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。 W
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一、基础 HJ_8 `( '
1、说明:创建数据库 "SA*
CREATE DATABASE database-name pCC3r t(
2、说明:删除数据库 adWH';Q:
drop database dbname A=+1PgL66
3、说明:备份sql server iyv5\
--- 创建 备份数据的 device 6&;h+;h
USE master D!V~g72j
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `4-N@h
--- 开始 备份 RpwDOG
BACKUP DATABASE pubs TO testBack eX$RD9
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4、说明:创建新表 T,9pd;k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) AD~_n^
根据已有的表创建新表: B8~bx%)3T
A:create table tab_new like tab_old (使用旧表创建新表) zyB>peAp6j
B:create table tab_new as select col1,col2... from tab_old definition only rpUTn!*u/
5、说明:删除新表 |pZ:5ta#
drop table tabname ny}_^3
6、说明:增加一个列 :7?n)=Tx
Alter table tabname add column col type H5(:1
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。 ](^FGz
7、说明:添加主键: Alter table tabname add primary key(col) &S39SV
说明:删除主键: Alter table tabname drop primary key(col) I23"DBR3
8、说明:创建索引:create [unique] index idxname on tabname(col....) ~(`&hYE
删除索引:drop index idxname NQcNY=
注:索引是不可更改的,想更改必须删除重新建。 aMJJ|iiU
9、说明:创建视图:create view viewname as select statement vDIsawbHD
删除视图:drop view viewname ^"iJ
10、说明:几个简单的基本的sql语句 cs 58: G5
选择:select * from table1 where 范围 K+|0~/0
插入:insert into table1(field1,field2) values(value1,value2) (QS 0
删除:delete from table1 where 范围 {s0!hp
更新:update table1 set field1=value1 where 范围 a1shP};pK
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! OkMAqS
排序:select * from table1 order by field1,field2 [desc] Gi\Z"MiBZ
总数:select count as totalcount from table1 SB`xr!~A]
求和:select sum(field1) as sumvalue from table1 P2F8[o!<
平均:select avg(field1) as avgvalue from table1 d~q7!
最大:select max(field1) as maxvalue from table1 32Wa{LG;2
最小:select min(field1) as minvalue from table1 !p Q*m`Xo
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11、说明:几个高级查询运算词 y!T8(
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A: UNION 运算符 M eYu
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。 %I;uqf
B: EXCEPT 运算符 ?:6w6GwAA
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。 Bkg./iP5x
C: INTERSECT 运算符 -b)3+#f
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。 +R_s(2vz
注:使用运算词的几个查询结果行必须是一致的。 "5v^6R9e
12、说明:使用外连接 NU"L1dK
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A、left outer join: 4n*`%V
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。 U|b)Bw<P
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 XePGOw))O
B:right outer join: eH~T PH
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。 rP#&WSLVj
C:full outer join: hcz!f
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。 `O!yt
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二、提升 ;M"[dy`dY
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) rH'|$~a
法一:select * into b from a where 1<>1 B>[myx
法二:select top 0 * into b from a $wbIe"|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) BY':R-~(
insert into b(a, b, c) select d,e,f from b; iu$Y0.H@
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) _YN
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 g9Ty%|Q7(
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. c<sq0('`
4、说明:子查询(表名1:a 表名2:b) 8T8]g 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) PAH#yM2Ic
5、说明:显示文章、提交人和最后回复时间 yyGn<
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Tfx-h)oP3
6、说明:外连接查询(表名1:a 表名2:b) >*\yEH9"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c g1 =>u
7、说明:在线视图查询(表名1:a ) nW`] =
select * from (SELECT a,b,c FROM a) T where t.a > 1; ^V7)V)Z;0
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 |pBvy1e4)
select * from table1 where time between time1 and time2 t^2$ent
select a,b,c, from table1 where a not between 数值1 and 数值2 >Bu_NoM
9、说明:in 的使用方法 wxN&k$`a
select * from table1 where a [not] in ('值1','值2','值4','值6') S4rm K&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 DQ&\k'"\
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Oc-ia)v1G
11、说明:四表联查问题: T-]UAN"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 ..... ZZYtaVF:
12、说明:日程安排提前五分钟提醒 w_DaldK*
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 s<oT,SPt
13、说明:一条sql 语句搞定数据库分页 PS0/Ok
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 cH5RpeP
14、说明:前10条记录 $j\jT
select top 10 * form table1 where 范围 ]=59_bkD:s
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.) 5H, (\Xd
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) i^8w0H<-@v
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 /B|"<`-H
(select a from tableA ) except (select a from tableB) except (select a from tableC) CAmIwAx6;
17、说明:随机取出10条数据 k5*Z@a
select top 10 * from tablename order by newid() 7%G&=8tq
18、说明:随机选择记录 _#uRKy<`N
select newid() jUDE)~h
19、说明:删除重复记录 YN~1.!F
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) uJ8FzS>[V
20、说明:列出数据库里所有的表名 BqM[{Kv
select name from sysobjects where type='U' =dmxE*C
21、说明:列出表里的所有的 O-box?
