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。 AUjTcu>i
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一、基础 _yB9/F
1、说明:创建数据库 BvW gH.OX
CREATE DATABASE database-name >fj$wOq
2、说明:删除数据库 &|\}\+0Z
drop database dbname Vv)E41
3、说明:备份sql server [O+^eE6h
--- 创建 备份数据的 device >\.[}th}
USE master jKV?!~/F
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' U6'haPlOk%
--- 开始 备份 No&[ \;
BACKUP DATABASE pubs TO testBack 6N+)LF}P b
4、说明:创建新表 ftU5A@(T
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) jzA8f+:q
根据已有的表创建新表: s1\BjSzk
A:create table tab_new like tab_old (使用旧表创建新表) ZUJOBjb`
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B:create table tab_new as select col1,col2... from tab_old definition only 9c %Tv
5、说明:删除新表 ^?]H$e
drop table tabname 0:+uw`
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6、说明:增加一个列 _%Ld
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Alter table tabname add column col type k\<Ln
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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。 ZpctsCz]
7、说明:添加主键: Alter table tabname add primary key(col) *#^1rKGWK
说明:删除主键: Alter table tabname drop primary key(col) !K~$-jlT
8、说明:创建索引:create [unique] index idxname on tabname(col....) EEZ2Gu6c
删除索引:drop index idxname Q!e0Vb
注:索引是不可更改的,想更改必须删除重新建。 jh&vq=PH
9、说明:创建视图:create view viewname as select statement "jc)N46
删除视图:drop view viewname N_Ld,J%g
10、说明:几个简单的基本的sql语句 ~tuFjj^
选择:select * from table1 where 范围 8si^HEQ8
插入:insert into table1(field1,field2) values(value1,value2) b{>dOI*.}
删除:delete from table1 where 范围 ({nSs5)$
更新:update table1 set field1=value1 where 范围 &p4<@k\L
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! JsEEAM:w
排序:select * from table1 order by field1,field2 [desc] _1c_TM h}9
总数:select count as totalcount from table1 9:w,@Phe
求和:select sum(field1) as sumvalue from table1 >b?)WNk
平均:select avg(field1) as avgvalue from table1 $cU/Im`
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 rK)
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11、说明:几个高级查询运算词 J\D3fh97-
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A: UNION 运算符 &)jZ|Q~
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 1W<_5 j_
B: EXCEPT 运算符 /- 4B)mL
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 QXj(Urp
C: INTERSECT 运算符
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INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 l8Qi^<i/
注:使用运算词的几个查询结果行必须是一致的。 P$Ru NF
12、说明:使用外连接 d( g_y m*
A、left outer join: M)^9e?
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。 ):ZumG#o
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 }_;!E@
B:right outer join: Hvo27THLo
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。 S`w)b'B!M
C:full outer join: kk+8NwM1
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。 ye2Oh7
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二、提升 <U pjAuG8
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) TN`:T.B
法一:select * into b from a where 1<>1 7'uc;5:
法二:select top 0 * into b from a E/']M~Q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;g]+MLV9
insert into b(a, b, c) select d,e,f from b; qDb}b d5
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) b.;}Hq>
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {2@96o2}
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Dx'e+Bm
4、说明:子查询(表名1:a 表名2:b) Ngnjr7Q={T
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) =>*N W9c
5、说明:显示文章、提交人和最后回复时间 w,9F riW
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b cyNLeg+O*
6、说明:外连接查询(表名1:a 表名2:b) ?9TogW>W
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c bp,CvQ'}a
7、说明:在线视图查询(表名1:a ) >O~5s.1u
select * from (SELECT a,b,c FROM a) T where t.a > 1; lZ_k307
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 p#2th`M:P1
select * from table1 where time between time1 and time2 P7-3Vf_L
select a,b,c, from table1 where a not between 数值1 and 数值2 Kx0dOkE
9、说明:in 的使用方法 }DaYO\:yK*
select * from table1 where a [not] in ('值1','值2','值4','值6') %A3Jd4DH
10、说明:两张关联表,删除主表中已经在副表中没有的信息 sN2l[Ous
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) D9en
11、说明:四表联查问题: ,RQ-w2j?
