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。 X@@7Qk
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一、基础 @}A3ie'w
1、说明:创建数据库 ?4lEHef
CREATE DATABASE database-name
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2、说明:删除数据库 ZrDr/Q~
drop database dbname .&n;S';"
3、说明:备份sql server OBZ:C!
--- 创建 备份数据的 device e1 P(-V
USE master jGOE
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' W^1)70<y
--- 开始 备份 {tF)%>\#
BACKUP DATABASE pubs TO testBack M7\K iQd
4、说明:创建新表 Cq<k(TKAX
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) + :k"{I
根据已有的表创建新表: Rj/ y.g
A:create table tab_new like tab_old (使用旧表创建新表) :X#'ELo|
B:create table tab_new as select col1,col2... from tab_old definition only p`oHF 5
5、说明:删除新表 Ve\P ,.
drop table tabname LKu
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6、说明:增加一个列 g42Z*+P6N
Alter table tabname add column col type v^(J+d_>
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。 NpF)|Ppb{
7、说明:添加主键: Alter table tabname add primary key(col) =42NQ{%@;
说明:删除主键: Alter table tabname drop primary key(col) o\:vxj+%*
8、说明:创建索引:create [unique] index idxname on tabname(col....) p (x<h
删除索引:drop index idxname (KdP^.7
注:索引是不可更改的,想更改必须删除重新建。 U#F(%b-LC
9、说明:创建视图:create view viewname as select statement K7]IAV
删除视图:drop view viewname ,:?=j80m
10、说明:几个简单的基本的sql语句 R ;3!?`
选择:select * from table1 where 范围 7N[Cs$_]
插入:insert into table1(field1,field2) values(value1,value2) <=PYu:]h
删除:delete from table1 where 范围 !_j6\r=
更新:update table1 set field1=value1 where 范围 4F?O5&329i
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! kaZ_ra;<
排序:select * from table1 order by field1,field2 [desc] kDK0L3}nr]
总数:select count as totalcount from table1 5tm:|.`SQ
求和:select sum(field1) as sumvalue from table1 >Gxh=**F
平均:select avg(field1) as avgvalue from table1 qre(3,VE5
最大:select max(field1) as maxvalue from table1 }n$I #G}\/
最小:select min(field1) as minvalue from table1 84M*)cKR~
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11、说明:几个高级查询运算词 a
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A: UNION 运算符
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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。 K8|>" c~
B: EXCEPT 运算符 CeW}zkcT
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。 l08JL
C: INTERSECT 运算符 BMovl4*5
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。 xY1@Ja
注:使用运算词的几个查询结果行必须是一致的。 _gI1@uQw
12、说明:使用外连接 ed4`n!3
A、left outer join: ;$rh&ET
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 LFPYnK
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c i$S*5+
B:right outer join: Kma-W{vGD
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。 ;@G5s+<l
C:full outer join: h&m4"HBL_
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。 $o>6Io|D
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二、提升 2, r{zJ8
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) vy1N,8a
法一:select * into b from a where 1<>1 R#Hz%/:|A
法二:select top 0 * into b from a TWTh!
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) P_%kYcX'
insert into b(a, b, c) select d,e,f from b; rZ^VKO`~I1
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ,U#FtOec
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 spv'r!*\ed
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +]jJ: V
4、说明:子查询(表名1:a 表名2:b) 4+4C0/$Y
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) WS1$cAD2N
5、说明:显示文章、提交人和最后回复时间 : tcqb2p
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b C9"yu&l
6、说明:外连接查询(表名1:a 表名2:b) |A19IXZ\
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c a
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7、说明:在线视图查询(表名1:a ) LQ.0"6oj
select * from (SELECT a,b,c FROM a) T where t.a > 1; b?%Pa\,!
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 /^9yncG;>
select * from table1 where time between time1 and time2 WTQd}f
select a,b,c, from table1 where a not between 数值1 and 数值2 <<[\
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9、说明:in 的使用方法 -JfO} DRI
select * from table1 where a [not] in ('值1','值2','值4','值6') A6%~+9
10、说明:两张关联表,删除主表中已经在副表中没有的信息 73>Hzpv0
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) -q}I;
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11、说明:四表联查问题: 9Ts r g
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 ..... YTYCv7
12、说明:日程安排提前五分钟提醒 e?
