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。 !aUs>1i
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一、基础 n9\TO9N
1、说明:创建数据库 G/E+L-N#`
CREATE DATABASE database-name KYm0@O>;
2、说明:删除数据库 &C_j\7Dq
drop database dbname $c!p&
3、说明:备份sql server A`%k:@
--- 创建 备份数据的 device U gat1Pz
USE master g&L!1<,
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' rI{; I DV
--- 开始 备份 Z-%\
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BACKUP DATABASE pubs TO testBack ic:zsuEm
4、说明:创建新表 G[ PtkPSJ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ScOK)nL"
根据已有的表创建新表: 38B2|x
A:create table tab_new like tab_old (使用旧表创建新表) 4>
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B:create table tab_new as select col1,col2... from tab_old definition only =jN.1}
5、说明:删除新表 b=C*W,Q_#
drop table tabname zpn9,,~u
6、说明:增加一个列 ,>a&"V^k
Alter table tabname add column col type fgTg7 m
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ^e,.
7、说明:添加主键: Alter table tabname add primary key(col) LBeF&sb6
说明:删除主键: Alter table tabname drop primary key(col) k t#fMd$
8、说明:创建索引:create [unique] index idxname on tabname(col....) u[;\y|75
删除索引:drop index idxname Q-oktRK
注:索引是不可更改的,想更改必须删除重新建。 xK[ou'
9、说明:创建视图:create view viewname as select statement Oi.C(@^(
删除视图:drop view viewname tAd%#:K
10、说明:几个简单的基本的sql语句 ,L2ZinU:
选择:select * from table1 where 范围 l\H=m3Bg
插入:insert into table1(field1,field2) values(value1,value2) ,&A7iO
删除:delete from table1 where 范围 RMV/&85?y
更新:update table1 set field1=value1 where 范围 Qp5VP@t
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ;+R&}[9,A)
排序:select * from table1 order by field1,field2 [desc] ^LnTOdAE
总数:select count as totalcount from table1 B3`5O[6
求和:select sum(field1) as sumvalue from table1 {lzWrUGO
平均:select avg(field1) as avgvalue from table1 gx/,)> E.
最大:select max(field1) as maxvalue from table1 =ZznFVJ`={
最小:select min(field1) as minvalue from table1 dES"@?!^
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11、说明:几个高级查询运算词 1s&zMWC
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A: UNION 运算符 yWc$>ne[L
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 tKuwpT1Qc
B: EXCEPT 运算符 "S]0
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 9<?M8_
C: INTERSECT 运算符 oSKXt}sh
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 2RX;Ob_
注:使用运算词的几个查询结果行必须是一致的。 HyQJXw?A:
12、说明:使用外连接 ]jQutlg|
A、left outer join: Wis~$"
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。 3pROf#M
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 ;4\2.*s
B:right outer join: ub0.J#j@
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。 ?zMHP#i
C:full outer join: <NY^M!
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。 `$IK`O
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二、提升 Lg+Ac5y}`
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +) om^e@.
法一:select * into b from a where 1<>1 H|<[YYk
法二:select top 0 * into b from a ;8&3 dm]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) NiEUW.0
insert into b(a, b, c) select d,e,f from b; RLXL&
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ,-LwtePJ0
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 +o{R _
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. M/'sl;
4、说明:子查询(表名1:a 表名2:b) [S%_In
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) wmL'F:UP
5、说明:显示文章、提交人和最后回复时间 UhWNl]Z
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )EuvRLo{S7
6、说明:外连接查询(表名1:a 表名2:b) HWrO"b*tO
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ua$GNm
7、说明:在线视图查询(表名1:a ) e]"W!KcD9
select * from (SELECT a,b,c FROM a) T where t.a > 1; Fyx|z'4b
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 {4}yKjW%z
select * from table1 where time between time1 and time2 pj{`';
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select a,b,c, from table1 where a not between 数值1 and 数值2 XEp{VC@=
9、说明:in 的使用方法 ]cWUZ{puRB
select * from table1 where a [not] in ('值1','值2','值4','值6') 4he GnMD
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Zn+.;o)E<
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %XDc,AR[
11、说明:四表联查问题: HZB>{O
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 ..... xrz,\eTb
12、说明:日程安排提前五分钟提醒 Sq V},
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 10~k2{Z
13、说明:一条sql 语句搞定数据库分页 /9*B)m"
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 $9#H04.x
14、说明:前10条记录 6<SAa#@ey
select top 10 * form table1 where 范围 %lhEM}Sm
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) c|y(2K)o[=
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /{l$sBUL
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 ,4e:I.b
(select a from tableA ) except (select a from tableB) except (select a from tableC) G6P?2@
17、说明:随机取出10条数据 H5B:;g@
select top 10 * from tablename order by newid() iC32nY?
