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。 -Mx\W|YK
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一、基础 oTLA&dy@
1、说明:创建数据库 .m/$ku{/J
CREATE DATABASE database-name `j)S7KN
2、说明:删除数据库 L$rMfeS
drop database dbname ]R?{9H|jwE
3、说明:备份sql server glo Y@k~
--- 创建 备份数据的 device bjCO@t
USE master >A_:qyGk
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' TVs#,
--- 开始 备份 3I):W9$Qp
BACKUP DATABASE pubs TO testBack eF=cMC
4、说明:创建新表 IVdM}"+
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 9hn+eU
根据已有的表创建新表: ExKjH*gn
A:create table tab_new like tab_old (使用旧表创建新表) DITo.PU
B:create table tab_new as select col1,col2... from tab_old definition only HmQ.'
5、说明:删除新表 Y5,[udF:O
drop table tabname &Ay[mZQ 7
6、说明:增加一个列 NcMohpkq
Alter table tabname add column col type vj,OX~|
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 43m@4Yb
7、说明:添加主键: Alter table tabname add primary key(col) /|MHZ$Y9w?
说明:删除主键: Alter table tabname drop primary key(col) LfsqtQ=J`
8、说明:创建索引:create [unique] index idxname on tabname(col....) mtd ,m
删除索引:drop index idxname =R6IW,*
注:索引是不可更改的,想更改必须删除重新建。 IMcuoQ5
9、说明:创建视图:create view viewname as select statement
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删除视图:drop view viewname 56`Tna,t
10、说明:几个简单的基本的sql语句 1~aP)q
选择:select * from table1 where 范围 o4PJ9x5R!
插入:insert into table1(field1,field2) values(value1,value2) ~4^~w#R
删除:delete from table1 where 范围 =&~7Q"
更新:update table1 set field1=value1 where 范围 9S_PZH
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! U_[<,JE
排序:select * from table1 order by field1,field2 [desc] l2Pry'3
总数:select count as totalcount from table1 aP&bW))CI
求和:select sum(field1) as sumvalue from table1 e !2SO*O
平均:select avg(field1) as avgvalue from table1 orON)Sks
最大:select max(field1) as maxvalue from table1 c0aXOG^
最小:select min(field1) as minvalue from table1 u/_TR;u=q
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11、说明:几个高级查询运算词 O3K TKL]
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A: UNION 运算符 ` G-V
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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。 $s]vZ(H
B: EXCEPT 运算符 ZULnS*V;5
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 iO@UzD#v
C: INTERSECT 运算符 ic;M=dsh:
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 OC=g 1
注:使用运算词的几个查询结果行必须是一致的。 zN3b`K. i
12、说明:使用外连接 X%rsa7H3J
A、left outer join: euiP<[|h=
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 !fmbm4!a
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c r?2EJE2{V
B:right outer join: ,[UK32KWI
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 D8 BmC
C:full outer join: {3`cSm6c
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 RIdh],-
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二、提升 pt$\pQ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) nr]:Y3KyxX
法一:select * into b from a where 1<>1 sOqT*gwr:
法二:select top 0 * into b from a (|9t+KP
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) G$mAyK:
insert into b(a, b, c) select d,e,f from b; 9_-6Lwj6t
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 5_7y 1
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Aw$+Ew[8 2
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ~J:]cy)Q
4、说明:子查询(表名1:a 表名2:b) iu.v8I;<
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) B?
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5、说明:显示文章、提交人和最后回复时间 w<&R|= 93
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b K;Fs5|gFU
6、说明:外连接查询(表名1:a 表名2:b) lW|`8ykp
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c W+Q^u7K
7、说明:在线视图查询(表名1:a ) z3Zo64V~7
select * from (SELECT a,b,c FROM a) T where t.a > 1; Q].p/-[(
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 (Cb;=:3G
select * from table1 where time between time1 and time2 of=N+
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select a,b,c, from table1 where a not between 数值1 and 数值2 V|&->9"
9、说明:in 的使用方法 Ji)Ys
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select * from table1 where a [not] in ('值1','值2','值4','值6') c> 0R_
10、说明:两张关联表,删除主表中已经在副表中没有的信息 363KU@`
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) z50P*
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11、说明:四表联查问题: 2!Qg1hM
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 ..... [9^lAhX
12、说明:日程安排提前五分钟提醒 ["^? vhv
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 <&RpGAk%I
13、说明:一条sql 语句搞定数据库分页 \2))c@@%
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 \,S4-~(:!
