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。 +7nvy^m
?~#[cx
p9mGiK4!
一、基础 J^%E$s
1、说明:创建数据库 ^Jdg%U?
CREATE DATABASE database-name #o9CC)q5G
2、说明:删除数据库 >i.$s
drop database dbname 7!FiPH~kM
3、说明:备份sql server a2i:fz=[
--- 创建 备份数据的 device jsr)
USE master :`"-Jf
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R!WDQGR(2
--- 开始 备份 AN[pjC<
BACKUP DATABASE pubs TO testBack pS7y3(_
4、说明:创建新表 rg]b$tL~
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) @\xEK5 SG
根据已有的表创建新表: }1+2&Ps50
A:create table tab_new like tab_old (使用旧表创建新表) 5J&Gc;[p
B:create table tab_new as select col1,col2... from tab_old definition only qe(C>qjMbG
5、说明:删除新表 XFl&(I4tB
drop table tabname :?m"kh
~
6、说明:增加一个列 zxx9)I@?A
Alter table tabname add column col type A&%7Z^Pp
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。 SkVah:cF-
7、说明:添加主键: Alter table tabname add primary key(col) "{H{-`Ni
说明:删除主键: Alter table tabname drop primary key(col) 4gdXO
8、说明:创建索引:create [unique] index idxname on tabname(col....) ~|ZAS]
删除索引:drop index idxname ,HmGp
注:索引是不可更改的,想更改必须删除重新建。 _%B,^0;C
9、说明:创建视图:create view viewname as select statement 3DB= Xh
删除视图:drop view viewname )hoVB
10、说明:几个简单的基本的sql语句 Us2> 5 :\
选择:select * from table1 where 范围 ,1JQjsR
插入:insert into table1(field1,field2) values(value1,value2) hb/Z{T'
删除:delete from table1 where 范围 /d Ua
更新:update table1 set field1=value1 where 范围 ) .' + {
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *8yC6|wL?
排序:select * from table1 order by field1,field2 [desc] YN:Sn\`D 8
总数:select count as totalcount from table1 M
0RA&
求和:select sum(field1) as sumvalue from table1 B,Tv9(sv
平均:select avg(field1) as avgvalue from table1 ]~f-8!$$R
最大:select max(field1) as maxvalue from table1 TeR bW
最小:select min(field1) as minvalue from table1 !bnnUCTb\
[z=!OFdE
ZC<EPUV(
Sz')1<
11、说明:几个高级查询运算词 R$`&g@P="
@KLX,1K
ncOl}\Q9
A: UNION 运算符 ;:J"- p
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。 mL'A$BR`
B: EXCEPT 运算符 IDh`*F
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。 Q^l!cL| {
C: INTERSECT 运算符 ]6|?H6'/`v
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。 w-v8P`V
注:使用运算词的几个查询结果行必须是一致的。 p<l+js(5|
12、说明:使用外连接 p?P.BU\CR
A、left outer join: T%Zfo7
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。 v~._]f$:
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 s=E6HP@q
B:right outer join: xt`a":lr u
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。 )qFqf<:yc
C:full outer join: ;<E?NBV^
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。 ]rg-=Y k
X(DP=C}v9
"@5{=
二、提升 4mX]JH`UTe
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) L5 Ai
法一:select * into b from a where 1<>1 dWwb}r(ky
法二:select top 0 * into b from a fLSDt(c',
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) d& v 7l
insert into b(a, b, c) select d,e,f from b; r(wtuD23q
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) Zc&pJP+M'U
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 d0zp89BEn
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. UX|3LpFX&I
4、说明:子查询(表名1:a 表名2:b) t0P_$+w.>
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) Y( K`3?A
5、说明:显示文章、提交人和最后回复时间 55y{9.n*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b %.\+j,G7
6、说明:外连接查询(表名1:a 表名2:b) >Kl_948
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c aE"dpYQ
7、说明:在线视图查询(表名1:a ) =i7CF3
select * from (SELECT a,b,c FROM a) T where t.a > 1; 16.?45
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 >Apa^Bp
select * from table1 where time between time1 and time2 [=Nv=d<[p
select a,b,c, from table1 where a not between 数值1 and 数值2 zqI|VH
9、说明:in 的使用方法 7/Bj WU5*
select * from table1 where a [not] in ('值1','值2','值4','值6') I!K-*
AB
10、说明:两张关联表,删除主表中已经在副表中没有的信息 o4z|XhLr
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) $I ,Np)i
11、说明:四表联查问题: g ssEdJ
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 ..... G#uB%:)&0u
12、说明:日程安排提前五分钟提醒 jC?l :m?