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 ..... rI/KrBM
12、说明:日程安排提前五分钟提醒 mGvP9E"&
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 sSUd;BYf
13、说明:一条sql 语句搞定数据库分页 K>y+3HN[6
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 <!^Z|E
14、说明:前10条记录 PAkW[;GSDh
select top 10 * form table1 where 范围 LKcrr;
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.) e{&gF1"[
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
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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 fF%r$`2
(select a from tableA ) except (select a from tableB) except (select a from tableC) x]Ef}g
17、说明:随机取出10条数据 0i"OG( ,
select top 10 * from tablename order by newid() ~_%[j8o&l
18、说明:随机选择记录 g 7X>i:
select newid() |:z%7J3wP
19、说明:删除重复记录 Yo:&\a K[
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) tPsU7bFk
20、说明:列出数据库里所有的表名 odDt.gQXU
select name from sysobjects where type='U' DxHeZQ"LL
21、说明:列出表里的所有的 7f>n`nq?
select name from syscolumns where id=object_id('TableName') rtm28|0H'
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。 4hIC&W~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 qM+T Wp
显示结果: 8@-US ,|
type vender pcs A7H=#L+C
电脑 A 1 R9(^CWs
电脑 A 1 -|mABHjx*
光盘 B 2 *?{)i~
光盘 A 2 $`%.Y&A
手机 B 3 /l
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手机 C 3 |UG)*t/
23、说明:初始化表table1 T[~X~dqwn"
TRUNCATE TABLE table1 [z\*Zg
24、说明:选择从10到15的记录 :[doYizk:
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc lV8Mr6m
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三、技巧 v;SJgZK
1、1=1,1=2的使用,在SQL语句组合时用的较多 8J} J;Ga
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 6%TV X
如: X`&E,;bIb
if @strWhere !='' _),@^^&x
begin k.%F!sK
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Z_%>yqDC
end 0!Yi.'+
else 8MIHp[vm%
begin Liofv4![
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' _>s.V`N'
end 9 wc=B(a|
我们可以直接写成 "LYob}_z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 3XIxuQwf
2、收缩数据库 3iB8QO;pp
--重建索引 J{H475GqiT
DBCC REINDEX n}2}4^
DBCC INDEXDEFRAG &3rh{" ^9
--收缩数据和日志 q_!3<.sf
DBCC SHRINKDB $/Mk.(3'P
DBCC SHRINKFILE .$Y[>9
3、压缩数据库 @I%m}>4Jm
dbcc shrinkdatabase(dbname) bkb}M)C
4、转移数据库给新用户以已存在用户权限 @uc%]V<:k
exec sp_change_users_login 'update_one','newname','oldname' k,2%%m
go _ v-sb(*
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5、检查备份集 "YivjHa7H
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' aD.A +e s
6、修复数据库 -Jb
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ALTER DATABASE [dvbbs] SET SINGLE_USER sviGS&J9h
GO dG1qrh9_-
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,\VNs'j
GO 74Lq!e3hMF
ALTER DATABASE [dvbbs] SET MULTI_USER 0'gJSrgNI
GO y<)x`&pcD
7、日志清除 o^Ms(?K%t
SET NOCOUNT ON ,$*$w<
DECLARE @LogicalFileName sysname, ZW2U9
@MaxMinutes INT, <|v]9`'
@NewSize INT 4]Krx
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USE tablename -- 要操作的数据库名 (|W@p\Q
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 J:t1W=lJ3
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ;%Qu;FtC
@NewSize = 1 -- 你想设定的日志文件的大小(M) J5429Soo
-- Setup / initialize *\emRI>
DECLARE @OriginalSize int $///N+B
SELECT @OriginalSize = size f)>=.sp
FROM sysfiles }z}oVc
WHERE name = @LogicalFileName v=!]t=P)t
SELECT 'Original Size of ' + db_name() + ' LOG is ' + `Dj-(~x
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + $cc]pJy"}
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' QHK$2xtq|
FROM sysfiles y:xZ(RgfF
