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。 OpUfK4U)
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一、基础 7*5B
1、说明:创建数据库 *4cuWkQ,
CREATE DATABASE database-name ^{+ry<rS>
2、说明:删除数据库 6R6Ub
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drop database dbname $p0nq&4c
3、说明:备份sql server AWR :~{
--- 创建 备份数据的 device 2}vibDq p
USE master )0"Q
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' d6luksO*9
--- 开始 备份 <|Td0|x
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BACKUP DATABASE pubs TO testBack cI=6zMB
4、说明:创建新表 >;fVuy
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) OdzeHpH3g
根据已有的表创建新表: /%T/@y
A:create table tab_new like tab_old (使用旧表创建新表) !m@cTB7i
B:create table tab_new as select col1,col2... from tab_old definition only Ds`e-X)O;\
5、说明:删除新表 smn"]K
drop table tabname MpCPY"WLL
6、说明:增加一个列 !7N:cx'Qy
Alter table tabname add column col type 11H`WOTQF
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 L<F8+a7i
7、说明:添加主键: Alter table tabname add primary key(col) :R;w<Tbz"
说明:删除主键: Alter table tabname drop primary key(col) s6`E.Eevm
8、说明:创建索引:create [unique] index idxname on tabname(col....) V"/.An|
删除索引:drop index idxname xVx s~p1
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement 2.q Zs8&
删除视图:drop view viewname |a(KVo
10、说明:几个简单的基本的sql语句 VeA@HC`?"
选择:select * from table1 where 范围 ^)AECn
插入:insert into table1(field1,field2) values(value1,value2) ='7m$,{(Q[
删除:delete from table1 where 范围 -$d?e%}#
更新:update table1 set field1=value1 where 范围 c#OxI*,+/
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! noZbsI4
排序:select * from table1 order by field1,field2 [desc] t7Q$
总数:select count as totalcount from table1 Y)rK'OY'
求和:select sum(field1) as sumvalue from table1 -^@FZR^Y
平均:select avg(field1) as avgvalue from table1 V%,,GmiU]
最大:select max(field1) as maxvalue from table1 /Ew()>Y
最小:select min(field1) as minvalue from table1 {?qfH>oFA
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11、说明:几个高级查询运算词 VI!
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A: UNION 运算符 >q}3#TvP@
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。 0Wr<l%M)+
B: EXCEPT 运算符 T\6Qr$t
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 2I.FSR_G?
C: INTERSECT 运算符 JX59n%$@
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。 K9<8FSn
注:使用运算词的几个查询结果行必须是一致的。 pS?D~0Nb
12、说明:使用外连接 (XZ[-M7
A、left outer join: 7e<=(\(yl
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。 A4j,]hOD
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 odP<S.
B:right outer join: 1iT_mtXK$
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。 TegdB|y7O
C:full outer join: j*%#~UFw
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。 1$*8F
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二、提升 W~ yb>+u
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) x\yM|WGL
法一:select * into b from a where 1<>1 {cdICWy(F3
法二:select top 0 * into b from a bmT%?it
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) m$8siF{<q
insert into b(a, b, c) select d,e,f from b; #qd!_oN
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) >tg)F|@
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Ws2q/[\oz
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. `m 5\
4、说明:子查询(表名1:a 表名2:b) Es=G' au
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) [@K'}\U^+
5、说明:显示文章、提交人和最后回复时间 H1N@E}> |
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (kL"*y/"p
6、说明:外连接查询(表名1:a 表名2:b) @nH3nn
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c w-).HPe
7、说明:在线视图查询(表名1:a ) vn.5X
select * from (SELECT a,b,c FROM a) T where t.a > 1; \'O/3Y7?X
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 )<x9t@$
select * from table1 where time between time1 and time2 [}L?EM
select a,b,c, from table1 where a not between 数值1 and 数值2 0:{W
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9、说明:in 的使用方法 Bc=(1ty)
select * from table1 where a [not] in ('值1','值2','值4','值6') @]Q4K%1^"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 xU;SRB
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0akJv^^D
11、说明:四表联查问题: l+;S$evY
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 ..... Au2^ T1F
12、说明:日程安排提前五分钟提醒 eD*764tG
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 D0J{pAJ
13、说明:一条sql 语句搞定数据库分页 %|jS`kj
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 `^#Rwn#
14、说明:前10条记录 iwnGWGcuS
select top 10 * form table1 where 范围 r\m{;Z#LJm
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.) ,2AulX1
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Lg\3DzM
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 w1<pQ[A
(select a from tableA ) except (select a from tableB) except (select a from tableC) +*.*bo
17、说明:随机取出10条数据 dv.
