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。 q"gqO%Wb|
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一、基础 ;{<aA 5
1、说明:创建数据库 q,[k7&HS
CREATE DATABASE database-name ?PBa'g
2、说明:删除数据库 ,HFs.9#&B
drop database dbname uh]"(h(>
3、说明:备份sql server z$JX'(<Z7
--- 创建 备份数据的 device +hE',i.
USE master bA}AD`5
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' {Ge+O<mD
--- 开始 备份 z]^+^c_
BACKUP DATABASE pubs TO testBack D
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4、说明:创建新表 96(R'^kNX
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) QBy{|sQ`
根据已有的表创建新表: R/^@cA
A:create table tab_new like tab_old (使用旧表创建新表) e]lJqC
B:create table tab_new as select col1,col2... from tab_old definition only '
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5、说明:删除新表 "-w^D!C
drop table tabname rRB~=J"
6、说明:增加一个列 \HAJ\9*w)
Alter table tabname add column col type sX+`wc
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 T4mv%zzS
7、说明:添加主键: Alter table tabname add primary key(col) J,f/fPaf7
说明:删除主键: Alter table tabname drop primary key(col) z{ptm7
8、说明:创建索引:create [unique] index idxname on tabname(col....) 7;&(}
删除索引:drop index idxname y|$R`P
注:索引是不可更改的,想更改必须删除重新建。 *)u?~r(F
9、说明:创建视图:create view viewname as select statement 5L8&/EN9-
删除视图:drop view viewname ^:`oP"%-T
10、说明:几个简单的基本的sql语句 sLb8*fak
选择:select * from table1 where 范围 cA D[3b[Gk
插入:insert into table1(field1,field2) values(value1,value2) N_ UQ
删除:delete from table1 where 范围 tAF]2VV(e
更新:update table1 set field1=value1 where 范围 \tY"BC4.
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! i+g~ Uj}h
排序:select * from table1 order by field1,field2 [desc] ,V,f2W 4
总数:select count as totalcount from table1 =I2@/,
求和:select sum(field1) as sumvalue from table1 4SgF,ac3r
平均:select avg(field1) as avgvalue from table1 ?w-1:NWjt
最大:select max(field1) as maxvalue from table1 I%oRvg|q
最小:select min(field1) as minvalue from table1 eP "`,<
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11、说明:几个高级查询运算词 |^R*4;Phe
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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。 -."kq.m*
B: EXCEPT 运算符 #ZJMlJ:q`"
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。 Vtr3G.P^
C: INTERSECT 运算符 Ly;I,)w
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。 i}v9ut]B
注:使用运算词的几个查询结果行必须是一致的。 W{
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12、说明:使用外连接 @}Zd (o
A、left outer join: Gqb])gXpl
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。 H+ lX-,
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 J!{Al
B:right outer join: mzX;s&N#
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。 'BY-OA#xJ
C:full outer join: ?~J i-{#X
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。 l<(cd,
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二、提升 H3, ut
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 8-m
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法一:select * into b from a where 1<>1 K/txD20
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法二:select top 0 * into b from a LXj5R99S
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8$0\J _
insert into b(a, b, c) select d,e,f from b; wJe?t$ac?
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) ,>n%
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 fiVHRSX60
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. .h4\{|
4、说明:子查询(表名1:a 表名2:b) 4*TmlY
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) &SH1q_&BQ
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 WF2NG;f=
6、说明:外连接查询(表名1:a 表名2:b) rAb&I"\ZY
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c MuwQZ]u
7、说明:在线视图查询(表名1:a ) Ha%F"V*
select * from (SELECT a,b,c FROM a) T where t.a > 1; d H?