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 EF=5[$
u
13、说明:一条sql 语句搞定数据库分页 07ppq?,y
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 puEu)m^
14、说明:前10条记录 ^d(gC%+!u
select top 10 * form table1 where 范围 .O+,1&D5
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.) 8hyXHe
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) XZ(<Mo\v
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 jr-9KxE
(select a from tableA ) except (select a from tableB) except (select a from tableC) 37M,Os1(
17、说明:随机取出10条数据 SVV-zz]3M
select top 10 * from tablename order by newid() mfDt_Iq
18、说明:随机选择记录 0Q
cJ Ek
select newid()
nI+.De~
19、说明:删除重复记录 @|'9nPern
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) L`rrT
20、说明:列出数据库里所有的表名 EgzdRB\Cf
select name from sysobjects where type='U' {sq:vu@NC
21、说明:列出表里的所有的 9]/:B8k
select name from syscolumns where id=object_id('TableName') s,Fts3+
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^}d>2W(
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 L}g#h+GP[
显示结果: wW<u)|>ye
type vender pcs bV#j@MJ~0
电脑 A 1 n1'i!NWt
电脑 A 1 @XcrHnH9
光盘 B 2 1h)K3cC
光盘 A 2 Hbu
:HFJ!
手机 B 3 ;~`/rh
V\
手机 C 3 aouYPxA`
23、说明:初始化表table1 <fMQ#No
TRUNCATE TABLE table1 zP c54>f
24、说明:选择从10到15的记录 @bnw$U`+
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc &{q'$oF
6IJ;od.\b$
r.=.,R
eOZ~p
三、技巧 8N<mV^|}
1、1=1,1=2的使用,在SQL语句组合时用的较多 N\CHIsVm>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, E^pn-rB
如: AOTtAV_e
if @strWhere !='' y4&x`|tv
begin 'CG% PjCO
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere t[G7&ovj
end )$*B
else vP%:\u:{
begin rQpQqBu
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' f&$$*a
end -7Kstc-
我们可以直接写成 +p]@ b
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 'S=eW_ 0/
2、收缩数据库 6&2{V?
W3
--重建索引 ,1vFX$
DBCC REINDEX vEt+^3=
DBCC INDEXDEFRAG r& :v(
--收缩数据和日志 OO,%zwgt
DBCC SHRINKDB #Ny+6XM
DBCC SHRINKFILE CT<z1)#@^
3、压缩数据库 D@@"w+
dbcc shrinkdatabase(dbname) J10&iCr{r*
4、转移数据库给新用户以已存在用户权限 iqsR]mab
exec sp_change_users_login 'update_one','newname','oldname' W3R43>$
go nwDGzC~y<
5、检查备份集 QlH[_Pi
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' C]na4yE8
6、修复数据库 H87k1^}HV
ALTER DATABASE [dvbbs] SET SINGLE_USER G('UF1F
GO v|3mbApv
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK (8/ &
GO !!~r1)zN
ALTER DATABASE [dvbbs] SET MULTI_USER G=kW4rAk
GO NZwi3
7、日志清除 Ov.oyke4
SET NOCOUNT ON O8LIKD_I[
DECLARE @LogicalFileName sysname, D8$4P T0u
@MaxMinutes INT, T@n};,SQ
@NewSize INT /<o?T{z<-
USE tablename -- 要操作的数据库名 FJW,G20L
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 aq(i^d
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Kzwe36O;?
@NewSize = 1 -- 你想设定的日志文件的大小(M) xBqZ:
BQ
-- Setup / initialize U\[b qw
DECLARE @OriginalSize int G^/8^Zi
SELECT @OriginalSize = size )31xl6@
FROM sysfiles C7&L9k~jf
WHERE name = @LogicalFileName &.Yu%=}
SELECT 'Original Size of ' + db_name() + ' LOG is ' + #X?E#^6?E
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + F 9q!Upr_+
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' LftGA7uGJ)
FROM sysfiles H*",'`|-
WHERE name = @LogicalFileName W4nhPH(
CREATE TABLE DummyTrans j& L@L.d
(DummyColumn char (8000) not null) ~O3VX75f
DECLARE @Counter INT, w@,v$4Oi
@StartTime DATETIME, mZjP;6
@TruncLog VARCHAR(255) b$`/f:_
SELECT @StartTime = GETDATE(), RgzzbW
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' e
:@PI(P!
