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。 EjY8g@M;t
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一、基础 ;zF3e&e(
1、说明:创建数据库 VAD9mS^~
CREATE DATABASE database-name |!Ryl}Oi
2、说明:删除数据库 Hs6?4cgj
drop database dbname E@}
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3、说明:备份sql server YmwUl> @{
--- 创建 备份数据的 device
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USE master 'DeI]IeP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' [}ayaXXQ5
--- 开始 备份 !{S& "
BACKUP DATABASE pubs TO testBack h&|PHI
4、说明:创建新表 Mn>/\e
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) a%g |E'\Jw
根据已有的表创建新表: O-uno{Fd*
A:create table tab_new like tab_old (使用旧表创建新表) (g HCu
B:create table tab_new as select col1,col2... from tab_old definition only ^osXM`
5、说明:删除新表 $:l>g)c
drop table tabname A.YXK%A%
6、说明:增加一个列 E&z`BPd
Alter table tabname add column col type Vf*Z }'
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 or<n[<D-C
7、说明:添加主键: Alter table tabname add primary key(col) iY[+BI:
说明:删除主键: Alter table tabname drop primary key(col) 3bU(ea^e$
8、说明:创建索引:create [unique] index idxname on tabname(col....) Bz+zEXBC
删除索引:drop index idxname R"2wop
注:索引是不可更改的,想更改必须删除重新建。 U\'HB.P\
9、说明:创建视图:create view viewname as select statement
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删除视图:drop view viewname nY)H-u^
10、说明:几个简单的基本的sql语句 7$zeRYD+
选择:select * from table1 where 范围 ; <NK
插入:insert into table1(field1,field2) values(value1,value2) ~vPR9\e
删除:delete from table1 where 范围 .D8|_B
更新:update table1 set field1=value1 where 范围 Tf*DFyr
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4AWL::FU5
排序:select * from table1 order by field1,field2 [desc] y3+iADo.p
总数:select count as totalcount from table1 D\H;_k8
求和:select sum(field1) as sumvalue from table1 gfr+`4H >v
平均:select avg(field1) as avgvalue from table1 (/ qOY
最大:select max(field1) as maxvalue from table1 x$L(!ZDh
最小:select min(field1) as minvalue from table1 2j =i\ B
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11、说明:几个高级查询运算词 `m")v0n3
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A: UNION 运算符 `qs[a}%'>"
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。 oE.59dx
B: EXCEPT 运算符 a #`Y(R'
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。 '_~qAx@F#c
C: INTERSECT 运算符 "h`oT4j5q
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。 Kj{(jT
注:使用运算词的几个查询结果行必须是一致的。 Hy~+|hLvh
12、说明:使用外连接 Rt+ak}
A、left outer join: 8\BGL
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。 @{q:179w^
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 cF V[k'F
B:right outer join: CqVeR';2
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。 WcHL:38
C:full outer join: y>! 8mDvZ
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。 nl)l:A+q8
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二、提升 fMm.V=/+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) =pk5'hBAi
法一:select * into b from a where 1<>1 p6c&vEsNj
法二:select top 0 * into b from a 1DRih>+#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) kMx^L;:n
insert into b(a, b, c) select d,e,f from b; @>Bgld&vl
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) dTrz7ayH
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 [,0[\NC
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Kl/n>qEt
4、说明:子查询(表名1:a 表名2:b) UbDpSfub
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) -]. a0
5、说明:显示文章、提交人和最后回复时间 Dbg,|UH
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b V'^E'[Dd{
6、说明:外连接查询(表名1:a 表名2:b) /UG]hJ-wn
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c vrq5 +K&||
7、说明:在线视图查询(表名1:a ) +l27y0>t
select * from (SELECT a,b,c FROM a) T where t.a > 1; vq` M]1]FO