select name from syscolumns where id=object_id('TableName') x=X&b%09
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。 r?dkE=B
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 bR$5G
显示结果: 16Jjf|]j
type vender pcs FC
电脑 A 1 F%4N/e'L
电脑 A 1 4q(,uk&R[
光盘 B 2 K92M9=>
光盘 A 2 }:[MSUm5
手机 B 3 O&}R
手机 C 3 {Z1-B60P
23、说明:初始化表table1 %d<UMbS^
TRUNCATE TABLE table1 LR'~:46#u
24、说明:选择从10到15的记录 *}_i[6_\E
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc WI.+9$1:P
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三、技巧 nFe
1、1=1,1=2的使用,在SQL语句组合时用的较多 yo$A0Ti!w
"where 1=1" 是表示选择全部 "where 1=2"全部不选, >h~>7i(A
如: {hm-0Q
if @strWhere !='' *~w?@,}
begin SpOSUpl%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere %e_){28 n
end Mc,p]{<<AV
else b,'rz04^
begin QUg<~q)Oq
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Hl*#iUq
end lTFo#p_(
我们可以直接写成 ABL5T-*]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7M_GGjP
2、收缩数据库 \jS^+Xf?^
--重建索引 YG)7+94
DBCC REINDEX ,u!_mV
DBCC INDEXDEFRAG W)Y:2P<.
--收缩数据和日志 4VkJtu5
DBCC SHRINKDB lE*.9T
DBCC SHRINKFILE Ih;D-^RQ
3、压缩数据库 gKgdu($NJ
dbcc shrinkdatabase(dbname) R;uP^
4、转移数据库给新用户以已存在用户权限 *OHjw;xm+
exec sp_change_users_login 'update_one','newname','oldname' &(jt|?{
go ''k}3o.K[
5、检查备份集 ^K
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' iR8;^C.aT
6、修复数据库 Vg
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ALTER DATABASE [dvbbs] SET SINGLE_USER t+j dV
GO 3M'Y'Szm
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK y5Fgf3P@ju
GO LmUR@
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ALTER DATABASE [dvbbs] SET MULTI_USER ,S~A]uH'
GO 4 XGEw9`3
7、日志清除 pBn;:
SET NOCOUNT ON yA`,ns&n
DECLARE @LogicalFileName sysname, :K(+ KN(
@MaxMinutes INT, f917F.1I
@NewSize INT 2d<`dQY{l3
USE tablename -- 要操作的数据库名 Xob(4
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 .
