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。 *&>1A A
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一、基础 3A]Y=gfa
1、说明:创建数据库 zT0rvz1),M
CREATE DATABASE database-name "8VCXD
2、说明:删除数据库 l%lkDh!$"
drop database dbname dc_^
3、说明:备份sql server v')Fq[H
--- 创建 备份数据的 device |UM':Ec
USE master InMeD[*^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \uQB%yMoz
--- 开始 备份 :h?"0,
BACKUP DATABASE pubs TO testBack D0=D8P}H:
4、说明:创建新表 r#rQ3&Vn
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) T30!'F(*,
根据已有的表创建新表: * 4GJ<
A:create table tab_new like tab_old (使用旧表创建新表) "ji4xy
B:create table tab_new as select col1,col2... from tab_old definition only #ldNWwvRGj
5、说明:删除新表 0)-l9V
drop table tabname -DhF> 4f
6、说明:增加一个列 <r.f ?chf
Alter table tabname add column col type ( }5k"9Z
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 nK1XJp
7、说明:添加主键: Alter table tabname add primary key(col) :x]gTZ?
说明:删除主键: Alter table tabname drop primary key(col) <6U{I '
8、说明:创建索引:create [unique] index idxname on tabname(col....) Qs8iu`'
删除索引:drop index idxname P~iu|j
注:索引是不可更改的,想更改必须删除重新建。 :gVz}/C.@
9、说明:创建视图:create view viewname as select statement pNr3u
删除视图:drop view viewname lQ!ukl)
10、说明:几个简单的基本的sql语句 gvYa&N
选择:select * from table1 where 范围 =:v\}/
插入:insert into table1(field1,field2) values(value1,value2) @~'c(+<3
删除:delete from table1 where 范围 TZi%,yK
更新:update table1 set field1=value1 where 范围 ~UB@IV6O
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! `;*%5WD%
排序:select * from table1 order by field1,field2 [desc] _sbZyL
总数:select count as totalcount from table1 S%-L!V ,
求和:select sum(field1) as sumvalue from table1 KnbT2
平均:select avg(field1) as avgvalue from table1 q0jzng
最大:select max(field1) as maxvalue from table1 cG6Q$
最小:select min(field1) as minvalue from table1 V/$qD
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11、说明:几个高级查询运算词 ;"
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A: UNION 运算符 0XSZ3dY&+
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 &9, 6<bToP
B: EXCEPT 运算符 b)(#/}jMkD
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 XB UO
C: INTERSECT 运算符 M/:kh,3
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 fBS;~;l
注:使用运算词的几个查询结果行必须是一致的。 E@hvO%
12、说明:使用外连接 Q?L-6]pg
A、left outer join: fxXZ^#2wX
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ^;$a_eR
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 4&!`Yi_1L
B:right outer join: bqFGDmu6'
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。 66fvS}x
C:full outer join: s[nXr
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。 BC%t[H} >R
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二、提升 4(& W>E
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) "639oB
法一:select * into b from a where 1<>1 }ARWR.7Cc
法二:select top 0 * into b from a #n]js7
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 'D-eFJ5
insert into b(a, b, c) select d,e,f from b; NcZ6!wWdE
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) !3v!BJ#+,&
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }?$d~]t)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. y+_GL=J
4、说明:子查询(表名1:a 表名2:b) tcSn`+Bu_`
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) h<4WY#Y
5、说明:显示文章、提交人和最后回复时间 SWY?0Pu
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b QB'-`GwL
6、说明:外连接查询(表名1:a 表名2:b) :-xp'_\L
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c hdQ[=PH)
7、说明:在线视图查询(表名1:a ) 5 .0BaVwi
select * from (SELECT a,b,c FROM a) T where t.a > 1; =PP]LDlJs
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 0yfmQ=,X
select * from table1 where time between time1 and time2 &7,Kv0j}
select a,b,c, from table1 where a not between 数值1 and 数值2 CSRcTxH
9、说明:in 的使用方法 z,87;4-
select * from table1 where a [not] in ('值1','值2','值4','值6') MM3X!
