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。 h3Z0NJ=xM
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一、基础 H@,(
1、说明:创建数据库 (f|3(u'e?
CREATE DATABASE database-name pVm'XP
2、说明:删除数据库 GKKf#r74
drop database dbname
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3、说明:备份sql server snyg
--- 创建 备份数据的 device vSy#[9}
USE master [Y]\sF;J
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' y"SVZ} ;|
--- 开始 备份 h"G#} C]
BACKUP DATABASE pubs TO testBack sIh,@b
4、说明:创建新表 +V6N/{^5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) %t^-Guz
根据已有的表创建新表: ,;yiV<AD
A:create table tab_new like tab_old (使用旧表创建新表) OL|UOG
B:create table tab_new as select col1,col2... from tab_old definition only d^WEfH
5、说明:删除新表 <ibEo98
drop table tabname {` Lem
6、说明:增加一个列 cvvba 60
Alter table tabname add column col type ']ussFaQ
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。 ?F9:rUyN
7、说明:添加主键: Alter table tabname add primary key(col) @9^ozgg
说明:删除主键: Alter table tabname drop primary key(col) ~vIQ-|8r:
8、说明:创建索引:create [unique] index idxname on tabname(col....) (1(dL_?
删除索引:drop index idxname HW(cA}$
注:索引是不可更改的,想更改必须删除重新建。 Q<V?rPAcx
9、说明:创建视图:create view viewname as select statement *w538Vb
删除视图:drop view viewname P*6B+8h"5g
10、说明:几个简单的基本的sql语句 D?3^>h
选择:select * from table1 where 范围 Yvu!Q
插入:insert into table1(field1,field2) values(value1,value2) fWywegh
删除:delete from table1 where 范围 0x\bDWZ_
更新:update table1 set field1=value1 where 范围 gUB%6v G\I
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Gt^Fj&^
排序:select * from table1 order by field1,field2 [desc] OXuBtW*,z+
总数:select count as totalcount from table1 q8{)27f,
求和:select sum(field1) as sumvalue from table1 o'Byuct
平均:select avg(field1) as avgvalue from table1 UmSy p\i
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 g9`z]qGWS:
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11、说明:几个高级查询运算词 ~I%m[fQ S
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A: UNION 运算符 -Fe))Y'=
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。 2R2ws.}
B: EXCEPT 运算符 {re<S<j&
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。 lV-b
C: INTERSECT 运算符 `r:n[N=Y&
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。 {f\/2k3
注:使用运算词的几个查询结果行必须是一致的。 ;{79d8/=
12、说明:使用外连接 tB_GEt2M
A、left outer join: ^b]h4z$
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。 "+iPeRF!hU
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 >'^Tp7\
B:right outer join: Uv~r]P)
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。 Y9)uy 8c
C:full outer join: fG107{!g=
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。 db%o3>>e
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二、提升 ~5[#c27E9
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 9H9 P'lx9
法一:select * into b from a where 1<>1 +pcpb)VL
法二:select top 0 * into b from a =1noT)gCR
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) I5l5fx
insert into b(a, b, c) select d,e,f from b; k[0Gz
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) |^^'GZ%a
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 dC$z q~q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. &>zzR$#1
4、说明:子查询(表名1:a 表名2:b) -s5j^U{h|
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) [eebIJs
5、说明:显示文章、提交人和最后回复时间 [%M=nJ{8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Wm{Lg0Nr
6、说明:外连接查询(表名1:a 表名2:b) (,wIbwa
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ?8AchbK;N
7、说明:在线视图查询(表名1:a ) @7Oqp-
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7cTDbc!E-
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 FA}dKE=c
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select * from table1 where time between time1 and time2 ;by`[)
select a,b,c, from table1 where a not between 数值1 and 数值2 V7Z+@e-5
9、说明:in 的使用方法
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select * from table1 where a [not] in ('值1','值2','值4','值6') ,Q8[Ur?G
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-^? ;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) hSQuML
11、说明:四表联查问题: #)&kF+
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 ..... mhZ{}~
12、说明:日程安排提前五分钟提醒 9?5'>WO
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 b*w@kLLN
13、说明:一条sql 语句搞定数据库分页 $9!2c /
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 +ML4.$lc^
14、说明:前10条记录 }w{6Ua
select top 10 * form table1 where 范围 [&e|:1
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.) F<K;tt
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) cI~uI'
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 z']TRjDbT
(select a from tableA ) except (select a from tableB) except (select a from tableC) 3mI(5~4A]?
