、说明:四表联查问题: V`/E$a1&
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 ..... UlG8c~p
12、说明:日程安排提前五分钟提醒 C 2f=9n/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 qO;.{f
13、说明:一条sql 语句搞定数据库分页 aC\O'KcH
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 9g7d:zG
14、说明:前10条记录 f<14-R=
select top 10 * form table1 where 范围 g*]hmkYe9
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.) B3+9G,or
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [y(DtOR
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 -8HK_eQn
(select a from tableA ) except (select a from tableB) except (select a from tableC) aG"j9A~ &
17、说明:随机取出10条数据 (i1JDe
select top 10 * from tablename order by newid() N~""Lc&
18、说明:随机选择记录 rq>}]
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select newid() }ZQ)]Mr
19、说明:删除重复记录 o!]muO*Rm
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) QKW\z aG
20、说明:列出数据库里所有的表名 5r&bk`
select name from sysobjects where type='U' bW]7$?acv
21、说明:列出表里的所有的 HE;}B!>
select name from syscolumns where id=object_id('TableName') iyA=d{S;V
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。 wbIgZ]o!/;
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}~"R/iWCT
显示结果: $?_/`S13
type vender pcs s6q6)RD"
电脑 A 1 I_1(jaY
电脑 A 1 I7@|{L1|FB
光盘 B 2 Qm-I=Rh+
光盘 A 2 jW,b"[
手机 B 3 / [s TN.MG
手机 C 3 YFJw<5&
23、说明:初始化表table1 oZD+AF$R
TRUNCATE TABLE table1 VjI=5)+~
24、说明:选择从10到15的记录 4YV0v,z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc sf([8YUd
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三、技巧 Q9yIQ{>H[
1、1=1,1=2的使用,在SQL语句组合时用的较多 Ulf'gD4e
"where 1=1" 是表示选择全部 "where 1=2"全部不选, `D%U5Jb
如: 3`JLb]6
if @strWhere !='' !^yH]v
begin <y
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere wtl3Ex,DO
end =JkPE2mU
else diz=|g=w
begin 8l1s]Kqr
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 1fK]A*{p
end :*=fGwIWS
我们可以直接写成 `!udU,|N
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @A5'vf|2;.
2、收缩数据库 OH\(;RN*
--重建索引 afw`Heaa2(
DBCC REINDEX ]c9\[Kdq}H
DBCC INDEXDEFRAG x>cl$41!W
--收缩数据和日志 YE*%Y["
DBCC SHRINKDB r|_@S[hZg
DBCC SHRINKFILE AMw#_8Y
3、压缩数据库 K7 J RCLA
dbcc shrinkdatabase(dbname) "1l$]=C*
4、转移数据库给新用户以已存在用户权限 e9=UTn{!
exec sp_change_users_login 'update_one','newname','oldname' vg-Ah6BC{
go #n7F7X
5、检查备份集 zA>LrtyK(=
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 2zV{I*
6、修复数据库 =*5< w
ALTER DATABASE [dvbbs] SET SINGLE_USER `SH14A*
GO &o;d
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ? K ,d
GO ;!+-fn4C
ALTER DATABASE [dvbbs] SET MULTI_USER %lnVzGP
GO lR>p
7、日志清除 j|KjQ'9
SET NOCOUNT ON Ol
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DECLARE @LogicalFileName sysname, [ *~2Ts
@MaxMinutes INT, Q}: $F{
@NewSize INT {>3J 96
USE tablename -- 要操作的数据库名 :cxA
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 EY`]""~8v
@MaxMinutes = 10, -- Limit on time allowed to wrap log. $ {h1(ec8
@NewSize = 1 -- 你想设定的日志文件的大小(M) q^DQ9B
-- Setup / initialize S}b^_+UbP
DECLARE @OriginalSize int
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SELECT @OriginalSize = size kaT
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FROM sysfiles N>H#Ew@2U
WHERE name = @LogicalFileName (KLhF
SELECT 'Original Size of ' + db_name() + ' LOG is ' + EzeU-!|W
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :I{9k~
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ygbyia|
FROM sysfiles [[#R ry
WHERE name = @LogicalFileName B1V+CP3t
CREATE TABLE DummyTrans Eq?U$eE
(DummyColumn char (8000) not null) I/*^s
DECLARE @Counter INT, SHYbQF2
@StartTime DATETIME, LVNA`|>
@TruncLog VARCHAR(255) nWes,K6T
SELECT @StartTime = GETDATE(), iYf)FPET
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 8og8;#mnyr
DBCC SHRINKFILE (@LogicalFileName, @NewSize) q@^^jlHP
EXEC (@TruncLog) !,^y!+,Qy
-- Wrap the log if necessary. x*sDp3f[*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;:,U]@
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ?Rk[P
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AND (@OriginalSize * 8 /1024) > @NewSize M2$Hb_S{
BEGIN -- Outer loop. y9N6!M|'y
SELECT @Counter = 0 [}=a6Q>)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) v:P=t2q
BEGIN -- update }1DzWS-hh
INSERT DummyTrans VALUES ('Fill Log') /iEQ}
DELETE DummyTrans Ne)3@?
