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。 {H)hoAenA
!Q15qvRS
*DC/O(
0
一、基础 ]& ckq
1、说明:创建数据库
vxTn
CREATE DATABASE database-name _:=\h5}8
2、说明:删除数据库 HbI{Xf[6LP
drop database dbname ,;Wm>V)o
3、说明:备份sql server vt2.
i$u
--- 创建 备份数据的 device G<D8a2q
USE master hTzj{}w
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' R[j? \#
--- 开始 备份 Z4Dx:m-
BACKUP DATABASE pubs TO testBack fmj}NV&ma
4、说明:创建新表 #IvKI+"
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 'ia-h7QWS
根据已有的表创建新表: R20 .dA_N
A:create table tab_new like tab_old (使用旧表创建新表) 7@\.()
B:create table tab_new as select col1,col2... from tab_old definition only "Zh,;)hS
5、说明:删除新表 L"vrX
drop table tabname _ia&|#n
6、说明:增加一个列 $f0u
Alter table tabname add column col type 19qHWU^0V
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 @n?"*B
7、说明:添加主键: Alter table tabname add primary key(col) &qG/\
说明:删除主键: Alter table tabname drop primary key(col) z$R&u=J
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;mQ|+|F6X
删除索引:drop index idxname ))f@9m
注:索引是不可更改的,想更改必须删除重新建。 g:ky;-G8b
9、说明:创建视图:create view viewname as select statement -Pp{aFe
删除视图:drop view viewname pxgf%P<7
10、说明:几个简单的基本的sql语句 4@3 \Ihv
选择:select * from table1 where 范围 c-(RjQ~M5
插入:insert into table1(field1,field2) values(value1,value2) N,-C+r5}<4
删除:delete from table1 where 范围 #p>&|I
更新:update table1 set field1=value1 where 范围 K~,!IU_QG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! iYgVSVNg
排序:select * from table1 order by field1,field2 [desc] l`zhKj
总数:select count as totalcount from table1 x\8g ICf
求和:select sum(field1) as sumvalue from table1 4X]/8%]V
平均:select avg(field1) as avgvalue from table1 M$%ON>Kq
最大:select max(field1) as maxvalue from table1 9dNkKMc@
最小:select min(field1) as minvalue from table1 SNOc1c<~
Gg9s.]W
PiM(QR
i@nRZ$ K
11、说明:几个高级查询运算词 2|lR@L sr
zPp22
v4s4D1}
A: UNION 运算符 v1~l=^4&
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。 H`)eT6:|/
B: EXCEPT 运算符 ocWl]h].
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。 a<q9~QS
C: INTERSECT 运算符 ,--#3+]XU
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;q0'_G
注:使用运算词的几个查询结果行必须是一致的。 eLPtdP5k
12、说明:使用外连接 aOGoJCt
C
A、left outer join: p-{ 4 $W
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 F\xIVY
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c S1Y,5,}
B:right outer join: T$"~Vu
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。 fYy w2"
C:full outer join: pLCj"D).M
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。 gi,7X\`KQ
*sU,waX
>;,23X
二、提升 \99'#]\_/E
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !7I07~&1
法一:select * into b from a where 1<>1 G<-KwGy,D
法二:select top 0 * into b from a 4AJT)I.
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) JseKqJ?g
insert into b(a, b, c) select d,e,f from b; aUZ?Ue9l>2
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) [;,E cw^
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 fVgK6?<8^
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. }Y.YJXum
4、说明:子查询(表名1:a 表名2:b) Db|JR
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) WUie`p
5、说明:显示文章、提交人和最后回复时间 [k\VUg:P
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b sx=1pnP9`
6、说明:外连接查询(表名1:a 表名2:b) PWl;pBo
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 'uL$j=vB
7、说明:在线视图查询(表名1:a ) yg'CL/P
select * from (SELECT a,b,c FROM a) T where t.a > 1; W`9{RZ'
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 9`/e=RL
select * from table1 where time between time1 and time2
gPB=Z!
