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。 4sj:%%UE
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一、基础 Oyfc!
1、说明:创建数据库 }!^/<|$=
CREATE DATABASE database-name 9/La_:K
2、说明:删除数据库 7<'4WHi;@s
drop database dbname btQDG
3、说明:备份sql server :RYh@.
--- 创建 备份数据的 device z /
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USE master {;iG}j K
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Z$8X1(o
--- 开始 备份 3A~53W$M
BACKUP DATABASE pubs TO testBack n'dxa<F2|
4、说明:创建新表 qTGEi
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 6"
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根据已有的表创建新表: im}=
A:create table tab_new like tab_old (使用旧表创建新表) 6b-j
B:create table tab_new as select col1,col2... from tab_old definition only )$h<9e
5、说明:删除新表 p=tj>{
drop table tabname wEMh !jAbv
6、说明:增加一个列 sz5&P )X
Alter table tabname add column col type g?(h{r`
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 O{sb{kk
7、说明:添加主键: Alter table tabname add primary key(col) L(a){<c
说明:删除主键: Alter table tabname drop primary key(col) 3C=|
8、说明:创建索引:create [unique] index idxname on tabname(col....) ,mu=#}a@}
删除索引:drop index idxname #0i] g)
注:索引是不可更改的,想更改必须删除重新建。 ~@3X&E0S
9、说明:创建视图:create view viewname as select statement h{&X`$
删除视图:drop view viewname c<'Pt4LY
10、说明:几个简单的基本的sql语句 Z+zx*(X
选择:select * from table1 where 范围 >bKN$,Qen
插入:insert into table1(field1,field2) values(value1,value2) (TQx3DGq
删除:delete from table1 where 范围 **zh>Y}6
更新:update table1 set field1=value1 where 范围 (c{<JYEC
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %E!^SF?Y
排序:select * from table1 order by field1,field2 [desc] Anpx%NVo
总数:select count as totalcount from table1 ~AD%aHR
求和:select sum(field1) as sumvalue from table1 $LS$:%i4
平均:select avg(field1) as avgvalue from table1 3#d5.Ut
最大:select max(field1) as maxvalue from table1 INm21MS$
最小:select min(field1) as minvalue from table1 ~"<AYJlO
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11、说明:几个高级查询运算词 /Dn,;@ZwAi
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A: UNION 运算符 CB<i
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。 YKjm_)8]w
B: EXCEPT 运算符 8=]R6[,fD
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。 -SZW[T<N"
C: INTERSECT 运算符 l7{Xy_66
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。 l9U^[;D
注:使用运算词的几个查询结果行必须是一致的。 )PM&x
12、说明:使用外连接 rPK)=[MZ
A、left outer join: Z3ucJH/)V
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。 5LT{]&`9
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 wKjL}1.k
B:right outer join: {=(GY@yU/
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。 p8%/T>hK
C:full outer join: PMDx5-{A/t
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。 ]F,mj-?4x
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二、提升 ~*Fbs! ;,
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) CS:"F) at
法一:select * into b from a where 1<>1 |@J:A!
法二:select top 0 * into b from a c,$ >u,4
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) B( ]=I@L=W
insert into b(a, b, c) select d,e,f from b; RCFocOOn
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) gAy,uP~,
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 K_@[%
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. $6BD6\@
4、说明:子查询(表名1:a 表名2:b) yu3T5@Ww
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) Gw"H#9J}
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5、说明:显示文章、提交人和最后回复时间 ,ux?wa+
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b !nQ!J+ g
6、说明:外连接查询(表名1:a 表名2:b) 4M)
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 9-<EeV_/
7、说明:在线视图查询(表名1:a ) }Q 7~tu
select * from (SELECT a,b,c FROM a) T where t.a > 1; &cty&(2p
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 -t92! O
select * from table1 where time between time1 and time2 AE:IXP|c
select a,b,c, from table1 where a not between 数值1 and 数值2 'USol<
9、说明:in 的使用方法 hOI|#(-
select * from table1 where a [not] in ('值1','值2','值4','值6') R$'0<y8E*]
10、说明:两张关联表,删除主表中已经在副表中没有的信息 B(x$
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) l;4},N
11、说明:四表联查问题: PD@]2lY(
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 ..... )qGw!^8
12、说明:日程安排提前五分钟提醒 67/&AiS?