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select top 10 * from tablename order by newid() TOiLv.Dor
18、说明:随机选择记录 cqU6 Y*n
select newid() [n9l[dN
19、说明:删除重复记录 M^ *~?9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) a`Bp^(f}
20、说明:列出数据库里所有的表名 @3n!5XM{EE
select name from sysobjects where type='U' nOC\ =<Nsg
21、说明:列出表里的所有的 V lZ+x)E
select name from syscolumns where id=object_id('TableName') $_JfM^w
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。 U&"L9o`2
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 EWJB/iED
显示结果: jdG'sITv
type vender pcs J{/hc}
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电脑 A 1 \Fjasz5E'
电脑 A 1 1c,#`\Iikd
光盘 B 2 gwB,*.z
光盘 A 2 bWL!=
手机 B 3 }P.s
手机 C 3
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23、说明:初始化表table1 F6vsU:TfB
TRUNCATE TABLE table1 :h@V,m Z
24、说明:选择从10到15的记录 %LnLB
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >V.?XZ nt
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三、技巧 **P P
1、1=1,1=2的使用,在SQL语句组合时用的较多 /[c_,G""
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Qi\]='C
如: g_4%M0&AX
if @strWhere !='' EG4~[5[YgI
begin .i\FK@2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ;)ay uS sQ
end H[w';u[%
else dpz@T>MS=
begin FqyxvL.
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ,{IDf
end (bm>
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我们可以直接写成 Dp['U
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /'oo;e
2、收缩数据库 9ad`q+kY
--重建索引 xkf2;
DBCC REINDEX f)vnm*&-
DBCC INDEXDEFRAG xS,F
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--收缩数据和日志 B\D)21Ik}%
DBCC SHRINKDB XK~HfA?
DBCC SHRINKFILE -sHX
3、压缩数据库 _"*vj-{-y
dbcc shrinkdatabase(dbname) ~_BjcY
4、转移数据库给新用户以已存在用户权限 ?uCL[
exec sp_change_users_login 'update_one','newname','oldname' fFEB#l!oUb
go &CRgi488b
5、检查备份集 o0AT&<K
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +M.BMS2A<l
6、修复数据库 AclK9+V
ALTER DATABASE [dvbbs] SET SINGLE_USER e R[B0;c
GO N/>:})dav
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ~!ei]UP
GO "wH(tk4
ALTER DATABASE [dvbbs] SET MULTI_USER b~ )@e9
GO "}
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7、日志清除 WBKf)A^S
SET NOCOUNT ON YuuTLX%3
DECLARE @LogicalFileName sysname, ^coCsV^CW"
@MaxMinutes INT, (Jb#'(~a
@NewSize INT +Zi+
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USE tablename -- 要操作的数据库名 )Q9Qo)D T
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 = y^5PjN
@MaxMinutes = 10, -- Limit on time allowed to wrap log. o(}%b8 K
@NewSize = 1 -- 你想设定的日志文件的大小(M) C D6N8n]
-- Setup / initialize kjQW9QJ<
DECLARE @OriginalSize int &qY]W=9uK
SELECT @OriginalSize = size F<h+d917
FROM sysfiles (k+*0.T&?
WHERE name = @LogicalFileName 1q=Q/L4P
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _{): w~zi
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + "+2Cs
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ,e|"p[z~T
FROM sysfiles 7oZ Pb
WHERE name = @LogicalFileName z\FBN=54z
CREATE TABLE DummyTrans 4'3;{k$z
(DummyColumn char (8000) not null) {1=|H$wKg
DECLARE @Counter INT, %4`
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@StartTime DATETIME, AP z"k?D0
@TruncLog VARCHAR(255) 1tO96t^d%
SELECT @StartTime = GETDATE(), v?8i;[
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' PcbhylKd
DBCC SHRINKFILE (@LogicalFileName, @NewSize) /\Cf*cJ
EXEC (@TruncLog) jD<xpD
-- Wrap the log if necessary. .dYv.[?hL
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 5{W Aw !
