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。 ~Hu!iZ2]
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一、基础 I]DD5l}\
1、说明:创建数据库 g+5c"Yk+u~
CREATE DATABASE database-name LM+d3|gSV
2、说明:删除数据库 C}(@cn `L
drop database dbname Y%eq2%
3、说明:备份sql server Vn_~ |-Wt
--- 创建 备份数据的 device Kk*8
USE master l*6Zh"o:
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' #wo
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--- 开始 备份 \h_q]
BACKUP DATABASE pubs TO testBack xH&hs$=
4、说明:创建新表 wJNm}Wf
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) !-.GfI:q
根据已有的表创建新表: OQ-
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A:create table tab_new like tab_old (使用旧表创建新表) hf^<lJh~=
B:create table tab_new as select col1,col2... from tab_old definition only :m(DRD
5、说明:删除新表 '_^T]fr}
drop table tabname z:@:B:E
6、说明:增加一个列 {}$Zff
Alter table tabname add column col type 0|J_'-<
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。 7}g4ePYag
7、说明:添加主键: Alter table tabname add primary key(col) |Fi5/$S.
说明:删除主键: Alter table tabname drop primary key(col) 1`YU9?
8、说明:创建索引:create [unique] index idxname on tabname(col....) 5mC"8N1)
删除索引:drop index idxname DzQ
注:索引是不可更改的,想更改必须删除重新建。 </WeB3#6
9、说明:创建视图:create view viewname as select statement xDGS`o_w_
删除视图:drop view viewname Fs].Fa
10、说明:几个简单的基本的sql语句 TN1pg
选择:select * from table1 where 范围 N0.|Mb"?t
插入:insert into table1(field1,field2) values(value1,value2) E5$]0#jB
删除:delete from table1 where 范围 ?3p7MjvZ
更新:update table1 set field1=value1 where 范围 ;AE-=/<
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4(|yl^w
排序:select * from table1 order by field1,field2 [desc] nYFrp)DLK
总数:select count as totalcount from table1 wD=]U@t`,
求和:select sum(field1) as sumvalue from table1 YZj*F-}
平均:select avg(field1) as avgvalue from table1 NC#F:M;b
最大:select max(field1) as maxvalue from table1 s2#Ia>5!
最小:select min(field1) as minvalue from table1 i'7+
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11、说明:几个高级查询运算词 ](A2,F
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A: UNION 运算符 xbm%+
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%(l,
B: EXCEPT 运算符 l6y}>]
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。 W3:Fw6v
C: INTERSECT 运算符 nuXL{tg6
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。 0]kKF<s
注:使用运算词的几个查询结果行必须是一致的。 sl `jovT[Y
12、说明:使用外连接 p,goYF??
A、left outer join: lQ-<T<g
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。 Jsysk $R
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !R"W2 Z4h
B:right outer join: \gk.[={^P
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 l2qvYNMw
C:full outer join: D]]wJQU2
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 viG,z4Zf
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二、提升 kIVQ2hmv
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) H*'1bLzq
法一:select * into b from a where 1<>1 iCE!TmDT
法二:select top 0 * into b from a jYFJk&c
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \&5V';
insert into b(a, b, c) select d,e,f from b; MQQm3VaKS
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) R7kkth
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 `oJQA$UD
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. m{/(
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4、说明:子查询(表名1:a 表名2:b) %bAQ>E2;m
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) +cfEyiub
5、说明:显示文章、提交人和最后回复时间 G{3|d/;Bt
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b W<r<K=`5P
6、说明:外连接查询(表名1:a 表名2:b) [b:&y(
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c P[2!D)A
7、说明:在线视图查询(表名1:a ) T&?g)
select * from (SELECT a,b,c FROM a) T where t.a > 1; NOo?