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 &<oDl_^
13、说明:一条sql 语句搞定数据库分页 #i0f}&
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 rEG!A87Zz
14、说明:前10条记录 EawtT
select top 10 * form table1 where 范围 PHQ99&F1
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.) pm k;5 d
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 37nGFH`K2m
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 \K(QE ~y'W
(select a from tableA ) except (select a from tableB) except (select a from tableC) |FxTP&8~
17、说明:随机取出10条数据 bd@1j`i
select top 10 * from tablename order by newid() HC/?o0
18、说明:随机选择记录 s.9_/cFWB
select newid() rWD*DmY@"
19、说明:删除重复记录 ^)0b= (.
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +a}>cAj*
20、说明:列出数据库里所有的表名 DS6g_SS3
select name from sysobjects where type='U' +n&9ZCH
21、说明:列出表里的所有的 }ec3qZ@
select name from syscolumns where id=object_id('TableName') <J.-fZS%
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。 E.+BqWZ!
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 $ J)2E g
显示结果: O>kM2xw
type vender pcs 0rj50$~$]
电脑 A 1 Xhm)K3RA*T
电脑 A 1 RoeLf Ow
光盘 B 2 e{7"7wn=
光盘 A 2 ( t59SY
手机 B 3 mVdg0
手机 C 3 p| o?nI
23、说明:初始化表table1 L#9g ~>~
TRUNCATE TABLE table1 Vf] ;hm
24、说明:选择从10到15的记录 g.d~`R@v
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc qhqqCVrsW
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三、技巧 \2NT7^H#
1、1=1,1=2的使用,在SQL语句组合时用的较多 N(=\S:
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 19 <Lgr
如: +N:=|u.g
if @strWhere !='' eL{6;.C
begin 5;Q9Z1
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere (|U|>@
end dId&tTMmC
else `sPH7^R
begin ewORb
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 4+'d">+|
end u:GDM
我们可以直接写成 6R+EG{`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere wTkcR^
2、收缩数据库 HA0Rv#p
--重建索引 *zTEK:+_
DBCC REINDEX qjI.Sr70
DBCC INDEXDEFRAG {axMS yp;
--收缩数据和日志 G+zIh}9
DBCC SHRINKDB FCA]zR1
DBCC SHRINKFILE 2}jC%jR2
3、压缩数据库 xI(Y}>
dbcc shrinkdatabase(dbname) Yo;Mexo!
4、转移数据库给新用户以已存在用户权限 l~c# X3E
exec sp_change_users_login 'update_one','newname','oldname' U t'r^
go ]B>g~t5J
5、检查备份集 ERZWK
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' d<+@cf_9
6、修复数据库 {&d )O
ALTER DATABASE [dvbbs] SET SINGLE_USER `;\~$^sj}
GO E
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK VSW"/{Lp
GO Zz@wbhMV
ALTER DATABASE [dvbbs] SET MULTI_USER bFtzwa5Gc
GO Ab/KVB
7、日志清除 ZtH{2j0
SET NOCOUNT ON atmTI`i
DECLARE @LogicalFileName sysname, h&j9'
@MaxMinutes INT, _5&LV2
@NewSize INT CGY,I
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USE tablename -- 要操作的数据库名 Xw_6SR9C
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 f5dctDHP
@MaxMinutes = 10, -- Limit on time allowed to wrap log. OXIy0].b
@NewSize = 1 -- 你想设定的日志文件的大小(M) nHTb~t5Ke
-- Setup / initialize 0o&B 7N
DECLARE @OriginalSize int \>nY%*
SELECT @OriginalSize = size yi@mf$A|
FROM sysfiles TDR2){I
WHERE name = @LogicalFileName (Q~(t
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 6*tbil_G+
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + &=`6- J
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z)0%gd|
FROM sysfiles $mLiEsJ
WHERE name = @LogicalFileName v7@O ,%
CREATE TABLE DummyTrans @1^:V-=
(DummyColumn char (8000) not null) E!zAUEVQm[
DECLARE @Counter INT, T,SCK^