18、说明:随机选择记录 ZY55|eE
select newid() P6`u._mX
19、说明:删除重复记录 iN\4gQ!
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) zkrM/ @p#
20、说明:列出数据库里所有的表名 4r#= *
select name from sysobjects where type='U' orpri O|qD
21、说明:列出表里的所有的 -HbC!wv
select name from syscolumns where id=object_id('TableName') [A~xy'T
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~2jmX
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 .t-4o<7 3
显示结果: VBGuC c/
type vender pcs 6Q@j
电脑 A 1 FaSf7D`C
电脑 A 1 $y &E(J
光盘 B 2 BwGfTua
光盘 A 2 Id'-&tYG
手机 B 3 =l;ewlU
手机 C 3 faX#**r
23、说明:初始化表table1 zpZm&WC
TRUNCATE TABLE table1 Ecefi
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24、说明:选择从10到15的记录 &K.d'$q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ]L $\
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三、技巧 &< `N T D
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?0?#U0(;u
"where 1=1" 是表示选择全部 "where 1=2"全部不选, QB uMJm
如: Ad8n<zt|
if @strWhere !='' wLH>:yKUU
begin bKY7/w<dP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere gIa+5\qYY
end )3}9K
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else ZRB)uA)5=
begin nI-w}NQ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' H3^},.
end n8
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我们可以直接写成 , , OW
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere !8d{q)JZ
2、收缩数据库 ["93~[[^
--重建索引 kk@fL
DBCC REINDEX x b~yM%*c
DBCC INDEXDEFRAG cWsNr'MS*
--收缩数据和日志 vhW2PzHFRi
DBCC SHRINKDB Xll}x+'uZK
DBCC SHRINKFILE O)*+="Rg
3、压缩数据库 O!#g<`r{K
dbcc shrinkdatabase(dbname) uAJx.>$b
4、转移数据库给新用户以已存在用户权限 NZLxHD]mp
exec sp_change_users_login 'update_one','newname','oldname' I<mV+ex
go 3g,`.I_
5、检查备份集 dI(@ZV{
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' :Zbg9`d*
6、修复数据库 jh%Eq+#S
ALTER DATABASE [dvbbs] SET SINGLE_USER x(6SG+Kr
GO Smn;(K
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK A@[o;H}XP
GO @ $ ;q;
ALTER DATABASE [dvbbs] SET MULTI_USER hHGoP0/o
GO U0y% u
7、日志清除 Eu d*_>|
SET NOCOUNT ON /wEhVR`=
DECLARE @LogicalFileName sysname, Ys!82M$g
@MaxMinutes INT, ^e _hLX\SW
@NewSize INT E)5\i-n
USE tablename -- 要操作的数据库名 *20jz<
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 EoR}Af
@MaxMinutes = 10, -- Limit on time allowed to wrap log. IqaT?+O\?r
@NewSize = 1 -- 你想设定的日志文件的大小(M) 3*"WG O5
-- Setup / initialize {0wIR_dGX
DECLARE @OriginalSize int t;}|tgC
SELECT @OriginalSize = size e "4 ''/
FROM sysfiles \5:i;AE
WHERE name = @LogicalFileName 5h=}j
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %~H-)_d20
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + DFB@O|JL
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' a`E#F]Z
FROM sysfiles q s6]-
WHERE name = @LogicalFileName p
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CREATE TABLE DummyTrans x_N'TjS^{
(DummyColumn char (8000) not null) x;P_1J%Q
DECLARE @Counter INT, .\ULbN3Z
@StartTime DATETIME, _?m(V=z>
@TruncLog VARCHAR(255) Eex~xiiV
SELECT @StartTime = GETDATE(), x:NY\._
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' S]e|"n~@
