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。 L(Twclrb
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一、基础 T|BlFJ0"
1、说明:创建数据库 -A<@Pg
CREATE DATABASE database-name 7"aN7Q+EbI
2、说明:删除数据库 A+dx7anUz
drop database dbname @#W4?L*D
3、说明:备份sql server Ieq_XF]U
--- 创建 备份数据的 device :^{KY(3
USE master z{1A x
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' UTu~"uCR
--- 开始 备份 \VOv&s;h
BACKUP DATABASE pubs TO testBack viYrPhH+z
4、说明:创建新表 YfT
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) FT6C KsM"
根据已有的表创建新表: b~tu;:
A:create table tab_new like tab_old (使用旧表创建新表) qfCZ
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B:create table tab_new as select col1,col2... from tab_old definition only '9.@r\g
5、说明:删除新表 M"s:*c_6
drop table tabname iOv>g-t:
6、说明:增加一个列 =e# h;x2
Alter table tabname add column col type :'<;]~f
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。 /P9fcNP{y
7、说明:添加主键: Alter table tabname add primary key(col) B;8Zl m9
说明:删除主键: Alter table tabname drop primary key(col) J`[jub
8、说明:创建索引:create [unique] index idxname on tabname(col....)
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删除索引:drop index idxname yZp/P %y
注:索引是不可更改的,想更改必须删除重新建。 |gxPuAXa)
9、说明:创建视图:create view viewname as select statement gS[B;+d
删除视图:drop view viewname ;g#nGs>
10、说明:几个简单的基本的sql语句 ]5a3e+
选择:select * from table1 where 范围 /2=9i84
插入:insert into table1(field1,field2) values(value1,value2) `.~S/$a.&
删除:delete from table1 where 范围 w<!,mL5 N
更新:update table1 set field1=value1 where 范围 \l3z<\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! F?a
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排序:select * from table1 order by field1,field2 [desc] aizws[C
总数:select count as totalcount from table1 /]J\/Z>
求和:select sum(field1) as sumvalue from table1 9@"pR;X@
平均:select avg(field1) as avgvalue from table1 ;Q vQ fV4
最大:select max(field1) as maxvalue from table1 q#8\BOTP |
最小:select min(field1) as minvalue from table1 SOsz=bVx
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11、说明:几个高级查询运算词 }L|B@fW
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A: UNION 运算符 85dC6wI4K
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Q
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B: EXCEPT 运算符 f &NX~(
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 MRo_An+
C: INTERSECT 运算符 j`@`M*)GB
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 q!U$\Q&
注:使用运算词的几个查询结果行必须是一致的。 .UX4p
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12、说明:使用外连接 kUGFg{"
A、left outer join: GL9'dL|
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。 R%2.N!8v
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 7>MG8pf3a
B:right outer join:
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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。 W)f=\.7
C:full outer join: vmNI$KZM
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。 j7w9H/XF}
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二、提升 <"p-0=IgJ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l SKq
法一:select * into b from a where 1<>1 L;?h)8
法二:select top 0 * into b from a , :K{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) xuqG)HthRS
insert into b(a, b, c) select d,e,f from b; 4/*@cW
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) |%XcI3@*
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }JQy&V%
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. b[:m[^
4、说明:子查询(表名1:a 表名2:b) ~-H3]
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) ?771e:>S-
5、说明:显示文章、提交人和最后回复时间 b=sY%(2s
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b }zkFl{/u
6、说明:外连接查询(表名1:a 表名2:b) `mD!z.`U
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :F[s
7、说明:在线视图查询(表名1:a ) J_yXL7d
select * from (SELECT a,b,c FROM a) T where t.a > 1; `w4'DB-R)
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 U8>4Cl J4
select * from table1 where time between time1 and time2 ()Wu_Q
select a,b,c, from table1 where a not between 数值1 and 数值2 [P~7kNFOh
9、说明:in 的使用方法 UB>BVBCt
select * from table1 where a [not] in ('值1','值2','值4','值6') v
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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 3
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) F_w+8)DZ
11、说明:四表联查问题: Bnwq!i!M
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 ..... JP( tf+
12、说明:日程安排提前五分钟提醒 ~bzac2Rp
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *m>[\)
13、说明:一条sql 语句搞定数据库分页 RiQg]3oY
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 Jo;&~/V
14、说明:前10条记录 N5K2Hv<"
select top 10 * form table1 where 范围 <9xr?i=
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!/d
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) F3o"ETle
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 ~9k E.
