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。 DwIX\9
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一、基础 Qw.j
1、说明:创建数据库 uolEX+
CREATE DATABASE database-name AZfW
2、说明:删除数据库 />dYk Iv
drop database dbname xnPi'?A]
3、说明:备份sql server W6jdS;3
--- 创建 备份数据的 device -P We
USE master ,m1F<Pdts
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' M6H#Y2!ZbC
--- 开始 备份 []hC*
BACKUP DATABASE pubs TO testBack Y(6 p&I
4、说明:创建新表 9K4Jg]?
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) QN^AihsPi
根据已有的表创建新表: x?RYt4 S
A:create table tab_new like tab_old (使用旧表创建新表) O9R[F
B:create table tab_new as select col1,col2... from tab_old definition only X*e<g=
5、说明:删除新表 ;0-Y),
drop table tabname e<r}{=1w
6、说明:增加一个列 dr]Pns9
Alter table tabname add column col type hYSf;cG}A
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+
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7、说明:添加主键: Alter table tabname add primary key(col) st wxF?\NS
说明:删除主键: Alter table tabname drop primary key(col) 1hW"#>f7
8、说明:创建索引:create [unique] index idxname on tabname(col....) M7\yEi"*
删除索引:drop index idxname E[2xo/H
注:索引是不可更改的,想更改必须删除重新建。 l G $s(
9、说明:创建视图:create view viewname as select statement @q+X:K5b
删除视图:drop view viewname 1[ 40\ sM
10、说明:几个简单的基本的sql语句 PEPf=sm
选择:select * from table1 where 范围 LuvRxmQ`
插入:insert into table1(field1,field2) values(value1,value2) ';3#t(J;
删除:delete from table1 where 范围 E{xcu9
更新:update table1 set field1=value1 where 范围 UpS7>c7s
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! zaG1
排序:select * from table1 order by field1,field2 [desc] s|IC;C|
总数:select count as totalcount from table1 6Ej.X)~'K
求和:select sum(field1) as sumvalue from table1 2dnyIgi
平均:select avg(field1) as avgvalue from table1 3h`_Qv%g
最大:select max(field1) as maxvalue from table1 F-PQ`@ZNW
最小:select min(field1) as minvalue from table1 H1-eMDe
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11、说明:几个高级查询运算词 @3Gr2/a
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A: UNION 运算符 T1i}D"H %
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。 ?XB[awTD~
B: EXCEPT 运算符 oe,yCdPs
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。 Qz`v0"'w
C: INTERSECT 运算符 9z kRwrQ
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。 Cnv?0to2l
注:使用运算词的几个查询结果行必须是一致的。 ~zhP[qA})
12、说明:使用外连接
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A、left outer join: 3NSX(gC%
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。 !z2 KQ
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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 ~TYpq;rq
B:right outer join: _m*FHi
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。 4~~G
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C:full outer join: EGxCNB
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。 >b2wFo/em
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二、提升 u#nM_UJe
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) GBYwS{4
法一:select * into b from a where 1<>1 :N64FR#
法二:select top 0 * into b from a SGP)A(,k9
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) $LW8 vo7
insert into b(a, b, c) select d,e,f from b; V,&A?
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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) GD0Q`gWNe
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Cq[<CPAS
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Zmz $
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4、说明:子查询(表名1:a 表名2:b) *;[g Ga~
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) nd~O*-uYg
5、说明:显示文章、提交人和最后回复时间 6h?)x
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b X=jHH=</
6、说明:外连接查询(表名1:a 表名2:b) {ep.So6
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Kp>fOe'KW
7、说明:在线视图查询(表名1:a ) }~Ir&
select * from (SELECT a,b,c FROM a) T where t.a > 1; 8 `}I]
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 K)W:@,*
select * from table1 where time between time1 and time2 ffR<G&"n~b
select a,b,c, from table1 where a not between 数值1 and 数值2 e#!p6+#"
9、说明:in 的使用方法 +g&M@8XO&
select * from table1 where a [not] in ('值1','值2','值4','值6') _K3;$2d|R
10、说明:两张关联表,删除主表中已经在副表中没有的信息 RC!9@H5S#
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5Kl;(0B9
11、说明:四表联查问题: ''H;/&nDX
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... D[dI_|59a
12、说明:日程安排提前五分钟提醒 <Yn-sH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,j(S'Pw
13、说明:一条sql 语句搞定数据库分页 7V-uQ)*
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 tHV+#3h
14、说明:前10条记录 `]F#j ]"
select top 10 * form table1 where 范围 RMlx[nsq
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) q9(Z9$a(\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) h-6x! 6pm
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 8*^*iEsR
(select a from tableA ) except (select a from tableB) except (select a from tableC) upiYo(sN.