14、说明:前10条记录 RJ1@a
select top 10 * form table1 where 范围 Dbu>rESz
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.) ]?%S0DO*
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) g{^~g
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 +Ly@5y"
(select a from tableA ) except (select a from tableB) except (select a from tableC) b4&l=^:e=
17、说明:随机取出10条数据 ?DGg.2f
select top 10 * from tablename order by newid() QpD-%gN
18、说明:随机选择记录 jS ?#c+9
select newid() ShesJj
19、说明:删除重复记录 p""\uG'
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +"1fr
20、说明:列出数据库里所有的表名 MfZamu5+F
select name from sysobjects where type='U' bae;2| w
21、说明:列出表里的所有的 Y'<wE2ZL)
select name from syscolumns where id=object_id('TableName') 3Fw7q"
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。 '*B%&QC-
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 [vqf hpz
显示结果: Tq?7-_MLC$
type vender pcs ;pj,U!{%s\
电脑 A 1 @jCMQYR
电脑 A 1 " GY3sam
光盘 B 2 !bs5w_@
光盘 A 2 mw&'@M_(7
手机 B 3 8]mRX~
手机 C 3 B$M4f7
23、说明:初始化表table1 wk#cJ`wG;
TRUNCATE TABLE table1 lVCnu>8
24、说明:选择从10到15的记录 -tIye{
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc iPdS>ee
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三、技巧 }9kn;rb$g
1、1=1,1=2的使用,在SQL语句组合时用的较多 K@%gvLa\
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 1-$+@Xl
如: 2wu\.{6Zp
if @strWhere !='' dVg'v7G&V(
begin 5"y)<VLJX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere A4g,)
end K~4bT=
else cJf&R^[T
begin )t((x
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' orOq5?3
end EU
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我们可以直接写成 ~)F_FS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere osc A\r
2、收缩数据库 fZoQQ[s
--重建索引 [dFe-2u ,$
DBCC REINDEX \l%##7DRp]
DBCC INDEXDEFRAG a6@k*9D>
--收缩数据和日志 Po&'#TC1
DBCC SHRINKDB # [
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DBCC SHRINKFILE pedyWA>
3、压缩数据库 T"t.t%(8
dbcc shrinkdatabase(dbname) qI>,PX
4、转移数据库给新用户以已存在用户权限 yuC|_nL
exec sp_change_users_login 'update_one','newname','oldname' k!bG![Ie|
go Yxy!&hPLv:
5、检查备份集 9oIfSr,y
RESTORE VERIFYONLY from disk='E:\dvbbs.bak'
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6、修复数据库 hXvC>ie(i
ALTER DATABASE [dvbbs] SET SINGLE_USER qHgzgS7a
GO m#ig.z|A
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK `6RccEm
GO \r9E6LLX'
ALTER DATABASE [dvbbs] SET MULTI_USER #l h'
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GO Qsw.429t
7、日志清除 V CVKh
SET NOCOUNT ON nch#DE82
DECLARE @LogicalFileName sysname, Khl0 ~
@MaxMinutes INT, 6q8PLyIp
@NewSize INT r9*6=*J|
USE tablename -- 要操作的数据库名 YeVo=hYH@
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 EEMRy
@MaxMinutes = 10, -- Limit on time allowed to wrap log. \GV'{W+o2
@NewSize = 1 -- 你想设定的日志文件的大小(M) ;O|u`fAqT
-- Setup / initialize u@P1`E1Q
DECLARE @OriginalSize int OsW*@v(
SELECT @OriginalSize = size &bGf{P*Da
FROM sysfiles d,o*{sM5d
WHERE name = @LogicalFileName bN6i *)}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + )?I*zc
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + P,b&F
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' cltx(C>
FROM sysfiles qA[cF$CIl)
WHERE name = @LogicalFileName mN>(n+ly
CREATE TABLE DummyTrans Q+/P>5O/
(DummyColumn char (8000) not null) :sw@1
DECLARE @Counter INT, z`eMb
@StartTime DATETIME, GXk