(select a from tableA ) except (select a from tableB) except (select a from tableC) ^ ~1QA
17、说明:随机取出10条数据 |XNw&X1VF
select top 10 * from tablename order by newid() ui`EODhA(
18、说明:随机选择记录 {/5aF_0D.
select newid() o4yl3o
19、说明:删除重复记录 }C["'tLX
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) EAWBgOO8iC
20、说明:列出数据库里所有的表名 G9jf]Ye;
select name from sysobjects where type='U' )'7Qd(4WT
21、说明:列出表里的所有的 O+<+yQl
select name from syscolumns where id=object_id('TableName') "8?Fl&=Q
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。 qvWi;
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 c}),yQ|!:
显示结果: yEh{9S%6p
type vender pcs ndN*X'
电脑 A 1 @\oZ2sB
电脑 A 1 ?0sTx6x@
光盘 B 2 %Q}(.h%M
光盘 A 2 ld|GY>rH
手机 B 3 6'uCwAQU
手机 C 3 aYc<C$:NC"
23、说明:初始化表table1 X+u1p?
TRUNCATE TABLE table1 %`]!atH
24、说明:选择从10到15的记录 hG<[F@d
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc k}}'fA
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三、技巧 N|"kuRN#
1、1=1,1=2的使用,在SQL语句组合时用的较多 jyyig%
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Xj30bt
如: Y+$]N:\F\
if @strWhere !='' -j rAk
begin HSU?4=Q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere HFyQ$pbBU
end !OPHS^L
else _tjexS'
begin .qYQ3G'V
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' #v~dhx=R
end O<@L~S]
我们可以直接写成 "s zJ[
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *h).V&::O
2、收缩数据库 c3#eL
--重建索引 QKVOc,Fp7i
DBCC REINDEX EX, {1^h
DBCC INDEXDEFRAG -,g.39u
--收缩数据和日志 ve.P{;;Ky
DBCC SHRINKDB &e*@:5Z:k
DBCC SHRINKFILE ywyg(8>zE
3、压缩数据库 Mty[)+se
dbcc shrinkdatabase(dbname) _"t>72
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4、转移数据库给新用户以已存在用户权限 cCx{
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exec sp_change_users_login 'update_one','newname','oldname' cud9oJ-=;
go 7D 3-/_ v
5、检查备份集 >/}p{Tj
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' :.a184ax
6、修复数据库 %WmTG }L)
ALTER DATABASE [dvbbs] SET SINGLE_USER 'q}f3u >
GO [C;Neslo
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK (LXYx<
GO fshG ~L7S9
ALTER DATABASE [dvbbs] SET MULTI_USER y[AB,Dd
GO uD{ xs
7、日志清除 ln,9v
SET NOCOUNT ON X+,0;% p
DECLARE @LogicalFileName sysname, G7-k ,P^
@MaxMinutes INT, ,BGUIu6
@NewSize INT PVljb=8F
USE tablename -- 要操作的数据库名 8)"lCIf
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 W| 0))5a
@MaxMinutes = 10, -- Limit on time allowed to wrap log. i!RYrae
@NewSize = 1 -- 你想设定的日志文件的大小(M) GGhk`z
-- Setup / initialize S^EAE]
DECLARE @OriginalSize int rb'mFqg*u
SELECT @OriginalSize = size eq&QWxiD*
FROM sysfiles &U}8@;
WHERE name = @LogicalFileName W|n$H`;R
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -rgdKA@)(
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + yUxz,36wZ
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' II~91IEk
FROM sysfiles : vgn0IQ
WHERE name = @LogicalFileName aiE\r/k8s
CREATE TABLE DummyTrans kw2d<I$]
(DummyColumn char (8000) not null) 1_c%p#?K
DECLARE @Counter INT, ^rjUye%EK
@StartTime DATETIME, 7ju38@+
@TruncLog VARCHAR(255) r[GH#vF;7
SELECT @StartTime = GETDATE(), XsFzSm