17、说明:随机取出10条数据 AI]lG]q8
select top 10 * from tablename order by newid() $l_\9J913
18、说明:随机选择记录 RG:_:%@%}
select newid() ~p
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19、说明:删除重复记录 K"8!
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 10CRgrZ
20、说明:列出数据库里所有的表名 ~z'Y(qG
select name from sysobjects where type='U' w%$J<Z^-?
21、说明:列出表里的所有的 dg#w!etB
select name from syscolumns where id=object_id('TableName') ~cSE 9ul
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。 <=%=,Yk
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 :kvQ3E0
显示结果: .V@3zzv\
type vender pcs yM*_"z!L
电脑 A 1 QBjvbWoIG(
电脑 A 1 ~:99
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光盘 B 2 vf-8DB
光盘 A 2 {Rq5=/b
手机 B 3 Z6#(83G4
手机 C 3 |eqp3@Y1E
23、说明:初始化表table1 KebC$g@W
TRUNCATE TABLE table1 as"@E>a
24、说明:选择从10到15的记录 +iw4>0pi
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc \hP.Q;"MtO
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三、技巧 Z GrDa
1、1=1,1=2的使用,在SQL语句组合时用的较多 uP.dCs9-
"where 1=1" 是表示选择全部 "where 1=2"全部不选, aX?
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如: a~Yq0 d?`D
if @strWhere !='' Lc0=5]D
begin bT`et*]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere T3PwM2em_`
end WQsu}_g5y
else Y?:"nhN
begin jXIVR'n(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' r |2{(+
end o@ @| 4
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我们可以直接写成 T}Wse{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere /]2I%Q
2、收缩数据库 fa!8+kfi
--重建索引 &3:<WU:U
DBCC REINDEX V^_U=Ed@M
DBCC INDEXDEFRAG zA|)9Dq
--收缩数据和日志 dte-2?%~j
DBCC SHRINKDB 3\K;y>NK
DBCC SHRINKFILE &.JJhX
3、压缩数据库
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dbcc shrinkdatabase(dbname) oiQ:&$y
4、转移数据库给新用户以已存在用户权限 sU/vXweky"
exec sp_change_users_login 'update_one','newname','oldname' 7,Y+FZ
go fYlqaO4[
5、检查备份集 De<i
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' o0TB>DX$`
6、修复数据库 rLA^ &P:
ALTER DATABASE [dvbbs] SET SINGLE_USER x M{SFF
GO `:Zgq+j&
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK U "v=XK)!
GO v.c.5@%%o
ALTER DATABASE [dvbbs] SET MULTI_USER #v*3-) 8
GO 4)Ew
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7、日志清除 l7U<]i GL
SET NOCOUNT ON tg7QX/KX
DECLARE @LogicalFileName sysname, ol}}c6
@MaxMinutes INT, A@e!~
@NewSize INT yUs/lI, Q
USE tablename -- 要操作的数据库名 ]PB95%
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 r|y\FL
@MaxMinutes = 10, -- Limit on time allowed to wrap log. q><wzCnRu~
@NewSize = 1 -- 你想设定的日志文件的大小(M) L;fz7?_j
-- Setup / initialize P>R u
DECLARE @OriginalSize int YD#L@:&gv
SELECT @OriginalSize = size bVr`a*EM
FROM sysfiles {"O-/*
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WHERE name = @LogicalFileName V-18~+F~"a
SELECT 'Original Size of ' + db_name() + ' LOG is ' + eh,_g.