17、说明:随机取出10条数据 0x&-/qce6W
select top 10 * from tablename order by newid() 5G!0Yy['
18、说明:随机选择记录 >/@wht4- j
select newid() TYv'#{
19、说明:删除重复记录 J?]wA1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) I!FIV^}Z(
20、说明:列出数据库里所有的表名 kjVUG >e>
select name from sysobjects where type='U' cZB?_[Cp
21、说明:列出表里的所有的 tk'1o\@p9b
select name from syscolumns where id=object_id('TableName') $T.u Iq
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 N8hiv'3
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type I$.HG]
显示结果: w$Zi'+&*
type vender pcs vGe];
电脑 A 1 c2Q KI~\x
电脑 A 1 q~esxp
光盘 B 2 1:!_AU?
光盘 A 2 6#[
手机 B 3 ]S@zhQ
手机 C 3 zSy^vM;6zf
23、说明:初始化表table1 V
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TRUNCATE TABLE table1 `1}WQS
24、说明:选择从10到15的记录 rC`pTN
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc CD}::7$
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三、技巧 E@}N}SR
1、1=1,1=2的使用,在SQL语句组合时用的较多 =E6ND8l@2
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ]Sj<1tx7f
如: M]c"4b;
if @strWhere !='' PIk2mX/D_6
begin in-|",O`Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }
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end f4%Z~3P
else >A5*=@7bY?
begin JVfSmxy.
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' srzlr-J
end V{jQ=<)@e
我们可以直接写成 {KQ-QKxxS
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere &>nB@SQZ
2、收缩数据库 v2w|?26Lf
--重建索引 olm0O (9
DBCC REINDEX _3Kow{y\
DBCC INDEXDEFRAG h^QLvOuR
--收缩数据和日志 pc/x&VY%
DBCC SHRINKDB p{@j M
DBCC SHRINKFILE >X@4wP7l
3、压缩数据库 u-s*3Lg&
dbcc shrinkdatabase(dbname) 0r_3:#Nn
4、转移数据库给新用户以已存在用户权限 ~,^pya
exec sp_change_users_login 'update_one','newname','oldname' 1k)31GEQw
go d/"%fpp^0G
5、检查备份集 NqlU?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' e
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6、修复数据库 fA$2jbGW
ALTER DATABASE [dvbbs] SET SINGLE_USER KPi_<LuK
GO rF^H\U:w
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK =I.uf
GO ,+P2B%2c
ALTER DATABASE [dvbbs] SET MULTI_USER 2y"L&3W
GO @vc9L
7、日志清除 c9ye[81
SET NOCOUNT ON &gLXS1O
DECLARE @LogicalFileName sysname, gB_gjn\
@MaxMinutes INT, a
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@NewSize INT m2a[E0
USE tablename -- 要操作的数据库名 W-RqooEv
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 C6JwJYa
@MaxMinutes = 10, -- Limit on time allowed to wrap log. M!`&Z9N
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2^X<n{0N)
-- Setup / initialize Y=?Tm,z4
DECLARE @OriginalSize int Cl8S_Bz
SELECT @OriginalSize = size o$p]
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FROM sysfiles +;Pkpuu
WHERE name = @LogicalFileName *b4W+E
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Z!+n/ D-1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 5_\1f|,
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1rIL[(r4
FROM sysfiles GU0[K#%
WHERE name = @LogicalFileName w-"tA`F4
CREATE TABLE DummyTrans F05]6NVv
(DummyColumn char (8000) not null) 6Z@?W
DECLARE @Counter INT, l3Qt_I)L
@StartTime DATETIME, V. e30u5
@TruncLog VARCHAR(255) 5yL\@7u`
SELECT @StartTime = GETDATE(), g [u*`]-;v
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :bq${
