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。 Cx"sw
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一、基础 [QTV9
1、说明:创建数据库 CTK;dM'uQ
CREATE DATABASE database-name *Ex|9FCt$
2、说明:删除数据库 1YA% -~
drop database dbname ;S{(]K7i
3、说明:备份sql server '-6~tWC~7
--- 创建 备份数据的 device U*:!W=XN
USE master g0H[*"hj
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'qi}|I
--- 开始 备份 G3]4A&h9v~
BACKUP DATABASE pubs TO testBack E7hhew
4、说明:创建新表 rNM;ZPF#
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ?%86/N>
根据已有的表创建新表: w!CNRtM:~
A:create table tab_new like tab_old (使用旧表创建新表) V~bD)?M
B:create table tab_new as select col1,col2... from tab_old definition only -&f$GUTJ
5、说明:删除新表 R]dg_Da
drop table tabname :,^gj
6、说明:增加一个列 0YzpZW"+
Alter table tabname add column col type )[ ,A_3E
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 v=k$A
7、说明:添加主键: Alter table tabname add primary key(col) ;4a{$Lw~^9
说明:删除主键: Alter table tabname drop primary key(col) YqG7h,F
8、说明:创建索引:create [unique] index idxname on tabname(col....) e)ZUO_Q$
删除索引:drop index idxname Ymgw-NJ;(
注:索引是不可更改的,想更改必须删除重新建。 p<2,=*2
9、说明:创建视图:create view viewname as select statement Q?T]MUY(L
删除视图:drop view viewname E4!Fupkpf
10、说明:几个简单的基本的sql语句 Al'3?
选择:select * from table1 where 范围 'S~5"6r
插入:insert into table1(field1,field2) values(value1,value2) O f#:
删除:delete from table1 where 范围 Qd6F H2Pl
更新:update table1 set field1=value1 where 范围 v:p} B$
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! bcR_E5x$
排序:select * from table1 order by field1,field2 [desc] ':W[ A
总数:select count as totalcount from table1 zL it
求和:select sum(field1) as sumvalue from table1 P4?glh q#
平均:select avg(field1) as avgvalue from table1 ddo#P%sH'
最大:select max(field1) as maxvalue from table1 BHw, 4#F1;
最小:select min(field1) as minvalue from table1 -/k 3a*$/
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11、说明:几个高级查询运算词 t
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A: UNION 运算符 HThcn1u~^b
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。 ~Z+%d9ode
B: EXCEPT 运算符 KG@8RtHsQ
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。 8f7>?BUS,
C: INTERSECT 运算符 |3%8&@ho
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。 7|D +Ihy;
注:使用运算词的几个查询结果行必须是一致的。 {[(h[MW#
12、说明:使用外连接 OTp]Xe/
A、left outer join: \1`O_DF~o
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。 :jx4{V
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 X|[`P<'N<
B:right outer join: iUwzs&frd
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。 IAEAhqp
C:full outer join: nie% eC&U
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。 Wf<LR3
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二、提升 DN/YHSYK
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) a>)f=uS
法一:select * into b from a where 1<>1 w:l"\Tm
法二:select top 0 * into b from a W`&hp6Jq
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \f)#>+X-
insert into b(a, b, c) select d,e,f from b; 6,uX,X5
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) ?8 {"x8W;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 <X5fUU"+U
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 4sM.C9W
4、说明:子查询(表名1:a 表名2:b) h1{3njdr
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) ~v83pu1!2s
5、说明:显示文章、提交人和最后回复时间 kR9-8I{J
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 0Qd:`HF[
6、说明:外连接查询(表名1:a 表名2:b) >{Tm##@,k
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )jC%a6G!
