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。 ;n\= R 5.
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一、基础 mAk{"65V
1、说明:创建数据库 .qk]$LJF7
CREATE DATABASE database-name T5Dw0Y6u,
2、说明:删除数据库 %+ZJhHT
drop database dbname $,xnU.n
3、说明:备份sql server IlX$YOf4
--- 创建 备份数据的 device |^28\sm2e
USE master r%DFve:%
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Bx[rC
--- 开始 备份 %AOIKK5
BACKUP DATABASE pubs TO testBack 8G>>i)Sbg
4、说明:创建新表 ~j#~\Ir
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) V|)>{Xdn
根据已有的表创建新表: ?S?2 0
A:create table tab_new like tab_old (使用旧表创建新表) }HEvr)v9
B:create table tab_new as select col1,col2... from tab_old definition only >zkRcm
5、说明:删除新表 Ifk#/d
drop table tabname "m{,~'x
6、说明:增加一个列 7VK}Dy/Vvn
Alter table tabname add column col type 4'KOpl
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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。 [P|[vWO
7、说明:添加主键: Alter table tabname add primary key(col) 1_$xSrwcF
说明:删除主键: Alter table tabname drop primary key(col) I8OD$`~*U6
8、说明:创建索引:create [unique] index idxname on tabname(col....) uS&|"*pR
删除索引:drop index idxname /yLZ/<WN
注:索引是不可更改的,想更改必须删除重新建。 6 \B0^
9、说明:创建视图:create view viewname as select statement @DW[Z`X
删除视图:drop view viewname 2cu#lMq
10、说明:几个简单的基本的sql语句 HE<1v@jW
选择:select * from table1 where 范围 ,:+dg(\r
插入:insert into table1(field1,field2) values(value1,value2) Ld^GV
删除:delete from table1 where 范围 ]4+s$rG
更新:update table1 set field1=value1 where 范围 PL{Q!QJK'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 74<!&t
排序:select * from table1 order by field1,field2 [desc] PNW \*;j
总数:select count as totalcount from table1 7^}Ll@
求和:select sum(field1) as sumvalue from table1 'gQidf
平均:select avg(field1) as avgvalue from table1 EL3|u64GO
最大:select max(field1) as maxvalue from table1 @v\*AYr'M
最小:select min(field1) as minvalue from table1 q.Nweu!jQ
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11、说明:几个高级查询运算词 R~bC,`Bh
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A: UNION 运算符 )hwV`2>l
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 p8wyEHB
B: EXCEPT 运算符 2tayP@$
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。 \b[9ebME
C: INTERSECT 运算符 @eqeN9e
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。 hzI*{
注:使用运算词的几个查询结果行必须是一致的。 )o!XWh
12、说明:使用外连接 zb6ju]2
A、left outer join: O7']
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。 @{h?+
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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 &iN--~}!$
B:right outer join: 79zJ\B_
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。 wV?,Z!\Z
C:full outer join: 3M5#4n\v$
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。 GFSt<k)
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二、提升 M(|
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) S{',QO*D6
法一:select * into b from a where 1<>1 BiE08,nj
法二:select top 0 * into b from a AvR2_
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) '2hbJk
insert into b(a, b, c) select d,e,f from b; >Ps7I
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) t+CWeCp,
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 NGYyn`Lx
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. h5
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4、说明:子查询(表名1:a 表名2:b) !#wd Ve_(
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) IB.yU,v
5、说明:显示文章、提交人和最后回复时间 F2(q>#<_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b v;{{ y-
6、说明:外连接查询(表名1:a 表名2:b) ctQbp~-
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c DOm[*1@^