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 +(U;+6 b
select * from table1 where time between time1 and time2 csjCXT=Ve
select a,b,c, from table1 where a not between 数值1 and 数值2 ,CxIA^
9、说明:in 的使用方法 8= "01
select * from table1 where a [not] in ('值1','值2','值4','值6') ^JMO POm
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7R7e3p,K
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 6>NK2} `
11、说明:四表联查问题: ){I!orQ
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 ..... "$#<+H>O
12、说明:日程安排提前五分钟提醒 A4{p(MS5
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 91\Sb:>
13、说明:一条sql 语句搞定数据库分页 oJ.5! Kg
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 +mRc8 G
14、说明:前10条记录 Wl0p-h
select top 10 * form table1 where 范围 mJ>msI
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) /T<))@$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) hA=}R.gi
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 J3QL%#
(select a from tableA ) except (select a from tableB) except (select a from tableC) i4}+n^oSYo
17、说明:随机取出10条数据 2|A?9aE%0
select top 10 * from tablename order by newid() k?;@5r) y-
18、说明:随机选择记录 M(U<H;Csk
select newid() 4DgH/Yo
19、说明:删除重复记录 ]o?r(1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) f=hT
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20、说明:列出数据库里所有的表名 VOSq%hB
select name from sysobjects where type='U' z 4qEC
21、说明:列出表里的所有的 _;mA(j
select name from syscolumns where id=object_id('TableName') F*-+5nJ&@
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。 b6NGhkr'\
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 _$KEE|9
显示结果: ,4HZ-|EOZ
type vender pcs puAjAvIax
电脑 A 1 Oq*;GR(Q
电脑 A 1 Oy_%U*
光盘 B 2 | Di7,$c
光盘 A 2 y>>)Yo&|
手机 B 3 A5E^1j}h@
手机 C 3 P%aNbMg
23、说明:初始化表table1 ?*^HZ~O1
TRUNCATE TABLE table1 37b6w6{D
24、说明:选择从10到15的记录 5t,X;
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc i`}!<{k
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三、技巧 _BoYyJQH
1、1=1,1=2的使用,在SQL语句组合时用的较多 muMd9\p
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0TaN#
如: N
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if @strWhere !='' `ES+$ O>
begin \h/)un5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere WP{U9YF2
end &NX7
else Qp9QSyMs}
begin 8Z CR9%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @E4ya$A)F
end z.Vf,<H
我们可以直接写成 . @0@Y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9-Z?
2、收缩数据库 7Ue&y8Yf
--重建索引 w7c0jIf{
DBCC REINDEX 26}fB
DBCC INDEXDEFRAG y~'%PUN
--收缩数据和日志 >8|V[-H
DBCC SHRINKDB ZypK''&oc
DBCC SHRINKFILE \M;cF"e-S
3、压缩数据库 E/<n"'0ek
dbcc shrinkdatabase(dbname) O^n\lik
4、转移数据库给新用户以已存在用户权限 G-|
exec sp_change_users_login 'update_one','newname','oldname' 67Ev$a_d"
go D?FmlDTr[
5、检查备份集 cTQ._|M
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ITy/h]0
6、修复数据库 CfT(a!;Eox
ALTER DATABASE [dvbbs] SET SINGLE_USER zY2x_}#Q\"
GO j;I(w [@P
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK fohZ&f|>
GO nlZJ}xZ
ALTER DATABASE [dvbbs] SET MULTI_USER P%;lHC #i
GO \5-Dp9vG
7、日志清除 L}7 TM:%
SET NOCOUNT ON U|<>xe*|%
DECLARE @LogicalFileName sysname, }`aT=_ B
@MaxMinutes INT, LLL;SNY
@NewSize INT Zrzv';
USE tablename -- 要操作的数据库名 ?<rZ9$
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 T$sm}=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. biZ=TI2P,L
@NewSize = 1 -- 你想设定的日志文件的大小(M) H43d[@h
-- Setup / initialize Z<*"sFpAO
DECLARE @OriginalSize int /9,y+"0SQz
SELECT @OriginalSize = size ,/qY 9eh
FROM sysfiles J!}\v=Rn
WHERE name = @LogicalFileName 2UIZ<#|D>s
SELECT 'Original Size of ' + db_name() + ' LOG is ' + fWf't2H&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \]g51U!'