7、说明:在线视图查询(表名1:a ) Ha#>G<;n
select * from (SELECT a,b,c FROM a) T where t.a > 1; WKU=.sY
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 SB7c.H,
select * from table1 where time between time1 and time2 >Se,;cB'/]
select a,b,c, from table1 where a not between 数值1 and 数值2 T)CP2U
9、说明:in 的使用方法 /@Zrq#o
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select * from table1 where a [not] in ('值1','值2','值4','值6') v3qA":(w+(
10、说明:两张关联表,删除主表中已经在副表中没有的信息 b6 M
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) *'X3z@R
11、说明:四表联查问题: v
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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 ..... Wl Sm
12、说明:日程安排提前五分钟提醒 Sc
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ZC}QId
13、说明:一条sql 语句搞定数据库分页
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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 wAd9
14、说明:前10条记录 !by\9
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select top 10 * form table1 where 范围 X jX2]
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.) pmilrZmm]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) \;-|-8Q
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 4X$Qu6#i
(select a from tableA ) except (select a from tableB) except (select a from tableC) -^57oU
17、说明:随机取出10条数据 qw8Rlws%
select top 10 * from tablename order by newid() d| {r5[&
18、说明:随机选择记录 g*"P:n71
select newid() ]:f%l
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19、说明:删除重复记录 6&-(&(_
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) HmwT~
20、说明:列出数据库里所有的表名 ;GhNKPY
select name from sysobjects where type='U' 7)k\{&+P
21、说明:列出表里的所有的 km40qO@3
select name from syscolumns where id=object_id('TableName') XrPfotj1
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。 F>cv<l
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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 @K]|K]cby
显示结果: *:NQ&y*uj
type vender pcs :lzrgsW
电脑 A 1 _? OG1t!
电脑 A 1 JG,%qFlk
光盘 B 2 MWL%
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光盘 A 2 9mFE?J
手机 B 3 Q^(b)>?r;
手机 C 3 Yrn)VV[)h
23、说明:初始化表table1 \15nSB
TRUNCATE TABLE table1 {V-v-f
24、说明:选择从10到15的记录 `p7=t)5k
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc V!dtF,tH
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三、技巧 WT}H>T
1、1=1,1=2的使用,在SQL语句组合时用的较多 42{:G8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ; Hd7*`$
如: 1r7y]FyH$
if @strWhere !='' -tNUMi'
begin !YJs]_Wr
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere T n}s*<=V
end e!r-+.i(
else AvHCO8h|
begin +'@Dz9:>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ^BL"wk
end 2>H24F
我们可以直接写成 FEVlZ<PW3I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Wr5V`sM
2、收缩数据库 {>%&(
--重建索引 ~WN:DXn
DBCC REINDEX BX^tR1
DBCC INDEXDEFRAG sse.*75U
--收缩数据和日志 -)/$M(Pu"
DBCC SHRINKDB FkRo
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DBCC SHRINKFILE -Vhw^T1iV
3、压缩数据库 &=k,?TJO>
dbcc shrinkdatabase(dbname) ilva,WFa^
4、转移数据库给新用户以已存在用户权限 fg{n(TE"8
exec sp_change_users_login 'update_one','newname','oldname' X~i<g?]
go "x /OIf
5、检查备份集 Ip]KPrwp
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' (%:c#;#
6、修复数据库 9<)NvU^-r
ALTER DATABASE [dvbbs] SET SINGLE_USER H$KTo/
GO i@R
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK _\HQvH
GO 'XBFv9&
ALTER DATABASE [dvbbs] SET MULTI_USER 3<zp
GO =6#Eh=7N
7、日志清除 IyPnp&_
SET NOCOUNT ON 2,P^n4~A?w
DECLARE @LogicalFileName sysname, -7(@1@1
@MaxMinutes INT, I,'k>@w{s
@NewSize INT jMDY(mwt
USE tablename -- 要操作的数据库名 <1COZ)
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9RI-Lq`
@MaxMinutes = 10, -- Limit on time allowed to wrap log. HOh!Xcu
@NewSize = 1 -- 你想设定的日志文件的大小(M) CWP2{
-- Setup / initialize I15{)o(8$