7、说明:在线视图查询(表名1:a ) 3+MB5T
select * from (SELECT a,b,c FROM a) T where t.a > 1; `ir3YnT+
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 Ql?^
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select * from table1 where time between time1 and time2 y0v]N
select a,b,c, from table1 where a not between 数值1 and 数值2 Oc9#e+_&
9、说明:in 的使用方法 Ct$82J
select * from table1 where a [not] in ('值1','值2','值4','值6') wHz?#MW 3L
10、说明:两张关联表,删除主表中已经在副表中没有的信息 /E wGW
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) {>0V[c[~
11、说明:四表联查问题: "Clz'J]{
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 8l/[(] &
12、说明:日程安排提前五分钟提醒 1|,Pq9
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %u?HF4S'
13、说明:一条sql 语句搞定数据库分页 G@S&1=nj3
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 '#\D]5
14、说明:前10条记录 K|W^l\Lt
select top 10 * form table1 where 范围 SM[{BH<
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) tXF]t
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) %;`>`j5
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 p]W+eT
(select a from tableA ) except (select a from tableB) except (select a from tableC) 3l!NG=R
17、说明:随机取出10条数据 l#3($QV,
select top 10 * from tablename order by newid() s(ROgCO
18、说明:随机选择记录 >=ot8%.!,B
select newid() 2k7bK6=nm
19、说明:删除重复记录 ~7q uTp)
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) HU
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20、说明:列出数据库里所有的表名 (.K\Jg'Y6j
select name from sysobjects where type='U' x)5V.q
21、说明:列出表里的所有的 eR']#Q46{T
select name from syscolumns where id=object_id('TableName') B\j~)vg
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。 '(@YK4_M
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 hJ%1
显示结果: h
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type vender pcs (J:dK=O@Z
电脑 A 1 -237Lx$/
电脑 A 1 $%2_{m_K:p
光盘 B 2 h~HB0^|
光盘 A 2 OVoO6F]
手机 B 3 L^9HH)Jc
手机 C 3 k/Mp6<?C:
23、说明:初始化表table1 ~M?|Vn
TRUNCATE TABLE table1 O^{1RV3:,T
24、说明:选择从10到15的记录 t7#lsd`_
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc WbjF]b\
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三、技巧 lpQP"%q
1、1=1,1=2的使用,在SQL语句组合时用的较多 l_FGZ!7
"where 1=1" 是表示选择全部 "where 1=2"全部不选, a,'Cyv">
如: \Z5+$Ij
if @strWhere !='' )&NAs
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere :x>T}C<Y
end #Olg(:\
else e]W0xC-
begin ?z` MPdO
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :jNYP{Br
end 4yV].2#rl"
我们可以直接写成 ;cP8 ?U
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere C;1PsSE+A
2、收缩数据库 u,i]a#K
--重建索引 4~?2wvz G4
DBCC REINDEX #JNy
DBCC INDEXDEFRAG gzfb zt}?
--收缩数据和日志 -R+zeu(e'
DBCC SHRINKDB ;'kI/(;;C
DBCC SHRINKFILE T@+ClZi
3、压缩数据库 (*^DN{5
dbcc shrinkdatabase(dbname) +!>LY
4、转移数据库给新用户以已存在用户权限 dBEIMn@
exec sp_change_users_login 'update_one','newname','oldname' MB$a82bY
go '%4P;HO
5、检查备份集 vgPUIxB@
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' D(Ix!G/
6、修复数据库 Vb6K:ZnF
ALTER DATABASE [dvbbs] SET SINGLE_USER #;j9}N
GO T`L}[?w
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 4_Rdp`x#J
GO n`5WXpz4;
ALTER DATABASE [dvbbs] SET MULTI_USER w-FnE}"l
GO ySX/=T:<;
7、日志清除 XSD%t8<LO
SET NOCOUNT ON IvU{Xm"qB
DECLARE @LogicalFileName sysname, N)OCSeh
@MaxMinutes INT, UOI^c
@NewSize INT [STje8+V
USE tablename -- 要操作的数据库名 1t~({Pl<>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 =3+L#P=i9
@MaxMinutes = 10, -- Limit on time allowed to wrap log. l:e9y $_)
@NewSize = 1 -- 你想设定的日志文件的大小(M) \XH@b6{
-- Setup / initialize VyZV(k
DECLARE @OriginalSize int +t\^(SJ6
SELECT @OriginalSize = size XI}I.M
FROM sysfiles mY2:m(9"5