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {^.q6,l
EXEC (@TruncLog) r,<p#4(>_
-- Wrap the log if necessary. W5uC5C*,l
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired bXz*g`=;
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _<6E>"*m
AND (@OriginalSize * 8 /1024) > @NewSize `l'Ine11
BEGIN -- Outer loop. *x/H
SELECT @Counter = 0 +ovT?CMo
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) R('\i/fy
BEGIN -- update 'kSm}}y
INSERT DummyTrans VALUES ('Fill Log') I{$TMkh[
DELETE DummyTrans I.gF38Mx
SELECT @Counter = @Counter + 1 3>v-,S+
END y&A&d-
EXEC (@TruncLog) '5lwlF
END (sW$2a
SELECT 'Final Size of ' + db_name() + ' LOG is ' + mKLWz1GZ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + cte
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 12V-EG i
FROM sysfiles M_O) w^
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WHERE name = @LogicalFileName ~#dfZa&
DROP TABLE DummyTrans *EPJeblAV
SET NOCOUNT OFF -C2[ZP-
8、说明:更改某个表 *qJHoP;
exec sp_changeobjectowner 'tablename','dbo' b5#Jo2C`AJ
9、存储更改全部表 lot;d3}
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch YIs_.CTi
@OldOwner as NVARCHAR(128), b
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@NewOwner as NVARCHAR(128) l>T]Y
AS v"*c\,
DECLARE @Name as NVARCHAR(128) Y
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DECLARE @Owner as NVARCHAR(128) OYfRtfE
DECLARE @OwnerName as NVARCHAR(128) ,T-xuNYC
DECLARE curObject CURSOR FOR
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select 'Name' = name, q26qY5D
'Owner' = user_name(uid) GBTwQYF
from sysobjects 9aYVbq""
where user_name(uid)=@OldOwner k/M{2Po+
order by name :7*9W|e
OPEN curObject H~?7:K
FETCH NEXT FROM curObject INTO @Name, @Owner 5,BvT>zFY
WHILE(@@FETCH_STATUS=0) KP`Pzx
BEGIN <OrQbrWQa
if @Owner=@OldOwner A>frf[fAW
begin q#F+^)DD [
set @OwnerName = @OldOwner + '.' + rtrim(@Name) yuhY )T
exec sp_changeobjectowner @OwnerName, @NewOwner ^e]h\G
end I :8s 3;
-- select @name,@NewOwner,@OldOwner hGI5^!Cq
FETCH NEXT FROM curObject INTO @Name, @Owner L/)eNZ
END FzF#V=9lP
close curObject wjTW{Bg~G
deallocate curObject (ylZ[M&B:
GO 9RC:-d;;_
10、SQL SERVER中直接循环写入数据 5'[yw:P-8
declare @i int i&-g
set @i=1 x=N0H
while @i<30 OX}ZdM!&f
begin %r@:7/
insert into test (userid) values(@i) z`YAOhD*h4
set @i=@i+1 #dFE}!"#`
end (rQ)0g@
小记存储过程中经常用到的本周,本月,本年函数 \Hu?K\SWs
Dateadd(wk,datediff(wk,0,getdate()),-1) aNgJm~K0P
Dateadd(wk,datediff(wk,0,getdate()),6) [7l5p(=
Dateadd(mm,datediff(mm,0,getdate()),0) >}r
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) !
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Dateadd(yy,datediff(yy,0,getdate()),0) u&'&E
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~7H?tp.Dw
上面的SQL代码只是一个时间段 y(j vl|z[
Dateadd(wk,datediff(wk,0,getdate()),-1) AQPzId*z
Dateadd(wk,datediff(wk,0,getdate()),6) 5N907XVu
就是表示本周时间段. }<q=Zq+
下面的SQL的条件部分,就是查询时间段在本周范围内的: 0{u#{_
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) R+Rb[,m
而在存储过程中 ,%KMi-w]q,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) hOe$h,E']
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) (Li)@Cn%