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + .e\PCf9v
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' f7Gs1{
FROM sysfiles 4@0Z<8Mo
WHERE name = @LogicalFileName B[5<&
CREATE TABLE DummyTrans 6iY(RYZ7-
(DummyColumn char (8000) not null) m?=J;r"Re
DECLARE @Counter INT, 0>
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@StartTime DATETIME, [-^xw1:
@TruncLog VARCHAR(255) 8v6AfTo%
SELECT @StartTime = GETDATE(), p{&o{+c
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <2wC)l3j*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \b#`Ahf`
EXEC (@TruncLog) DH uUEv<
-- Wrap the log if necessary. Ym2Ac>I4
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired T*k}E
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) TXqtE("BDl
AND (@OriginalSize * 8 /1024) > @NewSize eTI?Mu>C
BEGIN -- Outer loop. ycf)*0k
SELECT @Counter = 0 i0~Af`v
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) NKiWt
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BEGIN -- update
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INSERT DummyTrans VALUES ('Fill Log') 3S
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DELETE DummyTrans o'? WWJK6w
SELECT @Counter = @Counter + 1 I(j$^DA.
END VdGpreRPC
EXEC (@TruncLog) hb1eEn
END $Qxy@vU
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :g{ybTSEe
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + .&n!4F'
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [{zfI`6
FROM sysfiles .u]d5z
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WHERE name = @LogicalFileName Rpj{!Ia
DROP TABLE DummyTrans 'ZAIe7i&
SET NOCOUNT OFF bd2QQ1[1vh
8、说明:更改某个表 &,* ILz
exec sp_changeobjectowner 'tablename','dbo' 9}+X#ma.Nc
9、存储更改全部表 /)sP<WPQ6
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch I~nz~U:ak
@OldOwner as NVARCHAR(128), DeI3(o7
@NewOwner as NVARCHAR(128) YR[I,j
AS z}Um$'. =
DECLARE @Name as NVARCHAR(128) BN6cu9a
DECLARE @Owner as NVARCHAR(128) [EK@f,iM
DECLARE @OwnerName as NVARCHAR(128) csV3mzP
DECLARE curObject CURSOR FOR r(rT.D&
select 'Name' = name, z&\N^tBv
'Owner' = user_name(uid) T/:6Z
from sysobjects m=a^t
where user_name(uid)=@OldOwner %eGI]!vf
order by name Bve',.xH
OPEN curObject }/Qj8l.
FETCH NEXT FROM curObject INTO @Name, @Owner KGmAnN
WHILE(@@FETCH_STATUS=0) u"8KH
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BEGIN V5gr-^E
if @Owner=@OldOwner IuMJ-"
begin @h(Z;
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &AVX03P
exec sp_changeobjectowner @OwnerName, @NewOwner FytGg[#]
end iu2O/l#r
-- select @name,@NewOwner,@OldOwner j|{
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FETCH NEXT FROM curObject INTO @Name, @Owner 0qm CIcg
END $"va8,
close curObject 6q,CEm
deallocate curObject Ao@WTs9
GO 7cO1(yE#vr
10、SQL SERVER中直接循环写入数据 /v.<h*hxWy
declare @i int +jO#?J
set @i=1 )~IOsTjI
while @i<30 ft~QVe!
begin EAE#AB-A
insert into test (userid) values(@i) u/xP$
set @i=@i+1 L]l?_#*x
end C8=r sh
小记存储过程中经常用到的本周,本月,本年函数 4\j1+&W
Dateadd(wk,datediff(wk,0,getdate()),-1) 7^1K4%IPl
Dateadd(wk,datediff(wk,0,getdate()),6) tg<bVA)E'J
Dateadd(mm,datediff(mm,0,getdate()),0) SZ:R~4 A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) |W*2L]&
Dateadd(yy,datediff(yy,0,getdate()),0) ]hRs -x
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) {MUO25s02
上面的SQL代码只是一个时间段 JURg=r]LI
Dateadd(wk,datediff(wk,0,getdate()),-1) .=) *Qx+
Dateadd(wk,datediff(wk,0,getdate()),6) ygd*zy9
就是表示本周时间段. -s^cy+jd
下面的SQL的条件部分,就是查询时间段在本周范围内的: Nh !U
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) .(s@{=
而在存储过程中 oG-Eac,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) +e#(p<
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 2} _^~8