WHERE name = @LogicalFileName Du_$C[
SELECT 'Original Size of ' + db_name() + ' LOG is ' + v4<j
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Zw=G@4xoU
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' mx tgb$*
FROM sysfiles Lt<oi8'N
WHERE name = @LogicalFileName -{x(`9H;
CREATE TABLE DummyTrans gA
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(DummyColumn char (8000) not null) E2:D(7(;l
DECLARE @Counter INT, vo;5f[>4i
@StartTime DATETIME, `7B14:\A
@TruncLog VARCHAR(255) fEiJ~&{&
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' N du7nKG
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Y^eX@dEFR
EXEC (@TruncLog) u~Lu<3v
-- Wrap the log if necessary. x`2pr
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired x70N8TQ_gK
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) -uR{X G. D
AND (@OriginalSize * 8 /1024) > @NewSize mTd<2Hy
BEGIN -- Outer loop. #eEvF
SELECT @Counter = 0 g~R/3cm4
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Uz>Yn&{y6
BEGIN -- update Z[;#|$J
INSERT DummyTrans VALUES ('Fill Log') *PcVSEP/0
DELETE DummyTrans -Op@y2+c
SELECT @Counter = @Counter + 1 ABiC9[Q0
END j;0ih_Z@4W
EXEC (@TruncLog) iPFL"v<#J
END M7p8^NL
SELECT 'Final Size of ' + db_name() + ' LOG is ' + wO.B~`y
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + \9jpCNdJ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' PJwEA
FROM sysfiles .HD ebi
WHERE name = @LogicalFileName a(Sv,@/
DROP TABLE DummyTrans d<Dn9,G
SET NOCOUNT OFF Lw*1 .~
8、说明:更改某个表 .HOY q
exec sp_changeobjectowner 'tablename','dbo' BD4"pcr
9、存储更改全部表 MgP{W=h2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 0~i q G
@OldOwner as NVARCHAR(128), e[p^p!a
@NewOwner as NVARCHAR(128) W9jNUZVXE#
AS ORtg>az\%
DECLARE @Name as NVARCHAR(128) =F[lg?g
DECLARE @Owner as NVARCHAR(128) Nh :JU?h
DECLARE @OwnerName as NVARCHAR(128) JJNmpUJ
DECLARE curObject CURSOR FOR 5=.7\#D
select 'Name' = name, ahoh9iJ
'Owner' = user_name(uid) cUVTRWV
from sysobjects }wG|%Y#+r
where user_name(uid)=@OldOwner g5<ZS3tQ
order by name
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OPEN curObject |$ w0+bV*
FETCH NEXT FROM curObject INTO @Name, @Owner 0$?qoS
WHILE(@@FETCH_STATUS=0) B{4"$Mi
BEGIN xO gq-@`
if @Owner=@OldOwner (WkTQRcN,
begin JchA=n
set @OwnerName = @OldOwner + '.' + rtrim(@Name) AG=9b
exec sp_changeobjectowner @OwnerName, @NewOwner _X?y,#
end z=%IcSx;
-- select @name,@NewOwner,@OldOwner &08Tns"
FETCH NEXT FROM curObject INTO @Name, @Owner 8tC + lc
END 5D-BIPn=JV
close curObject e18T(g_i
deallocate curObject W&LBh%"g
GO gpsrw>nw
10、SQL SERVER中直接循环写入数据 B~4mk
declare @i int ~q5-9{ma
set @i=1 -MUQ\pZ
while @i<30 Ol_/uy1r[
begin
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insert into test (userid) values(@i) "1CGO@AXS
set @i=@i+1 R>` ih&,)
end 2}>go^#O/w
小记存储过程中经常用到的本周,本月,本年函数 }o{!}g9
Dateadd(wk,datediff(wk,0,getdate()),-1) .8%vd
Dateadd(wk,datediff(wk,0,getdate()),6) ?^ eJ:
Dateadd(mm,datediff(mm,0,getdate()),0) f5N<3 m=
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) =X<)5IS3
Dateadd(yy,datediff(yy,0,getdate()),0) M Yu?&}%^
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) WY3_7k8u
上面的SQL代码只是一个时间段 U0zW9jB
Dateadd(wk,datediff(wk,0,getdate()),-1) &F9OZMK=
Dateadd(wk,datediff(wk,0,getdate()),6)
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就是表示本周时间段. V9gVn?O0
下面的SQL的条件部分,就是查询时间段在本周范围内的: @eA %(C
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) mnQal>0~
而在存储过程中 )m)h/_
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) O} (E(v
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |#!eMJ&0