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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 .Pe9_ZH$W
select * from table1 where time between time1 and time2 ZtK\HDdp
select a,b,c, from table1 where a not between 数值1 and 数值2 PY`L$e
9、说明:in 的使用方法 1svi8wh
select * from table1 where a [not] in ('值1','值2','值4','值6') y7:tr
10、说明:两张关联表,删除主表中已经在副表中没有的信息 \=;uu_v$
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Ye5jB2Z
11、说明:四表联查问题: w\Mnu}<e$
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 ..... ;#1Iiuh
12、说明:日程安排提前五分钟提醒 WkP
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 tu0aD%C
13、说明:一条sql 语句搞定数据库分页 \}5p0.=
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 d,0 }VaY=D
14、说明:前10条记录 a^t?vv
select top 10 * form table1 where 范围 H6K`\8/SeN
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.) m}3gZu]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) s
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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 KVPR}qTP;
(select a from tableA ) except (select a from tableB) except (select a from tableC) wJeG(h
17、说明:随机取出10条数据 2 rN ,D(
select top 10 * from tablename order by newid() xyA-P& N
18、说明:随机选择记录 /6KIl
select newid() l>6@:nq|R
19、说明:删除重复记录 x[(?#
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ,+`HQdq
20、说明:列出数据库里所有的表名 `y^sITr
select name from sysobjects where type='U' -F\qnsZ2
21、说明:列出表里的所有的 %0,-.(h
select name from syscolumns where id=object_id('TableName') 2-'Opu
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。 Wht(O~F
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 2;$k(x]
显示结果: FS"eM"z
type vender pcs wW 2d\Zd&
电脑 A 1 4/e60jA
电脑 A 1 ~+G#n"P n
光盘 B 2 P[ r];e
光盘 A 2 47r&8C+&\
手机 B 3 X^@I].
手机 C 3 17|np2~
23、说明:初始化表table1 pI.+"Hz
TRUNCATE TABLE table1 Sv'y e
24、说明:选择从10到15的记录 l"(6]Z 4
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc e`K)_>^n#
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三、技巧 _[K"gu
1、1=1,1=2的使用,在SQL语句组合时用的较多 DgHaOAdU
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 3;[DJ5
如: b:J(b?
if @strWhere !='' MZ>6o5K|
begin FLZWZ;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /9pM>Cd*Z
end $ ((6=39s
else (ljF{)Ml+=
begin I$t3qd{H&
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' _>m-AI4^
end 44ed79ly0)
我们可以直接写成 q.#[TI ^
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere I1Sa^7
2、收缩数据库 %+)o'nf"U
--重建索引 R\|lt)h
DBCC REINDEX n5-)/R[z
DBCC INDEXDEFRAG 9BEFr/.
--收缩数据和日志 *?ITns W<
DBCC SHRINKDB Ih}1%Jq
DBCC SHRINKFILE Sh6JF574T
3、压缩数据库 +pm[f["C.
dbcc shrinkdatabase(dbname) I6!5Yj]O"
4、转移数据库给新用户以已存在用户权限 mmXm\]r>4
exec sp_change_users_login 'update_one','newname','oldname' V/d/L3p
go }x0- V8
5、检查备份集 }n_p$g[Nj/
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;Q;[*B=kE
6、修复数据库 &MZ$j46
ALTER DATABASE [dvbbs] SET SINGLE_USER ulFzZHJ
GO "syh=BC
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK gi/@j
GO $2^`Uca
ALTER DATABASE [dvbbs] SET MULTI_USER + @9.$6N
GO
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7、日志清除 j%u-dr
SET NOCOUNT ON 51C2u)HE
DECLARE @LogicalFileName sysname, `:m!~
@MaxMinutes INT, '_\;jFAM
@NewSize INT 6qWdd&1
USE tablename -- 要操作的数据库名 \c v?^AI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 {`=0 |oP}
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 7uorQfR?
@NewSize = 1 -- 你想设定的日志文件的大小(M) |BT MJ:B
-- Setup / initialize vbx6I>\Y
DECLARE @OriginalSize int u]-_<YZ'B
SELECT @OriginalSize = size 1n5(S<T
FROM sysfiles @`opDu!
WHERE name = @LogicalFileName #`TgZKDg2
SELECT 'Original Size of ' + db_name() + ' LOG is ' + TGXa,A{
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + B
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' g]c[O*NTL
FROM sysfiles | Xi%
WHERE name = @LogicalFileName u's`*T@.