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1KJ[&jS ]
@NewSize = 1 -- 你想设定的日志文件的大小(M) M?kXzb\O
-- Setup / initialize 5RY rAzQo
DECLARE @OriginalSize int 2%MS$Fto
SELECT @OriginalSize = size +!G)N~o
FROM sysfiles MW=rX>tE
WHERE name = @LogicalFileName J`wx72/-ZW
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "L9pFz</
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + U]ZI_[\'U
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 5z"
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FROM sysfiles ^Nysx ~6
WHERE name = @LogicalFileName s5X51#J#~
CREATE TABLE DummyTrans y@Td]6|f
(DummyColumn char (8000) not null) 6']WOM#
DECLARE @Counter INT, n.o_._mu2
@StartTime DATETIME, )Rj?\ZUR
@TruncLog VARCHAR(255) cO-^#di
SELECT @StartTime = GETDATE(), ("=24R=a
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Cio(Ptt:
DBCC SHRINKFILE (@LogicalFileName, @NewSize) wqyF"^It"
EXEC (@TruncLog) RVpo,;:
-- Wrap the log if necessary. a!PN`N28
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired } OkK@8?0O
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )1O|+m k
AND (@OriginalSize * 8 /1024) > @NewSize 8{Vt8>4
BEGIN -- Outer loop. CZ(fP86e
SELECT @Counter = 0 =CaSd|
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Owh:(EJ"d
BEGIN -- update 7}tXF
INSERT DummyTrans VALUES ('Fill Log') \x"BgLSE
DELETE DummyTrans <V#]3$(S
SELECT @Counter = @Counter + 1 K{ FBrh
END
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EXEC (@TruncLog) ,~NJ}4wP
END cOP%R_ak?
SELECT 'Final Size of ' + db_name() + ' LOG is ' + i^rHZmT
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + `<%
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' mrlhj8W?!
FROM sysfiles l585L3i
WHERE name = @LogicalFileName w}x&wWM
DROP TABLE DummyTrans h6D1uM"o
SET NOCOUNT OFF X C'|
8、说明:更改某个表 <h`}I3Ao
exec sp_changeobjectowner 'tablename','dbo' =z}M(<G
9、存储更改全部表 ZrWA,~;
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch gyCXv0*z
@OldOwner as NVARCHAR(128), >}86#^F
@NewOwner as NVARCHAR(128) ?nf4K/IjZ!
AS c2yZvi
DECLARE @Name as NVARCHAR(128) IY|>'}UU#
DECLARE @Owner as NVARCHAR(128) hTQ]xN)
DECLARE @OwnerName as NVARCHAR(128)
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DECLARE curObject CURSOR FOR u/5)Yx+5_
select 'Name' = name, DF"*[]^[
'Owner' = user_name(uid) So#>x5dL
from sysobjects ~B`H5#
where user_name(uid)=@OldOwner 1*B'o<?P1
order by name UR[UZ4G
OPEN curObject =AeOkie
FETCH NEXT FROM curObject INTO @Name, @Owner No]#RvEd3
WHILE(@@FETCH_STATUS=0) oCB#i~|>a
BEGIN w5a;ts_x
if @Owner=@OldOwner <@qJsRbhK
begin s18A
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Ia>~ph#]{`
exec sp_changeobjectowner @OwnerName, @NewOwner [Y6ZcO/-i
end gy/bA
-- select @name,@NewOwner,@OldOwner IZZ
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FETCH NEXT FROM curObject INTO @Name, @Owner ,*;g+[Bhpl
END ~&+8m=
close curObject G\*`%B_ n
deallocate curObject A)nE+ec1
GO n5?7iU&JIo
10、SQL SERVER中直接循环写入数据 ymA8`k5>@
declare @i int `(@{t:L
set @i=1 ABhQ7
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while @i<30 p1,.f&(f
begin z-`4DlJUS
insert into test (userid) values(@i) IVG77+O# }
set @i=@i+1 /ASpAl[J
end [uu<aRAg3O
小记存储过程中经常用到的本周,本月,本年函数 zB+zw\ncN
Dateadd(wk,datediff(wk,0,getdate()),-1) @G=_nZxv
Dateadd(wk,datediff(wk,0,getdate()),6) YU1z\pK
Dateadd(mm,datediff(mm,0,getdate()),0) f7 zGz
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) aOW$H:b
Dateadd(yy,datediff(yy,0,getdate()),0) ;7g~4Uv4}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <J!?eH9f
上面的SQL代码只是一个时间段 r6}-EYq=
Dateadd(wk,datediff(wk,0,getdate()),-1) 4pFoSs?\
Dateadd(wk,datediff(wk,0,getdate()),6) "%+9p6/
就是表示本周时间段. 6+yA4pRSd
下面的SQL的条件部分,就是查询时间段在本周范围内的: R%;dt<Dh
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8jgamG
而在存储过程中 !GZ{UmwA
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) tnw6[U!rh=
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) CSMx]jbb