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *\?tW]8<
13、说明:一条sql 语句搞定数据库分页 eOZ0L1JM!
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 gNon*\a,-B
14、说明:前10条记录 _z:7Dj#
select top 10 * form table1 where 范围 p[E}:kak_-
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.) -Y#YwBy;M
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [4V{~`sF
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 [25[c><:w"
(select a from tableA ) except (select a from tableB) except (select a from tableC) }L.xt88
17、说明:随机取出10条数据 HPGMR4=ANS
select top 10 * from tablename order by newid() o%ZtE
18、说明:随机选择记录 (#Vkk]-p
select newid() :iWW2fY
19、说明:删除重复记录 PgNg1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &E0d{2
20、说明:列出数据库里所有的表名 PZVh)6f"c
select name from sysobjects where type='U' mnKSO
21、说明:列出表里的所有的 8IErLu }
select name from syscolumns where id=object_id('TableName') b?6-lYE>L
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。 z1LN|+\}
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 `lAe2l^
显示结果: |sf&t
type vender pcs OH2Xxr[bQ
电脑 A 1 2s(c#$JVS
电脑 A 1 dLV>FpA\
光盘 B 2 5PY,}1`
光盘 A 2 FLT4:B7
手机 B 3 ;pK/t=$
手机 C 3 !Cq2<[K#
23、说明:初始化表table1 !f
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TRUNCATE TABLE table1 -;/;d z;
24、说明:选择从10到15的记录 <:[P&Y
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 1#KE4(
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三、技巧 SE%B&8ZD
1、1=1,1=2的使用,在SQL语句组合时用的较多 m+y5Q&;f
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ('H[[YODh
如: ~j%g?;#*
if @strWhere !='' 5)g6yV'
begin :VP*\K/:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ao2NwH##
end ~>h_#sIBC
else "E4;M/
begin !j'9>G{T
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' >/,7j:X
end C&Nga
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我们可以直接写成 |"4+~z%/9!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere R>BZQugZ~
2、收缩数据库 QU4/hS;Ux
--重建索引 cg16|
DBCC REINDEX qmNg Ez%
DBCC INDEXDEFRAG ,(h:0L2v7d
--收缩数据和日志 8ZY F%
DBCC SHRINKDB T$ <l<.Qd
DBCC SHRINKFILE q J)[2:.G
3、压缩数据库 ELh`|X
dbcc shrinkdatabase(dbname) o :`>r/SlL
4、转移数据库给新用户以已存在用户权限 XH9Y|FX%#
exec sp_change_users_login 'update_one','newname','oldname' WCK;r{p%I
go drr
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5、检查备份集 r_8[}|7;
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ulY8$jB
6、修复数据库 r_m*$r~f
ALTER DATABASE [dvbbs] SET SINGLE_USER P?- #d\qi
GO |?zFm
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ZbmBwW_ 7
GO A .]o&S}
ALTER DATABASE [dvbbs] SET MULTI_USER Nqf6CPXE
GO #$vQT}
7、日志清除 f{s}[p~
SET NOCOUNT ON O$<m(~[S
DECLARE @LogicalFileName sysname, K9{]v=#I
@MaxMinutes INT, fk*$}f
@NewSize INT >_R,^iH"
USE tablename -- 要操作的数据库名 ^T(v4'7
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ,;RAPT4
@MaxMinutes = 10, -- Limit on time allowed to wrap log. :Q~Rb<']{x
@NewSize = 1 -- 你想设定的日志文件的大小(M) }vppn=[Y
-- Setup / initialize \6]Uj+
DECLARE @OriginalSize int 9$]I3k
SELECT @OriginalSize = size BU3VXnqT[
FROM sysfiles Y9YE:s
WHERE name = @LogicalFileName kU*Fif
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ??X3teO{
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <4l;I*:2&
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' [SnnOq Ww
FROM sysfiles 0rnne
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WHERE name = @LogicalFileName Z/Vb _
CREATE TABLE DummyTrans Me*woCos'