SELECT @Counter = @Counter + 1 2 :4o`o
END tVe =c
EXEC (@TruncLog) I.'/!11>
END >WA'/Sl<A<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + m1e Sn |)7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )<f4F!?,A
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' gN2oUbf8
FROM sysfiles @uz(h'~
WHERE name = @LogicalFileName 1bFGoLAEFl
DROP TABLE DummyTrans ?iZM.$![
SET NOCOUNT OFF l;rA}?,.^
8、说明:更改某个表 ^?2zoS#iw
exec sp_changeobjectowner 'tablename','dbo' !' 0PM[
9、存储更改全部表 [C/{ ru&E
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g t9(5p
@OldOwner as NVARCHAR(128), )MF 4b][
@NewOwner as NVARCHAR(128) A>8~deZ9
AS H#uN&^+H
DECLARE @Name as NVARCHAR(128) lCgzQZ
DECLARE @Owner as NVARCHAR(128) yk'L_M(=
DECLARE @OwnerName as NVARCHAR(128) N4z[=b>
DECLARE curObject CURSOR FOR Peo-t*-06
select 'Name' = name, L]%!YP\<T
'Owner' = user_name(uid) ORM3oucP
from sysobjects ~"_!O+Pj
where user_name(uid)=@OldOwner #].qjOj
order by name DK? Z
OPEN curObject 4TI`
FETCH NEXT FROM curObject INTO @Name, @Owner U)M&AYb
WHILE(@@FETCH_STATUS=0) *fs[]q'Q
BEGIN P3IBi_YyG1
if @Owner=@OldOwner 3 l}9'j
begin ~;z]
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) M~7Cb>%<
exec sp_changeobjectowner @OwnerName, @NewOwner VC0Tqk
end &Z3%UOY
-- select @name,@NewOwner,@OldOwner 8f1M6GK?
FETCH NEXT FROM curObject INTO @Name, @Owner 1KY0hAx
END 5
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close curObject 0y t36Du
deallocate curObject Ir-QD!!<
GO XdmpfUR,13
10、SQL SERVER中直接循环写入数据 P*B@it
declare @i int a~J!G:(
set @i=1 5}Id[%.x
while @i<30 ;5.<M<PH
begin jo0XF]
insert into test (userid) values(@i) LEOri=?RF
set @i=@i+1 T*gG <8
end `K:n=hpF
小记存储过程中经常用到的本周,本月,本年函数 eEfGH
Dateadd(wk,datediff(wk,0,getdate()),-1) _BY+Tfol
Dateadd(wk,datediff(wk,0,getdate()),6) 4Y}Nu
Dateadd(mm,datediff(mm,0,getdate()),0) z]SEPYq:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) *>"NUHq
Dateadd(yy,datediff(yy,0,getdate()),0) U?d
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) k6J&4?xZ
上面的SQL代码只是一个时间段 *N4/M%1P
Dateadd(wk,datediff(wk,0,getdate()),-1) UmvnVmnv
Dateadd(wk,datediff(wk,0,getdate()),6) 6K )K%a,9
就是表示本周时间段. B=;kC#Emtf
下面的SQL的条件部分,就是查询时间段在本周范围内的: Dkb`_HI
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) kYWnaY ^F
而在存储过程中 Rnoz[1y?0
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $U.|
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) t)Cf]]dV