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。 ,;EIh}
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一、基础 &PR5q7
1、说明:创建数据库 ^h(ew1:
CREATE DATABASE database-name k0OYJ/
2、说明:删除数据库 =:xW>@bh|
drop database dbname u4t7Ie*Q
3、说明:备份sql server rMdt:`
--- 创建 备份数据的 device &p'Y^zL-
USE master %R}qg6dL
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' B{QBzx1L9c
--- 开始 备份 %^?fMeI|Y
BACKUP DATABASE pubs TO testBack 5dx$HE&b)
4、说明:创建新表 E(*0jAvO[z
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) QE^$=\l0
根据已有的表创建新表: 5#HW2"7
A:create table tab_new like tab_old (使用旧表创建新表) 7BE>RE=)
B:create table tab_new as select col1,col2... from tab_old definition only ]&o$b ]
5、说明:删除新表 UE8kpa)cQ
drop table tabname ..IfP@
6、说明:增加一个列 ahJ`T*)HY
Alter table tabname add column col type M,j U}yD3
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ~uj#4>3T
7、说明:添加主键: Alter table tabname add primary key(col) @3>u@
说明:删除主键: Alter table tabname drop primary key(col) ;@mS^ik")$
8、说明:创建索引:create [unique] index idxname on tabname(col....) w^\52
删除索引:drop index idxname S8kCp;
注:索引是不可更改的,想更改必须删除重新建。 Xc =Y
9、说明:创建视图:create view viewname as select statement AiwOc+R
删除视图:drop view viewname ^%d\qd`
10、说明:几个简单的基本的sql语句 [zH:1Zhl&
选择:select * from table1 where 范围 R"-mKT}
插入:insert into table1(field1,field2) values(value1,value2) RFi
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删除:delete from table1 where 范围 ?qmRbDI
更新:update table1 set field1=value1 where 范围 =J18eH!]
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 6gL#C&
排序:select * from table1 order by field1,field2 [desc] h\$$JeSV]
总数:select count as totalcount from table1 MR;1
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求和:select sum(field1) as sumvalue from table1 oK9( /v
平均:select avg(field1) as avgvalue from table1 TtJH7
最大:select max(field1) as maxvalue from table1 (9tX5$e6N
最小:select min(field1) as minvalue from table1 h&M{]E9=
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11、说明:几个高级查询运算词 TtK[nP
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A: UNION 运算符 )~GmU9f
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。 ]P9l jwR
B: EXCEPT 运算符 ]RZ|u*l=x
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。 ]vz%iv_
C: INTERSECT 运算符 %2}-2}[>
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。 ](Xb_xMf
注:使用运算词的几个查询结果行必须是一致的。 >,v`EIg
12、说明:使用外连接 pf]xqhL
A、left outer join: 272q1~&
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。 [xK3F+
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 MOQ6:
B:right outer join: <kfnpB=
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。 C+*d8_L
C:full outer join: Yc`o5Q\>
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。 "x#-sZ=
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二、提升 JOj;^h
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) $6#CqWhI
法一:select * into b from a where 1<>1 ,j#XOy`mzy
法二:select top 0 * into b from a \J4L:.`qS
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) S:u:z=:r
insert into b(a, b, c) select d,e,f from b; mWv3!i;G<s
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) 9G9t" {
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 gK+4C
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. rExnxQ<e
4、说明:子查询(表名1:a 表名2:b) l.(v^3:X
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) _1!7V3|^
5、说明:显示文章、提交人和最后回复时间
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b fIM,lt
6、说明:外连接查询(表名1:a 表名2:b) OP;v bZ
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c $ux,9H'[
7、说明:在线视图查询(表名1:a ) 0!D4pvlt