DBCC SHRINKFILE (@LogicalFileName, @NewSize) r[2*K 9
EXEC (@TruncLog) sAF="uB
-- Wrap the log if necessary. F-D$Y?m
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired RXO5pd
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) D\pX@Sx,v[
AND (@OriginalSize * 8 /1024) > @NewSize V7
hO}
BEGIN -- Outer loop. jk%H+<FU`
SELECT @Counter = 0 k<rJm
P{
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 6O*lZNN
BEGIN -- update >.hDt9@4
INSERT DummyTrans VALUES ('Fill Log') M L7 vP
DELETE DummyTrans +\>op,_9I
SELECT @Counter = @Counter + 1 Q>L.
END TA~ZN^xI
EXEC (@TruncLog) k#8E9/t@
END ++=jh6
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Rq|]KAN
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + x l=i_
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Lo=n)cV 1,
FROM sysfiles Z55C4F5v
WHERE name = @LogicalFileName &=wvlI52`
DROP TABLE DummyTrans ]?Q<lMG
SET NOCOUNT OFF =L{-Hu/j
8、说明:更改某个表 pLMaXX~4_
exec sp_changeobjectowner 'tablename','dbo' LQ||7>{eX
9、存储更改全部表 9)4_@rf%
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch KfQR(e9n
@OldOwner as NVARCHAR(128), +Y>oNX1KN
@NewOwner as NVARCHAR(128) ]y"=/Nu-Ja
AS gy"<[N
.?c
DECLARE @Name as NVARCHAR(128) ,!P}Y[|
DECLARE @Owner as NVARCHAR(128) bb-u'"5^]
DECLARE @OwnerName as NVARCHAR(128) }gd'pgN"t
DECLARE curObject CURSOR FOR Z,8t!Y
select 'Name' = name, *lQa^F
'Owner' = user_name(uid) A}_pJH
from sysobjects pxW*kS
where user_name(uid)=@OldOwner J.c
yb
order by name @Z<Z//^k
OPEN curObject XS.*CB_m_
FETCH NEXT FROM curObject INTO @Name, @Owner Ss\FSEN!/
WHILE(@@FETCH_STATUS=0) bP4}a!t+n
BEGIN 8T"kQB.Zv
if @Owner=@OldOwner y-"QY[
begin :kd]n$]
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6LabFX@{&
exec sp_changeobjectowner @OwnerName, @NewOwner 7'|aEH
end LbR'nG{J
-- select @name,@NewOwner,@OldOwner +/hd;s$x
FETCH NEXT FROM curObject INTO @Name, @Owner (?"z!dg c
END B_XX)y %V
close curObject <@Y`RqV +
deallocate curObject eAG)+b
GO vD(:?M
10、SQL SERVER中直接循环写入数据 + 7wMM#z
declare @i int p+b$jKWQ
set @i=1 Q2*
~9QkU
while @i<30 SEH[6W3
begin =uR3|U(.|u
insert into test (userid) values(@i) (]zi;
set @i=@i+1 .=9d3uWJ/
end 4`")aM
小记存储过程中经常用到的本周,本月,本年函数 S,vdd7Y
Dateadd(wk,datediff(wk,0,getdate()),-1) rCb#E}
Dateadd(wk,datediff(wk,0,getdate()),6) 4^:$|\?]
Dateadd(mm,datediff(mm,0,getdate()),0) (ki= s+W-
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) {P)O#
Dateadd(yy,datediff(yy,0,getdate()),0) O9AFQ)u
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 8O[l[5u&
上面的SQL代码只是一个时间段 be?Bf^O>
Dateadd(wk,datediff(wk,0,getdate()),-1) 5gb:,+
Dateadd(wk,datediff(wk,0,getdate()),6) eDvh3Y<D
就是表示本周时间段. `oM'H+
下面的SQL的条件部分,就是查询时间段在本周范围内的: "+Sq}WR
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 0;hn;(V]"
而在存储过程中 QXgfjo
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) d$Y_vX<
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) (;-_j/