DECLARE @OriginalSize int u=_mvN
SELECT @OriginalSize = size t@Nyr&|D
FROM sysfiles Dl8;$~
WHERE name = @LogicalFileName M {Q;:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + qWKAM@
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ]P2"[y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $"&{aa
FROM sysfiles Bng@-#`/
WHERE name = @LogicalFileName yEj^=pw
CREATE TABLE DummyTrans `I5wV/%ib
(DummyColumn char (8000) not null) *C=>X193U
DECLARE @Counter INT, *U\`CXn;
@StartTime DATETIME, ;l-!)0U
@TruncLog VARCHAR(255) &q|K!5[k
SELECT @StartTime = GETDATE(), }XM(:|8J,
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' x7x\Y(@
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 'anG:=
EXEC (@TruncLog) lR6x3C
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-- Wrap the log if necessary. pQ<Y:-`c
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ig':%2V/
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Oh\<VvZuN
AND (@OriginalSize * 8 /1024) > @NewSize A7hVHxNJ-
BEGIN -- Outer loop. g!z&~Z:
SELECT @Counter = 0 1q1jZqno
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) \A6B,|@
BEGIN -- update :'&brp3ii=
INSERT DummyTrans VALUES ('Fill Log') Zdo'{ $
DELETE DummyTrans HuKc9U'7A
SELECT @Counter = @Counter + 1 k/gZ,
END Q7COQ2~K
EXEC (@TruncLog) _1L![-ac
END }:*]aL<7_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + x*&|0n.D
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ziu]'#
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' nSAdCJ;4
FROM sysfiles wtV#l4
WHERE name = @LogicalFileName X<; f
DROP TABLE DummyTrans Jl9k``r*
SET NOCOUNT OFF fku<,SV$O4
8、说明:更改某个表 4^OY
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exec sp_changeobjectowner 'tablename','dbo' %lGfAYEM=
9、存储更改全部表 p >t#@Eu|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch JNUt$h
@OldOwner as NVARCHAR(128), &7wd?)s
@NewOwner as NVARCHAR(128) @\P;W(m.i
AS 6ez<g
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DECLARE @Name as NVARCHAR(128) M$8^91%4B
DECLARE @Owner as NVARCHAR(128) o W Nh@C
DECLARE @OwnerName as NVARCHAR(128) tWa)_y
DECLARE curObject CURSOR FOR :s6o"VkW
select 'Name' = name, X~,aNRy
'Owner' = user_name(uid) _v=SH$O+
from sysobjects Q=20IQp
where user_name(uid)=@OldOwner z4]api(xZ
order by name jc f #6
OPEN curObject EeRX+BM,
FETCH NEXT FROM curObject INTO @Name, @Owner c[1oww
WHILE(@@FETCH_STATUS=0) V0XvJ
BEGIN 6}Y#= }
if @Owner=@OldOwner V2|aN<Sx<
begin :|8M`18lZ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) <r`2)[7N
exec sp_changeobjectowner @OwnerName, @NewOwner zY!j:FT1HY
end FfPar:PHj
-- select @name,@NewOwner,@OldOwner k<{{*
FETCH NEXT FROM curObject INTO @Name, @Owner spPNr
END
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close curObject &,CiM0
deallocate curObject P8)=Kbd
GO o,8TDg
10、SQL SERVER中直接循环写入数据 Q_X.rUL0w
declare @i int &_|#.
set @i=1 )vb*Ef
while @i<30 > eIP.,9
begin YCM]VDx4u1
insert into test (userid) values(@i) #c?j\Y9nz
set @i=@i+1 &&:YVd
end #"\gLr_:m
小记存储过程中经常用到的本周,本月,本年函数 ,+{LYF
Dateadd(wk,datediff(wk,0,getdate()),-1) Pjjewy1}^
Dateadd(wk,datediff(wk,0,getdate()),6) i,4>0o?
Dateadd(mm,datediff(mm,0,getdate()),0) lun\`f 5Q
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) M={V|H0
Dateadd(yy,datediff(yy,0,getdate()),0) `Kr,>sEAM
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ;^%4Q"
上面的SQL代码只是一个时间段 QKN+>X
Dateadd(wk,datediff(wk,0,getdate()),-1) 474SMx$
Dateadd(wk,datediff(wk,0,getdate()),6) #(JNn'fzq
就是表示本周时间段. 4 k _vdz
下面的SQL的条件部分,就是查询时间段在本周范围内的: .QJ5sgmh
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) c~uKsU
而在存储过程中 4f'V8|QM{
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Y+*0~xm4
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) O-I[igNl