select * from (SELECT a,b,c FROM a) T where t.a > 1; Vo4,@scG
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 :vYYfs&
select * from table1 where time between time1 and time2 -Sqz5lo
select a,b,c, from table1 where a not between 数值1 and 数值2 >R|/M`<ph
9、说明:in 的使用方法 %3s1z<;R[S
select * from table1 where a [not] in ('值1','值2','值4','值6') dR
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 +<'Ev~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) # ' =a=8-$
11、说明:四表联查问题: ?K1/ <PE+
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 ..... PG2: ~$L0
12、说明:日程安排提前五分钟提醒 ]GUvV&6@(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 n#mA/H;wV
13、说明:一条sql 语句搞定数据库分页 &g#@3e1>
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 <:_wbVn-
14、说明:前10条记录 _qU4Fadgm
select top 10 * form table1 where 范围 i)\L:qF5
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) "RedK '7g
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) YP
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 c7 ?_46J
(select a from tableA ) except (select a from tableB) except (select a from tableC) __uA}fZp
17、说明:随机取出10条数据 SfA\}@3
select top 10 * from tablename order by newid() AWcLUe {
18、说明:随机选择记录 }#3V+X
select newid() '|ad_M
19、说明:删除重复记录 {vs
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
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20、说明:列出数据库里所有的表名 z Eq GD2"
select name from sysobjects where type='U' eJ,/:=QQ{
21、说明:列出表里的所有的 ~W*FCG#E
select name from syscolumns where id=object_id('TableName') Cmu@4j&
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 `Nv=B1
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type v/@^Q1G/:
显示结果: 4Xgg%@C
type vender pcs 0Vj4+2?L5;
电脑 A 1 o\BOL3H
电脑 A 1 [v7F1@6b
光盘 B 2 16w|O|^<
光盘 A 2 s:?SF.
手机 B 3 YD<:,|H
手机 C 3 ?U%QG5/>
23、说明:初始化表table1 S
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TRUNCATE TABLE table1 i3dkYevs?
24、说明:选择从10到15的记录 F7A=GF'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^"2i
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三、技巧 au N6prGe
1、1=1,1=2的使用,在SQL语句组合时用的较多 u$h
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, r~E=4oB7
如: \?w2a$?6w
if @strWhere !='' %]Fd[pzF
begin NYt&@Z}]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ?TM,Q
end Ua<5U5
else nR7d4)
begin j -0z5|*KE
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "76]u)
end T m,b,hi$
我们可以直接写成 ^b/ Z)3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |_LU~ 7./
2、收缩数据库
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--重建索引 wZG\>9~
DBCC REINDEX &?W0mW(
DBCC INDEXDEFRAG BYpG
--收缩数据和日志 D~biKrg?=
DBCC SHRINKDB *Tas`WA
DBCC SHRINKFILE 4^:\0UF
3、压缩数据库 ~F7-HaQJ
dbcc shrinkdatabase(dbname) R_(tjkT
4、转移数据库给新用户以已存在用户权限 1=t>HQ
exec sp_change_users_login 'update_one','newname','oldname' U [*FCD!~
go u_hD}V^x4
5、检查备份集 4h~iPn'Wl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 5G::wuxk
6、修复数据库 VkvB<3
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO 0x'#_G65y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK /rMI"khB
GO >,TUZ
ALTER DATABASE [dvbbs] SET MULTI_USER 34z"Pm
GO R,gR;Aarw
7、日志清除 t|a2;aq_
SET NOCOUNT ON ^]7}YF2|
DECLARE @LogicalFileName sysname, 'w!Cn>
@MaxMinutes INT, OSlvwH%(EE
@NewSize INT JX-'
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USE tablename -- 要操作的数据库名 AB=daie
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 #EO9UW5
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }0eF~>Df
@NewSize = 1 -- 你想设定的日志文件的大小(M) oT^{b\XN
-- Setup / initialize Jzj1w}?H
DECLARE @OriginalSize int q'|rgT
SELECT @OriginalSize = size ?