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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 uwsGtgd&
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Z`o}xV
11、说明:四表联查问题: [~`;
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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 ..... A 7'dD$9
12、说明:日程安排提前五分钟提醒 J)oa:Q
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 cT`x,2
13、说明:一条sql 语句搞定数据库分页 )3=oS1p
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 IfF<8~~E
14、说明:前10条记录 -d[9mS
select top 10 * form table1 where 范围 6{8qATLR
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) q*{i /=~
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [a53H$`\5
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 ZtlF]k:MV
(select a from tableA ) except (select a from tableB) except (select a from tableC) 67+ K
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17、说明:随机取出10条数据 gs_"H
select top 10 * from tablename order by newid() Os?G_ziIB
18、说明:随机选择记录 2/PaXI/Z
select newid() ~j^HDHY@
19、说明:删除重复记录 T|GRkxd,E3
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [( BA:x1
20、说明:列出数据库里所有的表名 Nj1vB;4Nx
select name from sysobjects where type='U' <8|vj2d2
21、说明:列出表里的所有的 br.jj
select name from syscolumns where id=object_id('TableName') { .B^
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。 bqJL@!T
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 y-cRqIM
显示结果: W(E!:
type vender pcs f]^(|*6
电脑 A 1 S7P](F=n#
电脑 A 1 ]7^OTrZ N
光盘 B 2 %0YwaxXPn7
光盘 A 2 p~J`}>yo
手机 B 3 w")VcAq
手机 C 3 _&FcHwRy
23、说明:初始化表table1 C8}ujC
TRUNCATE TABLE table1 =O?<WJoK
24、说明:选择从10到15的记录 w}zl=w{G
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc N8m|Y]^H#
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三、技巧 yBXdj`bV
1、1=1,1=2的使用,在SQL语句组合时用的较多 ^:5;H=.
"where 1=1" 是表示选择全部 "where 1=2"全部不选, %a<N[H3NV@
如: SouPk/-B80
if @strWhere !='' @aN<nd`q)
begin n7i;^=9mM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere IFlDw}M!9
end 3o9`Ko0
else / *Z(;-
begin )?^0<l#s
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' )TnxsFC
end 0$b)@
我们可以直接写成 {-2I^Ym 5i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ~=aD*v<3d
2、收缩数据库 'IY?7+[
--重建索引 <_=a1x
DBCC REINDEX P#\L6EO.
DBCC INDEXDEFRAG -^=gQ7f9
--收缩数据和日志 ~b+4rYNxU_
DBCC SHRINKDB 4.$<o/M
DBCC SHRINKFILE HUuL3lYka
3、压缩数据库 ?k<i e2
dbcc shrinkdatabase(dbname) tH,}_Bp
4、转移数据库给新用户以已存在用户权限 v
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exec sp_change_users_login 'update_one','newname','oldname' *.K+"WS%
go DlC`GZEtqh
5、检查备份集 YQ}Rg5o
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ogbLs)&+a
6、修复数据库 /@gD
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ALTER DATABASE [dvbbs] SET SINGLE_USER |G&<@8O
GO \\AufAkJ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;f#%0W{":
GO @Iia>G@Rz
ALTER DATABASE [dvbbs] SET MULTI_USER ~cbq5||
GO FUkO$jnO
7、日志清除 OE]zC
SET NOCOUNT ON NVU @m+m~
DECLARE @LogicalFileName sysname, 7pH(_-TF
@MaxMinutes INT, |&`NB|
@NewSize INT }]$%aMxy T
USE tablename -- 要操作的数据库名 AWsO?|YT
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 qX^#fk7]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. N%v}$58Z
@NewSize = 1 -- 你想设定的日志文件的大小(M) mjO4GpG3
-- Setup / initialize .xS3,O_[
DECLARE @OriginalSize int 0%+S@_|
SELECT @OriginalSize = size dnTB$8&
FROM sysfiles #56}RV1
WHERE name = @LogicalFileName Eqc&iS~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Qu,W3d
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Y!c