@StartTime DATETIME, "pW@[2Dkx/
@TruncLog VARCHAR(255) /o]j
SELECT @StartTime = GETDATE(), Jl|^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2E_*'RT
DBCC SHRINKFILE (@LogicalFileName, @NewSize) DX#_0-o
EXEC (@TruncLog) G;Thz
-- Wrap the log if necessary. !:|[?M.`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired fw+ VR.#2H
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) X'XH-E
AND (@OriginalSize * 8 /1024) > @NewSize k*Vf2O3${
BEGIN -- Outer loop. "'\f?A9
SELECT @Counter = 0 XX|wle1Kg
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) F-I\x
BEGIN -- update pSh$#]mZ`
INSERT DummyTrans VALUES ('Fill Log') ti}G/*4
DELETE DummyTrans 11jDAA(|
SELECT @Counter = @Counter + 1 \(a!U,]LM
END tFKR~?Gc
EXEC (@TruncLog) &j_:VP
END #7yy7Y5
SELECT 'Final Size of ' + db_name() + ' LOG is ' + AagWswv{Bf
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ("-`Y'"K
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' nps"nggk
FROM sysfiles 5X=ik7m^
WHERE name = @LogicalFileName @#W$7Gwf0
DROP TABLE DummyTrans 8bP4
SET NOCOUNT OFF >
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8、说明:更改某个表 9a;8^?Ld%S
exec sp_changeobjectowner 'tablename','dbo' &nX,)"
9、存储更改全部表 =as\Tp#d
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch t?404
@OldOwner as NVARCHAR(128), )o>1=Y`[z
@NewOwner as NVARCHAR(128) ?7CHHk
AS R4P$zB_<2
DECLARE @Name as NVARCHAR(128) DA-W =Cc
DECLARE @Owner as NVARCHAR(128) O| zLD
DECLARE @OwnerName as NVARCHAR(128) X"p p l7o
DECLARE curObject CURSOR FOR 1l`$. k
select 'Name' = name, <;.->73E
'Owner' = user_name(uid) 5*31nMP\
from sysobjects %zA$+eT
where user_name(uid)=@OldOwner \~ql_X;3
order by name 4bZ
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OPEN curObject .e8S^lSl
FETCH NEXT FROM curObject INTO @Name, @Owner Owz.C_{)
WHILE(@@FETCH_STATUS=0) b1 NB:
BEGIN 'I *&P5|
if @Owner=@OldOwner p&4#9I5
begin @mu2,%
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 1[Ffl^\ARp
exec sp_changeobjectowner @OwnerName, @NewOwner JD1D(
end $bi@,&t;
-- select @name,@NewOwner,@OldOwner I}{Xv#@o
FETCH NEXT FROM curObject INTO @Name, @Owner p-1
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END #w:6<$
close curObject [d~25
deallocate curObject Y%iimbBY|
GO BpQ/$?5E"
10、SQL SERVER中直接循环写入数据 875BD U
declare @i int '#faNVPABh
set @i=1 Wr+1G 8
while @i<30 d[Lr`=L;
begin ,)JSXo
insert into test (userid) values(@i) 2r~&+0sBP
set @i=@i+1 ]\_T
end YDMimis\H5
小记存储过程中经常用到的本周,本月,本年函数 Jxy94y*
Dateadd(wk,datediff(wk,0,getdate()),-1) b 7%O[
Dateadd(wk,datediff(wk,0,getdate()),6) l-mf~{
Dateadd(mm,datediff(mm,0,getdate()),0) QC\][I>
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) |+0XO?,sZ
Dateadd(yy,datediff(yy,0,getdate()),0) `!$I6KxT
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) z}[qk:
上面的SQL代码只是一个时间段 Qy+&N*k>
Dateadd(wk,datediff(wk,0,getdate()),-1) td6$w:SN,l
Dateadd(wk,datediff(wk,0,getdate()),6) Sn lKPd
就是表示本周时间段. &R
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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: A+Xk=k5<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) [# '38
而在存储过程中 {,aI0bw;
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) l[EjtN
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ?]#U~M<'