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 (Jk&U8y
select * from table1 where time between time1 and time2 q(6.VU@
select a,b,c, from table1 where a not between 数值1 and 数值2 n^Ca?|}
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9、说明:in 的使用方法 YV<y-,Io
select * from table1 where a [not] in ('值1','值2','值4','值6') |oi+|r
10、说明:两张关联表,删除主表中已经在副表中没有的信息 #wI}93E
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ?T/]w-q>
11、说明:四表联查问题: YQn<CjZ8af
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 ..... "XR=P>
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12、说明:日程安排提前五分钟提醒 wlT8|
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 STp9Gh-
13、说明:一条sql 语句搞定数据库分页 L~Gr,i
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 #h5lz%2g
14、说明:前10条记录 `RL
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select top 10 * form table1 where 范围 uiVNz8H
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.) L"qJZU
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) dU$VRgP/
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ; :P4~R
(select a from tableA ) except (select a from tableB) except (select a from tableC) 2'DCB{Jv
17、说明:随机取出10条数据 )l7XZ_gw'
select top 10 * from tablename order by newid() Vxh39eW
18、说明:随机选择记录 ]YgR
select newid() >fH0>W+!
19、说明:删除重复记录 "' JnFM
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
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20、说明:列出数据库里所有的表名 |9#q7kM
select name from sysobjects where type='U' {A/r)
21、说明:列出表里的所有的 -&Z!b!jN
select name from syscolumns where id=object_id('TableName') w+g29
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 y9r4]45
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type >}+{;d
显示结果: fg^AEn1i
type vender pcs #ibwD:{
电脑 A 1 fp)SZu_*
电脑 A 1 g2vm]j
光盘 B 2 HwUaaK
光盘 A 2 ?woL17Gt
手机 B 3 wa"0`a:`;
手机 C 3 rwRZGd *p
23、说明:初始化表table1 ^dI;B27E*
TRUNCATE TABLE table1 CS7b3p!I
24、说明:选择从10到15的记录 u>*a@3$f
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 'J,UKK\5
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三、技巧 /)ZjI
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1、1=1,1=2的使用,在SQL语句组合时用的较多 FDMQLx f
"where 1=1" 是表示选择全部 "where 1=2"全部不选, jHFjd'
如: 0D(8-H
if @strWhere !='' Lce,]z\_
begin g\q .
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere xMJ-=
end +
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else D+]mKPB
begin f%]@e9dD
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' -9b=-K.y
end \p4*Q}t
我们可以直接写成 ~H}Z;n]H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Kxsd@^E
2、收缩数据库 ?"yjgt7+y
--重建索引 ^E70$yB^
DBCC REINDEX yKML{N1D
DBCC INDEXDEFRAG 8<VDp Y
--收缩数据和日志 !db=Iz5)
DBCC SHRINKDB :3D8rqi:
DBCC SHRINKFILE JHxcHh
3、压缩数据库 TGJz[Ny
dbcc shrinkdatabase(dbname) ht-'O"d:
4、转移数据库给新用户以已存在用户权限 REh"/d
exec sp_change_users_login 'update_one','newname','oldname' 5U2%X
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go Et 0gPX-
5、检查备份集 '.v;/[0
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -wn-PB@r
6、修复数据库 +~5Lo'^
ALTER DATABASE [dvbbs] SET SINGLE_USER o?a2wY^_
GO L4 po1
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 0~nX7
GO +6WjOcu
ALTER DATABASE [dvbbs] SET MULTI_USER V^s, 3C
GO .\b.l@O<Z
7、日志清除 .x=abA$!9
SET NOCOUNT ON jJ2rfdfj
DECLARE @LogicalFileName sysname, ?p{-Yp*h
@MaxMinutes INT, OLG)D#m(4/
@NewSize INT rmjuNy=(
USE tablename -- 要操作的数据库名 1I2ndt
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 C6e5*S
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Ftyxz&-4$p
@NewSize = 1 -- 你想设定的日志文件的大小(M) zZ[kU1Fyv
-- Setup / initialize so` \e^d
DECLARE @OriginalSize int Xe4
SELECT @OriginalSize = size qsj$u-xhX
FROM sysfiles L` [iI