CREATE TABLE DummyTrans 3A:q7#m
(DummyColumn char (8000) not null) n<sd!xmqFx
DECLARE @Counter INT, zya5Jb:Sg
@StartTime DATETIME, \Ng\B.IQ
@TruncLog VARCHAR(255) \<Sv3xy&O
SELECT @StartTime = GETDATE(), vK7\JZ>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *-W#G}O0
DBCC SHRINKFILE (@LogicalFileName, @NewSize) >d"3<S ;b
EXEC (@TruncLog) n\Fp[9+Z\
-- Wrap the log if necessary. &AVpLf:?
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Aa0b6?Jm
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) wbDM5%
AND (@OriginalSize * 8 /1024) > @NewSize FLg*R/
BEGIN -- Outer loop. Z/x*Y#0@n
SELECT @Counter = 0 f<=Fsl
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) p.}Ls)I
BEGIN -- update ]5~s"fnG
INSERT DummyTrans VALUES ('Fill Log') ih,%i4<}6m
DELETE DummyTrans ah
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SELECT @Counter = @Counter + 1 :@W.K5
END NNhL*C[_7
EXEC (@TruncLog) G22NQ~w8
END Pq*s{
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6u`F
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Zwcy4>8
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' >Vy>O&r
FROM sysfiles }i{sg#
WHERE name = @LogicalFileName dzK{
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DROP TABLE DummyTrans [b{CkX06
SET NOCOUNT OFF aQ^umrj@?9
8、说明:更改某个表 )"f
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exec sp_changeobjectowner 'tablename','dbo' CT0l!J~5m~
9、存储更改全部表 C%*k.$#r!
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Mb3}7 @/[
@OldOwner as NVARCHAR(128), 5aad$f
@NewOwner as NVARCHAR(128) .=m,hu~
AS 1im^17X
DECLARE @Name as NVARCHAR(128) +_XmlX A3Z
DECLARE @Owner as NVARCHAR(128) l4n)#?Q?
DECLARE @OwnerName as NVARCHAR(128) 8+]hpa,q
DECLARE curObject CURSOR FOR y;mj^/SxK
select 'Name' = name, lo%;aK
'Owner' = user_name(uid) AL$&|=C-$
from sysobjects izh<I0
where user_name(uid)=@OldOwner *Av"JAX
order by name &g2 Eptx#
OPEN curObject q-nSLE+_;
FETCH NEXT FROM curObject INTO @Name, @Owner x^Yl*iq
WHILE(@@FETCH_STATUS=0) Kvsh
BEGIN gtUUsQ%y .
if @Owner=@OldOwner KH\b_>wU2
begin &//wSlL3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) n JPyM/p
exec sp_changeobjectowner @OwnerName, @NewOwner {t};-q!v$j
end qE'9QQ>:b
-- select @name,@NewOwner,@OldOwner e8YMX&0%
FETCH NEXT FROM curObject INTO @Name, @Owner hTP:[w)
END 6wco&7
close curObject
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deallocate curObject ]Jh+'RK\#
GO 1ygpp0IGJ
10、SQL SERVER中直接循环写入数据 QwhRNnE=
declare @i int PoEqurH0
set @i=1 .2J
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while @i<30 VMoSLFp^R
begin ~|wbP6</:-
insert into test (userid) values(@i) E\gim<]
set @i=@i+1 Kwc6mlw~M
end VqL.iZ-
小记存储过程中经常用到的本周,本月,本年函数 +[SgO}sF
Dateadd(wk,datediff(wk,0,getdate()),-1) x0d~i!d
Dateadd(wk,datediff(wk,0,getdate()),6) 9qS"uj
Dateadd(mm,datediff(mm,0,getdate()),0) uKgZ$-'
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) lL]y~u
Dateadd(yy,datediff(yy,0,getdate()),0) Y>jiXl?&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) AeAp0cbet
上面的SQL代码只是一个时间段 ;3_l@dP"
Dateadd(wk,datediff(wk,0,getdate()),-1) 7ugZE93!
Dateadd(wk,datediff(wk,0,getdate()),6) O;7)Hjw t
就是表示本周时间段. &uC@|dbC5
下面的SQL的条件部分,就是查询时间段在本周范围内的: [AV4m
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) eNiaM6(J
而在存储过程中 `jS T
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?\8?%Qk
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) j~j\\Y