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) erv94acq
AND (@OriginalSize * 8 /1024) > @NewSize hrJ(] [8
BEGIN -- Outer loop. Yt =)=n
SELECT @Counter = 0 t<c7%i#Od
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ObZhQ.&
BEGIN -- update RFsUb:%V7-
INSERT DummyTrans VALUES ('Fill Log') q'trd};xR
DELETE DummyTrans L!Tvz(_7f6
SELECT @Counter = @Counter + 1 8wO4;
END vr"Pr4z4i
EXEC (@TruncLog) k:7Gb7\
END vx7=I\1
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ic}TiTK
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + BT}l"
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' a
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FROM sysfiles o%-KO? YW
WHERE name = @LogicalFileName S;t`C~l\
DROP TABLE DummyTrans Y>C05?>
SET NOCOUNT OFF \^pc"?Rc
8、说明:更改某个表 dYOY8r/
exec sp_changeobjectowner 'tablename','dbo' Mb"y{Fox
9、存储更改全部表 k8J zey]X
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @x*xgf
@OldOwner as NVARCHAR(128), {m3#1iV9
@NewOwner as NVARCHAR(128) Y6Y"fb%K
AS C(h<s
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DECLARE @Name as NVARCHAR(128) n>,GmCo
DECLARE @Owner as NVARCHAR(128) TH y?Y
DECLARE @OwnerName as NVARCHAR(128) r"K!]Vw
DECLARE curObject CURSOR FOR DC_uh
select 'Name' = name, `e;r$Vpd_
'Owner' = user_name(uid) 2::YR?
from sysobjects +qpG$#J0
where user_name(uid)=@OldOwner ,K@[+ R!
order by name LRWM}'.s
OPEN curObject [X /s^42
FETCH NEXT FROM curObject INTO @Name, @Owner z3 ^_C`(F
WHILE(@@FETCH_STATUS=0) 'aV'Am+:
BEGIN -B/'ArOo]
if @Owner=@OldOwner ^kC!a>&
begin .>r3ZwrE'
set @OwnerName = @OldOwner + '.' + rtrim(@Name) `#<UsU,~Lu
exec sp_changeobjectowner @OwnerName, @NewOwner |RD)pvVM
end R#YeE`K
-- select @name,@NewOwner,@OldOwner zICCSF&H
FETCH NEXT FROM curObject INTO @Name, @Owner %MGt3)
END 2[=3-1c
close curObject wjH1Ombt
deallocate curObject fUCjC*#1
GO Odw'Ua
10、SQL SERVER中直接循环写入数据 Wj!+
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declare @i int *pD|N
set @i=1 F#L1~\7
while @i<30 %2b^t*CQ
begin )l!
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insert into test (userid) values(@i) 1_!?wMo:f
set @i=@i+1 :_xfi9L~W0
end 7f
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小记存储过程中经常用到的本周,本月,本年函数 m rsmul{
Dateadd(wk,datediff(wk,0,getdate()),-1) }pf|GdL
Dateadd(wk,datediff(wk,0,getdate()),6) pl[@U<8aw
Dateadd(mm,datediff(mm,0,getdate()),0) F
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 31 <0Nw;l
Dateadd(yy,datediff(yy,0,getdate()),0) Y+),c14#
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) lw~
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上面的SQL代码只是一个时间段 Xm|~1 k_3
Dateadd(wk,datediff(wk,0,getdate()),-1) ){)-}M
Dateadd(wk,datediff(wk,0,getdate()),6) =Yl ea,S
就是表示本周时间段. dR_6j}
下面的SQL的条件部分,就是查询时间段在本周范围内的: (_@]-
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) cK\
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而在存储过程中 |,=^P`#%
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ~Gh7i>n*
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1anh@T.