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FROM sysfiles G.rrv
WHERE name = @LogicalFileName |*:'TKzNS
SELECT 'Original Size of ' + db_name() + ' LOG is ' + o4j[p3$
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + %{ABaeb]
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' IT(lF
FROM sysfiles Q
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WHERE name = @LogicalFileName >{N9kWY
CREATE TABLE DummyTrans Z8zmHc"IH
(DummyColumn char (8000) not null) aIJt0;
DECLARE @Counter INT, s8wmCzB~
@StartTime DATETIME, W=vG$
@TruncLog VARCHAR(255) j:5=s%S
SELECT @StartTime = GETDATE(), vu|n<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' HIQ_%L4]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) H(bs$C4F
EXEC (@TruncLog) plUZ"Tr
-- Wrap the log if necessary. -}=i 04^
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired aEM %R<e
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) t0o`-d(
AND (@OriginalSize * 8 /1024) > @NewSize HGXt
BEGIN -- Outer loop. #z&&M"*a|
SELECT @Counter = 0 n1JRDw"e$$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) o}W%I/s
BEGIN -- update {6"Ph(I1
INSERT DummyTrans VALUES ('Fill Log') &S( .GdEf
DELETE DummyTrans v\!Be[ ?
SELECT @Counter = @Counter + 1 Anscr
END !_`&Wks
EXEC (@TruncLog) M:-.o
END ,RJtm%w
SELECT 'Final Size of ' + db_name() + ' LOG is ' + T,]7ICF#
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Y,WuBH
FROM sysfiles %ZNI:Uh
WHERE name = @LogicalFileName ~p1j`r;
DROP TABLE DummyTrans iMI lZ
SET NOCOUNT OFF fIj|4a+
8、说明:更改某个表
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exec sp_changeobjectowner 'tablename','dbo' vY%d
9、存储更改全部表 N$h{Yvbn
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ]F; f`o
@OldOwner as NVARCHAR(128), ~V&aUDO>/
@NewOwner as NVARCHAR(128) vg
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AS w9NHk~LHKF
DECLARE @Name as NVARCHAR(128) KMU4n-s"o
DECLARE @Owner as NVARCHAR(128) eln&]d;
DECLARE @OwnerName as NVARCHAR(128)
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DECLARE curObject CURSOR FOR +VCGlr
select 'Name' = name, A3|Dz&@:
'Owner' = user_name(uid) X=hYB}}nu
from sysobjects VG,u7A*Z#
where user_name(uid)=@OldOwner J13>i7]L%
order by name !OBEM1~
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OPEN curObject >iD )eB
FETCH NEXT FROM curObject INTO @Name, @Owner _acE:H
WHILE(@@FETCH_STATUS=0) *8#i$w11M
BEGIN 1jy9lP=
if @Owner=@OldOwner l-ct?T_@
begin o(S{VGi,
set @OwnerName = @OldOwner + '.' + rtrim(@Name) P@,nA41,j
exec sp_changeobjectowner @OwnerName, @NewOwner Z\HX~*,6
end \hhmVt@@
-- select @name,@NewOwner,@OldOwner SQqD:{#g"
FETCH NEXT FROM curObject INTO @Name, @Owner GDD '[;
END Y7vA`kjD-C
close curObject %*&UJpbA
deallocate curObject J2j U4mR
GO Y=?yhAw
10、SQL SERVER中直接循环写入数据 cG?cUw).E
declare @i int 0#ClWynjRO
set @i=1 J41G&$j(
while @i<30 3:8{"md@2
begin Hd,p!_
insert into test (userid) values(@i) I_xXDr
set @i=@i+1 /Wy.>YC|
end b^p"|L
小记存储过程中经常用到的本周,本月,本年函数 mExVYp h
Dateadd(wk,datediff(wk,0,getdate()),-1) ^_ kJKM,
Dateadd(wk,datediff(wk,0,getdate()),6) #/I[Jqf
Dateadd(mm,datediff(mm,0,getdate()),0) Sr%;fq
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) BM(]QUxRd
Dateadd(yy,datediff(yy,0,getdate()),0) uPRQU+
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) i:u1s"3~
上面的SQL代码只是一个时间段 e0J6Ae4V[
Dateadd(wk,datediff(wk,0,getdate()),-1) -.T&(&>^
Dateadd(wk,datediff(wk,0,getdate()),6) S-YM%8A[
就是表示本周时间段. ed:@C?
下面的SQL的条件部分,就是查询时间段在本周范围内的: *P#WDXRwd
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 1P(|[W1
而在存储过程中 VMCLHpSfW
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) q+[SbG&
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) WdnIp!