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +6x}yc:yd
FROM sysfiles +,Or^pO=
WHERE name = @LogicalFileName _gEojuaN
CREATE TABLE DummyTrans _U9.u#>sV
(DummyColumn char (8000) not null) Z_a@,k:+[
DECLARE @Counter INT, /A+5q\8G
@StartTime DATETIME, /Ny#+$cfk
@TruncLog VARCHAR(255) hj\A-Yf
SELECT @StartTime = GETDATE(), bYmk5fpRG
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' pgs<Mo$\%B
DBCC SHRINKFILE (@LogicalFileName, @NewSize) T7-yZSw-m
EXEC (@TruncLog) @yj~5Gf(j
-- Wrap the log if necessary. SW5n?Qj3-
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired >[&ser
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p(cnSvg
AND (@OriginalSize * 8 /1024) > @NewSize [dXa,
BEGIN -- Outer loop. BY9Z}/{j
SELECT @Counter = 0 D< kf/hj
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ?M^qSo=/~
BEGIN -- update 3.9/mztS
INSERT DummyTrans VALUES ('Fill Log') ~Kl"V%>
DELETE DummyTrans lbGPy'h<rt
SELECT @Counter = @Counter + 1 h/2@4XKj
END eFotV.T!#
EXEC (@TruncLog) F&lH5
END @NL37C
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 1!yd(p=cL
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + xLms|jS
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Xpv<v[a
FROM sysfiles j\NCoos
WHERE name = @LogicalFileName B)/c]"@89
DROP TABLE DummyTrans C^c<s
SET NOCOUNT OFF S<jiy<|`
8、说明:更改某个表 Hy -)yR
exec sp_changeobjectowner 'tablename','dbo' {c~w
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9、存储更改全部表 _~'MQ`P
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch H?FiZy*[Y
@OldOwner as NVARCHAR(128), s8 u`v1
@NewOwner as NVARCHAR(128) tvBLfqIr
AS =*{7G*tS
DECLARE @Name as NVARCHAR(128) |
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DECLARE @Owner as NVARCHAR(128) s8'!1rHd
DECLARE @OwnerName as NVARCHAR(128) R;fe v
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DECLARE curObject CURSOR FOR WYP\J1sy
select 'Name' = name, k!G{#(++&6
'Owner' = user_name(uid) eA{A3.f"Hz
from sysobjects 72/ bC
where user_name(uid)=@OldOwner -8vGvI>
order by name Y;iI=U
OPEN curObject ]
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FETCH NEXT FROM curObject INTO @Name, @Owner B.KK@
WHILE(@@FETCH_STATUS=0) 4>2\{0r
BEGIN O9m sPb:
if @Owner=@OldOwner zo("v*d*q
begin #DARZh U)
set @OwnerName = @OldOwner + '.' + rtrim(@Name) m%UF{I,
exec sp_changeobjectowner @OwnerName, @NewOwner ^6Zx-Mf\
end wp'[AR}
-- select @name,@NewOwner,@OldOwner lHPnAaue@
FETCH NEXT FROM curObject INTO @Name, @Owner yE.st9m
END nf[KD,f
close curObject gI9nxy
deallocate curObject 8k)*f+1o
GO ,1cpV|mAr
10、SQL SERVER中直接循环写入数据 s];0-65)
declare @i int _00}O+GLM4
set @i=1 [mNu m3e
while @i<30 !vVW8hbp
begin IWm@pfC+g
insert into test (userid) values(@i) CIsX$W
set @i=@i+1 =[[I<[BZq
end \}%_FnP0ZU
小记存储过程中经常用到的本周,本月,本年函数 I2pE}6q
Dateadd(wk,datediff(wk,0,getdate()),-1) LE~vSm^#
Dateadd(wk,datediff(wk,0,getdate()),6) J`C 2}$
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Dateadd(mm,datediff(mm,0,getdate()),0) Q@8(e&{#W
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) +>AVxV=A#
Dateadd(yy,datediff(yy,0,getdate()),0) ic3Szd^4
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2}bXX'Y
上面的SQL代码只是一个时间段 S6\E
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Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) .r&CIL>
就是表示本周时间段. 9V~hz (^
下面的SQL的条件部分,就是查询时间段在本周范围内的: 65VTKlDD
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) OoRg:"9{#
而在存储过程中 q&O9W?E8dG
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) !)CY\c4}d>
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) B5h)F> &G