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' zA3r&stN+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) IQ-l%x[fue
EXEC (@TruncLog) asmu<
-- Wrap the log if necessary. Lg#(?tMp,'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {7%HK2='
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) >@4AxV\
AND (@OriginalSize * 8 /1024) > @NewSize 3kF+wifsz
BEGIN -- Outer loop. Cp>y<C"
SELECT @Counter = 0 CW/L(RQ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) }ALli0n`V)
BEGIN -- update = iDd{$
INSERT DummyTrans VALUES ('Fill Log') cc}#-HKR[
DELETE DummyTrans UM]3MS:[
SELECT @Counter = @Counter + 1 TGPZUyi3!=
END ocUBSK|K)
EXEC (@TruncLog) D~M R)z_p~
END o>Dd1
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + KQw>6)
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + UVgSO|Tg
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' R>;&4Sjr
FROM sysfiles e:.?T\
WHERE name = @LogicalFileName ?gvu
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DROP TABLE DummyTrans E_Y!in
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SET NOCOUNT OFF Bm%|WQK
8、说明:更改某个表 lq,]E/<&
exec sp_changeobjectowner 'tablename','dbo' l]&x~K}
9、存储更改全部表 &o1k_!25
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ) vVf- zU
@OldOwner as NVARCHAR(128), )"6"g9A
@NewOwner as NVARCHAR(128) 1cRF0MI
AS e+VE FWz
DECLARE @Name as NVARCHAR(128) h9iQn<lp4.
DECLARE @Owner as NVARCHAR(128) 5tZ0zr
DECLARE @OwnerName as NVARCHAR(128) R?- zJ ;
DECLARE curObject CURSOR FOR qcQq.cS_'N
select 'Name' = name, X{ 6a
'Owner' = user_name(uid) BB(v,W
from sysobjects $4)L~g|
where user_name(uid)=@OldOwner r=AA
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order by name v*<rNZI
OPEN curObject koD}o^U#
FETCH NEXT FROM curObject INTO @Name, @Owner u!F\`Gfm_
WHILE(@@FETCH_STATUS=0) r_
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BEGIN C=cn.CX
if @Owner=@OldOwner ]?oJxW.
begin pQC|_T#u
set @OwnerName = @OldOwner + '.' + rtrim(@Name) s| Q1;%Tj
exec sp_changeobjectowner @OwnerName, @NewOwner nXI8 `7D
end c813NHW
-- select @name,@NewOwner,@OldOwner <X1lq9 lW
FETCH NEXT FROM curObject INTO @Name, @Owner KH=3HN}
END $\~cWpv
close curObject Y3(I;~$!
deallocate curObject yaWY>sB
GO +*Uv+oC|
10、SQL SERVER中直接循环写入数据 x7`+T1IJ
declare @i int ;)P=WS:=
set @i=1 S{f,EBE
while @i<30 }:;UnE}
begin Hr!$mf)h
insert into test (userid) values(@i) -Wh 2hWg+
set @i=@i+1 {9x>@p/
end KT >Y^
小记存储过程中经常用到的本周,本月,本年函数 ?d{O'&|:
Dateadd(wk,datediff(wk,0,getdate()),-1) %^nNt:N0
Dateadd(wk,datediff(wk,0,getdate()),6) \+l_H4\`K
Dateadd(mm,datediff(mm,0,getdate()),0) u%I%4 gM
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) #e,TS`"eD
Dateadd(yy,datediff(yy,0,getdate()),0) g#7Q-n3^
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .c0u##/0
上面的SQL代码只是一个时间段 v9S=$Aj
Dateadd(wk,datediff(wk,0,getdate()),-1) #Er"i
Dateadd(wk,datediff(wk,0,getdate()),6) (uhE'IQ{(
就是表示本周时间段. <o*b6m%
下面的SQL的条件部分,就是查询时间段在本周范围内的: 6-J}ZfGj
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) y'>JT/Q5
而在存储过程中 6%>'n?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 6?C';1
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) *vEj\