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@TruncLog VARCHAR(255) f]mVM(XZN
SELECT @StartTime = GETDATE(), R\Ckk;<$
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' OI8}v
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Gx4{ 9
EXEC (@TruncLog) %eh.@8GL`
-- Wrap the log if necessary. ]826k pq_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired F>5b[q6~4
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 52NI{"
AND (@OriginalSize * 8 /1024) > @NewSize J qmL|S)
BEGIN -- Outer loop. ggrkj0
SELECT @Counter = 0 ;Wa&Dg/5`
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Jl6lZd(Np
BEGIN -- update x<OVtAUB
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans X 4!Jj*
SELECT @Counter = @Counter + 1 gyPwNE
END fW[RCd
EXEC (@TruncLog) rVRv*W
END
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + |DPq~l(d
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ms\\R@R
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 6!USSipn
FROM sysfiles jW4>WDN:
WHERE name = @LogicalFileName 5y] %Cu1.u
DROP TABLE DummyTrans MttFB;Tp
SET NOCOUNT OFF ]g }5p4*&
8、说明:更改某个表 G{O{
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exec sp_changeobjectowner 'tablename','dbo'
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9、存储更改全部表 ?>I
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch lgD%
@OldOwner as NVARCHAR(128),
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@NewOwner as NVARCHAR(128) :t;i2Ck
AS th<>%e}5c
DECLARE @Name as NVARCHAR(128) Oqt{ uTI~
DECLARE @Owner as NVARCHAR(128) T\ukJ25!
DECLARE @OwnerName as NVARCHAR(128) +JM@ kdE5b
DECLARE curObject CURSOR FOR "!fwIEG
select 'Name' = name, Ed{sC[j=
'Owner' = user_name(uid) Crl:v8
from sysobjects ^QG<_Dm]
where user_name(uid)=@OldOwner aR'~=t&;z1
order by name ori[[~OyB
OPEN curObject i2;,\FI@t%
FETCH NEXT FROM curObject INTO @Name, @Owner Vg :''!4t2
WHILE(@@FETCH_STATUS=0) 'NCx <0*
BEGIN VR%*8=
if @Owner=@OldOwner ,rF!o_7
begin 'H4?V
set @OwnerName = @OldOwner + '.' + rtrim(@Name) B2KBJ4rI[1
exec sp_changeobjectowner @OwnerName, @NewOwner FFe{=H,=
end ?<5KLvG v
-- select @name,@NewOwner,@OldOwner `B:hXeI
FETCH NEXT FROM curObject INTO @Name, @Owner rhX?\_7o
END TJ>1?W\Z
close curObject vA[7i*D{w
deallocate curObject ,7DyTeMpN
GO ?Iij[CbU
10、SQL SERVER中直接循环写入数据 XW\
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declare @i int 4Ss y (gt
set @i=1 %o0 H#7'
while @i<30 la4%Vqwgu
begin c,M"a
insert into test (userid) values(@i) G )`gn
set @i=@i+1 3+
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end \hb$v
小记存储过程中经常用到的本周,本月,本年函数 Ts|;5ya5m
Dateadd(wk,datediff(wk,0,getdate()),-1) 83p8:C.Ze
Dateadd(wk,datediff(wk,0,getdate()),6) F1L[C4'
Dateadd(mm,datediff(mm,0,getdate()),0) N3a ]!4Y\
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) T|j=,2_
Dateadd(yy,datediff(yy,0,getdate()),0) I)0_0JXs
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ]{#Xcqx
上面的SQL代码只是一个时间段 ?YDMl
Dateadd(wk,datediff(wk,0,getdate()),-1) =W2I0nr.
Dateadd(wk,datediff(wk,0,getdate()),6) O*x~a;?G
就是表示本周时间段. +
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下面的SQL的条件部分,就是查询时间段在本周范围内的: J4z&J SY
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Dkh=(+> <
而在存储过程中 x9 n(3Oa
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) - DYH>!
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) vQy<%[QO