DBCC SHRINKFILE (@LogicalFileName, @NewSize) _~l5u8{^ 6
EXEC (@TruncLog) WdH$JTk1
-- Wrap the log if necessary. ;>EM[u
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired >=I|xY,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #4Rx]zW^%
AND (@OriginalSize * 8 /1024) > @NewSize TCwFPlF|
BEGIN -- Outer loop. o4F2%0gJ
SELECT @Counter = 0 +s,=lL
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 3=P]x;[ba
BEGIN -- update ~*&H$6NJS
INSERT DummyTrans VALUES ('Fill Log') NqazpB*
DELETE DummyTrans w7.V6S$Ga
SELECT @Counter = @Counter + 1 +K:Dx!9
END D09Sg%w
EXEC (@TruncLog) EPI4!3]
END #C74z$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + T= y}y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ,GbR!j@6
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' n`?aC|P2s
FROM sysfiles Db}j?ik/
WHERE name = @LogicalFileName ;40/yl3r3[
DROP TABLE DummyTrans Fx_z 6a
SET NOCOUNT OFF sk<3`x+
8、说明:更改某个表 FF`T\&u
exec sp_changeobjectowner 'tablename','dbo' 9X+V4xux
9、存储更改全部表 wj$<t'MN
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch `_Zg3_K.dS
@OldOwner as NVARCHAR(128), .nf#c.DI
@NewOwner as NVARCHAR(128) wY{-BuXv
AS .=7vI$ujd
DECLARE @Name as NVARCHAR(128) Mlg0WrJ|2
DECLARE @Owner as NVARCHAR(128) L2[($l
DECLARE @OwnerName as NVARCHAR(128) hc(#{]].
DECLARE curObject CURSOR FOR KEo,m
select 'Name' = name, ios&n)W&
'Owner' = user_name(uid) <SAzxo:I
from sysobjects *MFIV02[N
where user_name(uid)=@OldOwner 7?!d^$B
order by name ed{ -/l~j
OPEN curObject z [}v{
FETCH NEXT FROM curObject INTO @Name, @Owner .]Y$o^mf
WHILE(@@FETCH_STATUS=0) ;C9_?u~#
BEGIN 4<w.8rR:A
if @Owner=@OldOwner JQ_sUYh~3
begin #>("CAB02T
set @OwnerName = @OldOwner + '.' + rtrim(@Name) twHVv
exec sp_changeobjectowner @OwnerName, @NewOwner )5Q~I,dP
end YlJ@XpKM
-- select @name,@NewOwner,@OldOwner lV3x *4O=
FETCH NEXT FROM curObject INTO @Name, @Owner Fh&G;aEq
END Wa>}wA=v
close curObject lwxaMjaL4K
deallocate curObject d`=MgHz
GO FJGlP&v<
10、SQL SERVER中直接循环写入数据 `!3SF|x&
declare @i int @|Cz-J;D
set @i=1 Tt`u:ZwhF
while @i<30 #'nr
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begin P+
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insert into test (userid) values(@i) xf\ C|@i
set @i=@i+1 e9Wa<i8
end hE'-is@7
小记存储过程中经常用到的本周,本月,本年函数 4$HhP,gL=
Dateadd(wk,datediff(wk,0,getdate()),-1) )
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Dateadd(wk,datediff(wk,0,getdate()),6) <Uk}o8E
Dateadd(mm,datediff(mm,0,getdate()),0) P-9)38`5
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) kr^P6}'
Dateadd(yy,datediff(yy,0,getdate()),0) htO+z7
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Y!aSs3c
上面的SQL代码只是一个时间段 kUL'1!j7
Dateadd(wk,datediff(wk,0,getdate()),-1) RtkEGxw*^
Dateadd(wk,datediff(wk,0,getdate()),6) /Y:sLGQLD
就是表示本周时间段. WH#1zv
下面的SQL的条件部分,就是查询时间段在本周范围内的: > ym,{EHK
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) P[G)sA_"
而在存储过程中 kf\PioD8
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) l?v86k
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) jodIv=C