WHERE name = @LogicalFileName Iu=iC.50}
CREATE TABLE DummyTrans *f1MgP*GKF
(DummyColumn char (8000) not null) tip\vS)
DECLARE @Counter INT, n<?:!f`
@StartTime DATETIME, Wfp[)MM;
@TruncLog VARCHAR(255) L \pe
SELECT @StartTime = GETDATE(), <`BUk< uf#
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' _Y=>^K]9K
DBCC SHRINKFILE (@LogicalFileName, @NewSize) m+zzhv1
EXEC (@TruncLog) EiSS_Lc
-- Wrap the log if necessary. G> "w$Us
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired <f1Pj
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Y7= *-
AND (@OriginalSize * 8 /1024) > @NewSize sk9*3d5I
BEGIN -- Outer loop. LEG
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SELECT @Counter = 0 p"w"/[8
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Ye T[KjX
BEGIN -- update $`mxOcBmQ
INSERT DummyTrans VALUES ('Fill Log') fs\l*nBig
DELETE DummyTrans g$~ktr+%
SELECT @Counter = @Counter + 1 LyH{{+V
END \It8+^d@
EXEC (@TruncLog) F8f@^LVM/
END 2]hQ56Yv3
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 525W;
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Jc/*w
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' J&wrBVv1uk
FROM sysfiles 0KE+RzrB
WHERE name = @LogicalFileName {U>B\D
DROP TABLE DummyTrans e+j7dmGa
SET NOCOUNT OFF fM6Pw6k
8、说明:更改某个表 J;HkR9<C
exec sp_changeobjectowner 'tablename','dbo' -m3O\X
9、存储更改全部表 ;~3CuN8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch s7[du_)
@OldOwner as NVARCHAR(128), gh#9<
@NewOwner as NVARCHAR(128) WL:CBE#
AS j@
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DECLARE @Name as NVARCHAR(128) x=(Q$Hl5
DECLARE @Owner as NVARCHAR(128) To.CY^M
DECLARE @OwnerName as NVARCHAR(128) 4cDjf~n
DECLARE curObject CURSOR FOR [LbUlNq^B@
select 'Name' = name, yHsmX2s
'Owner' = user_name(uid) /I(IT=kp
from sysobjects x\T 9V~8a
where user_name(uid)=@OldOwner [@(M%
order by name hCS|(8g
OPEN curObject c 2t<WRG
FETCH NEXT FROM curObject INTO @Name, @Owner tNj-~r
WHILE(@@FETCH_STATUS=0) |uf{:U)
BEGIN qbrY5;U
if @Owner=@OldOwner MEf`&<t
begin I&%{%*y
set @OwnerName = @OldOwner + '.' + rtrim(@Name) I?r7dQEm
exec sp_changeobjectowner @OwnerName, @NewOwner =:Ahg
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end 9$U@h7|Q`
-- select @name,@NewOwner,@OldOwner
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FETCH NEXT FROM curObject INTO @Name, @Owner 5n{J}0C
END Oh)s"f\N
close curObject Jas=D
deallocate curObject YW9r'{(D(I
GO }ya@*jH
10、SQL SERVER中直接循环写入数据 .LMOmc=(
declare @i int ,41Z_h
set @i=1 0se0AcrW
while @i<30 `Tw DR6&
begin '9d<vWg
insert into test (userid) values(@i) ML eo3
set @i=@i+1 NEp
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end K=lm9K
小记存储过程中经常用到的本周,本月,本年函数 0oR'"Vo
Dateadd(wk,datediff(wk,0,getdate()),-1) A)v!
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Dateadd(wk,datediff(wk,0,getdate()),6) IDCuS
Dateadd(mm,datediff(mm,0,getdate()),0) }Rl^7h<!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) f+3ico]f@
Dateadd(yy,datediff(yy,0,getdate()),0) dRC
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) wMc/Og
上面的SQL代码只是一个时间段 4PdJ
Dateadd(wk,datediff(wk,0,getdate()),-1) p=13tQS<
Dateadd(wk,datediff(wk,0,getdate()),6) ^<u9I5?
就是表示本周时间段. 5@ c/,6l
下面的SQL的条件部分,就是查询时间段在本周范围内的: n@1;5)&k~
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) q-?
k=RX`
而在存储过程中 PH!^ww6
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (S<Z@y+d
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) j<,Ho4v}_