(DummyColumn char (8000) not null) %(f&).W
DECLARE @Counter INT, ssf.ef$
@StartTime DATETIME, 3&39M&
@TruncLog VARCHAR(255) l1<]pdLTR
SELECT @StartTime = GETDATE(), dm;C @.ML
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @m#1[n;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) n'WhCrW
EXEC (@TruncLog) _9y
-- Wrap the log if necessary. 6),U(e%
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired puv/+!q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =f{)!uW<4
AND (@OriginalSize * 8 /1024) > @NewSize =g]Ln)jc
BEGIN -- Outer loop. R
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SELECT @Counter = 0 Z@Tb3N/[
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 17hFwo`
BEGIN -- update A.f!SYV6
INSERT DummyTrans VALUES ('Fill Log') ymNL`GYN[
DELETE DummyTrans Ptj,9bf<\
SELECT @Counter = @Counter + 1 w+^z{3>
END WUEjWJA-MB
EXEC (@TruncLog) E~[v.3`
END &]d-R
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Wciw6.@
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + cJIA/HQe
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' u]<7}R@s
FROM sysfiles oRp;9
WHERE name = @LogicalFileName khXp}p!Zm
DROP TABLE DummyTrans .>/Tc
SET NOCOUNT OFF h'QEwW
8、说明:更改某个表
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exec sp_changeobjectowner 'tablename','dbo' B#zu<z
9、存储更改全部表 EZN38T
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 0j'H5>m"
@OldOwner as NVARCHAR(128), )MV`(/BC*
@NewOwner as NVARCHAR(128) 0 It[Pa qG
AS D%WgE&wtM
DECLARE @Name as NVARCHAR(128) m VSaC
DECLARE @Owner as NVARCHAR(128) Or({|S9d2
DECLARE @OwnerName as NVARCHAR(128) {? a@UUvC
DECLARE curObject CURSOR FOR l(o;O.dLt
select 'Name' = name, %.NOQ<@W
'Owner' = user_name(uid) ITUwIpAE
from sysobjects :)djHPP*
where user_name(uid)=@OldOwner kdr?I9kwW
order by name !F^j\
OPEN curObject |z]O@@j$
FETCH NEXT FROM curObject INTO @Name, @Owner Xp_3EQl
WHILE(@@FETCH_STATUS=0) *>=|"ff
BEGIN R)[ l3
if @Owner=@OldOwner yf lt2 R
begin bwr}Ge
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &,4 3&pFU
exec sp_changeobjectowner @OwnerName, @NewOwner
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end "OdR"M(G\
-- select @name,@NewOwner,@OldOwner H#Aar
FETCH NEXT FROM curObject INTO @Name, @Owner l^LYSZg'R8
END QH)uh"
close curObject /4Df 'd
deallocate curObject ZysZS%
GO H@j
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10、SQL SERVER中直接循环写入数据 W-72&\7
declare @i int BAJEn6f?
set @i=1 *[ @k=!73
while @i<30 Pc{0Js5VzE
begin Q?1'
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insert into test (userid) values(@i) S4'\=w#
set @i=@i+1 8J5{}4s\f
end @2Spfj_e
小记存储过程中经常用到的本周,本月,本年函数 +WxZB
Dateadd(wk,datediff(wk,0,getdate()),-1) =P,h5J
Dateadd(wk,datediff(wk,0,getdate()),6) ^")SU(`
Dateadd(mm,datediff(mm,0,getdate()),0) bOY<C%;C
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) P
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Dateadd(yy,datediff(yy,0,getdate()),0) +!'rwD
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Y[\ZN
上面的SQL代码只是一个时间段 {I]X-+D|_
Dateadd(wk,datediff(wk,0,getdate()),-1) Gtyy^tz[
Dateadd(wk,datediff(wk,0,getdate()),6) QcXqMx
就是表示本周时间段. :(^,WOf
下面的SQL的条件部分,就是查询时间段在本周范围内的: Sz"rp9x+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) f0<'IgN
而在存储过程中 x|TLMu=3=
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) qh40nqS;9
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) L_k'r\L