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ``kiAKMy
FROM sysfiles h}k)7
WHERE name = @LogicalFileName Eo
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CREATE TABLE DummyTrans f=]+\0MQ
(DummyColumn char (8000) not null) Pc#8~t}2
DECLARE @Counter INT, Ox7v*[x'
@StartTime DATETIME, "aIiW VQ
@TruncLog VARCHAR(255) td%]l1
SELECT @StartTime = GETDATE(), JV(qTb W
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' De%WT:v
DBCC SHRINKFILE (@LogicalFileName, @NewSize) `[3Iz$K=
EXEC (@TruncLog) _U( b
-- Wrap the log if necessary. 3TVp
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired B38_1X7
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) EtvZk9d6h*
AND (@OriginalSize * 8 /1024) > @NewSize vM!lL6T:
BEGIN -- Outer loop. #_0OYL`(mE
SELECT @Counter = 0 (JHzwI8+
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) =>#
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BEGIN -- update 4+e9:r]
INSERT DummyTrans VALUES ('Fill Log') ~XQj0'
DELETE DummyTrans f4YcZyBGv
SELECT @Counter = @Counter + 1 ((&_m9a
END 9g3e( z@
EXEC (@TruncLog) zs|R#?a=
END 0$NcxbM
SELECT 'Final Size of ' + db_name() + ' LOG is ' + S
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Vp{! Ft8>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' A:PQIcR;V
FROM sysfiles 4scY8(1
WHERE name = @LogicalFileName Ss6mN;&D
DROP TABLE DummyTrans (8qD'(@
SET NOCOUNT OFF nJ'FH['
8、说明:更改某个表 aNLRUdc.
exec sp_changeobjectowner 'tablename','dbo' -x)Oo`
9、存储更改全部表 rDFDrviW_
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch *"Yz"PK
@OldOwner as NVARCHAR(128), {U@&hE
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@NewOwner as NVARCHAR(128) T n.Cj5
AS bC*( ,n<'
DECLARE @Name as NVARCHAR(128) q-gp;Fm
DECLARE @Owner as NVARCHAR(128) C#{s[l \]
DECLARE @OwnerName as NVARCHAR(128) \) DJo
DECLARE curObject CURSOR FOR M"# >?6{
select 'Name' = name, [&12`!;j
'Owner' = user_name(uid) ERD( qL.J
from sysobjects Y~z3fd
where user_name(uid)=@OldOwner y"zgpqJ
order by name Wy1#K)LRb
OPEN curObject &/QdG= r +
FETCH NEXT FROM curObject INTO @Name, @Owner -OV:y],-
WHILE(@@FETCH_STATUS=0) RW| LL@r
BEGIN E57:ap)/
if @Owner=@OldOwner D>Ij
begin BkywYCWZ )
set @OwnerName = @OldOwner + '.' + rtrim(@Name) pT3p!/pl3
exec sp_changeobjectowner @OwnerName, @NewOwner %c+`8 wj
end dJyf.VJ
-- select @name,@NewOwner,@OldOwner 7|$cM7_r
FETCH NEXT FROM curObject INTO @Name, @Owner PP/EZ ^]b
END ;MRK*sfw{
close curObject .quui\I3
deallocate curObject {Yq"%n'0
GO mL\_C9k,n
10、SQL SERVER中直接循环写入数据 _cPGS=Ew
declare @i int :
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set @i=1 JF{yhx,+p
while @i<30 $ZnLY uGb
begin BpL7s
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insert into test (userid) values(@i) Y]>!uwn
set @i=@i+1 >4I,9TO
end ]M^k~Xa
小记存储过程中经常用到的本周,本月,本年函数 `N;}Gf-'
Dateadd(wk,datediff(wk,0,getdate()),-1) KmF"Ccc
Dateadd(wk,datediff(wk,0,getdate()),6) w5/`_m!
Dateadd(mm,datediff(mm,0,getdate()),0) $H\[yg>4
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ZiR },F/
Dateadd(yy,datediff(yy,0,getdate()),0) 8+}yf.`
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 8w,+Y]X<P[
上面的SQL代码只是一个时间段 Ih Yso7g
Dateadd(wk,datediff(wk,0,getdate()),-1) KMs[/|HX\
Dateadd(wk,datediff(wk,0,getdate()),6) Hlh`d N
就是表示本周时间段. R'Gka1v
下面的SQL的条件部分,就是查询时间段在本周范围内的: `.oWmBey\
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 2EO WbN}M
而在存储过程中 +\Hh|Uz5
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) vR`#kxSdJ@
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6YErF|