WHERE name = @LogicalFileName upMs yLp(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Y1Ql_
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {MtJP:8Jp
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' r*{.|>me
FROM sysfiles 7{r7
WHERE name = @LogicalFileName k)+{Y v*
CREATE TABLE DummyTrans }hn?4ny
(DummyColumn char (8000) not null) /[/L%;a'p
DECLARE @Counter INT, Ku'a,\7z
@StartTime DATETIME, (cVIjo+::
@TruncLog VARCHAR(255) t ]BG)]
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ub?dfS9$_
DBCC SHRINKFILE (@LogicalFileName, @NewSize) pW[TufTa
EXEC (@TruncLog) q>%B @'
-- Wrap the log if necessary. PS~_a
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired YMo8C(
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) %RW*gUvc]
AND (@OriginalSize * 8 /1024) > @NewSize (\qf>l+*
BEGIN -- Outer loop. 5B~]%_gZr
SELECT @Counter = 0 TFHYB9vV
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) @kSfF[4H
BEGIN -- update ZKI8x1>Iq
INSERT DummyTrans VALUES ('Fill Log') Q%6zr9
DELETE DummyTrans D&fOZVuqZ
SELECT @Counter = @Counter + 1 =bp'5h8_
END /%g@ ;
EXEC (@TruncLog) ~vYFQKrb
END EuHQp7
SELECT 'Final Size of ' + db_name() + ' LOG is ' + );HhV,$n
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + z^wod
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' p4uzw
FROM sysfiles U>n[R/~]
WHERE name = @LogicalFileName ,L%]}8EL"
DROP TABLE DummyTrans M[985bl
SET NOCOUNT OFF ~JRq :
8、说明:更改某个表 `"~GqFwy~
exec sp_changeobjectowner 'tablename','dbo' |g hyH
9、存储更改全部表 +_X*one
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ?jmL4V2-f
@OldOwner as NVARCHAR(128), uBG!R#T
@NewOwner as NVARCHAR(128) mBL?2~M
AS g8/ ,E-u
DECLARE @Name as NVARCHAR(128) eJf]"-
DECLARE @Owner as NVARCHAR(128) 8A0a/
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DECLARE @OwnerName as NVARCHAR(128) wtbN@g0
DECLARE curObject CURSOR FOR rrC\4#H[??
select 'Name' = name, q"269W:
'Owner' = user_name(uid) |zRrGQYm
from sysobjects BuvnY
where user_name(uid)=@OldOwner kh}h(z^
order by name fbM>jK
OPEN curObject n:a~=^IV
FETCH NEXT FROM curObject INTO @Name, @Owner MHp:".1
WHILE(@@FETCH_STATUS=0) A p zC
BEGIN zjH8S
if @Owner=@OldOwner D_(NLC
begin `)$G}7cRUH
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 8i^
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exec sp_changeobjectowner @OwnerName, @NewOwner n+
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end pa^_D~
-- select @name,@NewOwner,@OldOwner H{*rV>%
FETCH NEXT FROM curObject INTO @Name, @Owner |J@
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END VOYQ<tg
close curObject ydVDjE
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deallocate curObject Jr'a_(~
GO +b_[JP2
10、SQL SERVER中直接循环写入数据 V}`ri~
declare @i int ]?V:+>t=
set @i=1 07=I&Pum
while @i<30 k^d^Todq.
begin qQfNT.
insert into test (userid) values(@i) pSAtn
set @i=@i+1 ,n%b~.$:v5
end O,7S1
小记存储过程中经常用到的本周,本月,本年函数 3;jxIo$,
Dateadd(wk,datediff(wk,0,getdate()),-1) u[SqZftmO
Dateadd(wk,datediff(wk,0,getdate()),6)
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Dateadd(mm,datediff(mm,0,getdate()),0) Ne;0fkO
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7'At_oG
Dateadd(yy,datediff(yy,0,getdate()),0) nWc@ufY
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) eKuF7Oo
上面的SQL代码只是一个时间段 Sz|kXk6&9
Dateadd(wk,datediff(wk,0,getdate()),-1) $[Ut])4
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Dateadd(wk,datediff(wk,0,getdate()),6) .p Mwa
就是表示本周时间段. :W>PKW`^
下面的SQL的条件部分,就是查询时间段在本周范围内的: J(8?6&=ck
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 2xUgM}e
而在存储过程中 "3 ++S
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) KL!cPnAUu
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) \HrtPm`e