select a,b,c, from table1 where a not between 数值1 and 数值2 8iY.!.G#|
9、说明:in 的使用方法 *Ci&1Mu^Z
select * from table1 where a [not] in ('值1','值2','值4','值6') Al*=%nY
10、说明:两张关联表,删除主表中已经在副表中没有的信息 j1g$LAe
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ffL]_E
11、说明:四表联查问题: 59D'*!l-
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 ..... !Z2h?..O
12、说明:日程安排提前五分钟提醒 rBmW%Gv
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 zqdkt `
13、说明:一条sql 语句搞定数据库分页 drjNK!XL@
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 ^2Cqy%x-
14、说明:前10条记录 =<H ekiYM
select top 10 * form table1 where 范围 G`%rnu
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.) @JhkUGG]p
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )J @[8 x`
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 uo]\L^j
(select a from tableA ) except (select a from tableB) except (select a from tableC) \Qah*1
17、说明:随机取出10条数据 7=fNvES2
select top 10 * from tablename order by newid() &77J,\C$:
18、说明:随机选择记录 h\@X!Z,
select newid() jbS@6 *_
19、说明:删除重复记录 [rcM32
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) nw/g[/<;
20、说明:列出数据库里所有的表名 4K:Aqqhds
select name from sysobjects where type='U' Kn$E{ F\
21、说明:列出表里的所有的 z. hq2v
select name from syscolumns where id=object_id('TableName') -
i2^ eZl
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。 &&<l}E
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 2
oL$I(83
显示结果: I_8 n>\u
type vender pcs 5Xxdm-0
电脑 A 1 E.m2- P;4
电脑 A 1 \kyoA
Z
光盘 B 2 \\R<HuTY
光盘 A 2 WNjG/U
手机 B 3 }KUK|p5
手机 C 3 C3=0st$
23、说明:初始化表table1 <Af&Q0J
TRUNCATE TABLE table1 F7C+uGTs
24、说明:选择从10到15的记录 Z"Lr5'}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc l=P)$O|=w
= =pQ
V[
Xl<*Fn?
wGs'qL"z
三、技巧 ~FAk4z=Ed
1、1=1,1=2的使用,在SQL语句组合时用的较多 t
4M-;y
"where 1=1" 是表示选择全部 "where 1=2"全部不选, #G(ivRo
如: wU'+4N".
if @strWhere !='' +pK 35u
begin FU*q9s `
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere fS'` 9
end \ 6taC
else {l/`m.Z
begin ODRy
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' >u0XV "g$
end ]!"7k_
我们可以直接写成 4!ZT_q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere >@G"*le*)
2、收缩数据库 "tJ[M
--重建索引 t}}Ti$$>
DBCC REINDEX \O~/^ Y3U!
DBCC INDEXDEFRAG #d<"Ub
--收缩数据和日志 1\lZ&KX$i
DBCC SHRINKDB pR2U&OA
DBCC SHRINKFILE wLI1qoDM
3、压缩数据库 %'. x vC
dbcc shrinkdatabase(dbname) NuF?:L[
4、转移数据库给新用户以已存在用户权限 ^u90N>Dvq
exec sp_change_users_login 'update_one','newname','oldname' *e:I*L
go Fku<|1}&y
5、检查备份集 7N OF^/nU
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' /i_FA]Go
6、修复数据库 _ A{F2M
ALTER DATABASE [dvbbs] SET SINGLE_USER !%(kMN
GO 9RSviIi$
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK EcytNYn
GO I%Z=O=
ALTER DATABASE [dvbbs] SET MULTI_USER t5 ^hZZ
GO sc-h O9~k
7、日志清除 @Wm:Rz
SET NOCOUNT ON NTK9`#SA
DECLARE @LogicalFileName sysname, =%I;Y& K
@MaxMinutes INT, mss.\
@NewSize INT S&l [z,
USE tablename -- 要操作的数据库名 %<O~eXY
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 O\=Zo9(NHF
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1x##b[LC
@NewSize = 1 -- 你想设定的日志文件的大小(M) /Wl8Jf7'
-- Setup / initialize rOYYZ)Qw
DECLARE @OriginalSize int plr3&T~,&S
SELECT @OriginalSize = size kbH@h2Ww
FROM sysfiles L|b[6[XTHL
WHERE name = @LogicalFileName 2*gB ~Jn4
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 3;uLBuZOCN
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ]i1OssV~>
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' S5H}
FROM sysfiles h~._R6y
WHERE name = @LogicalFileName I;?PDhDb
CREATE TABLE DummyTrans nHF~a?|FT
(DummyColumn char (8000) not null) hVFZQJ?cv
DECLARE @Counter INT, 211T}a
@StartTime DATETIME, {5ehm
@TruncLog VARCHAR(255) B=r+
m;(
SELECT @StartTime = GETDATE(), |{,c2Ck:N
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Dequ'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) uB6Mjdp6
EXEC (@TruncLog) ?djH!
-- Wrap the log if necessary. I^n,v )
8
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired tblduiN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) #
eFdu
AND (@OriginalSize * 8 /1024) > @NewSize f\RTO63|O
BEGIN -- Outer loop. "?iyvzo
SELECT @Counter = 0 )@tHS-Jf
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -~_|ZnuM9
BEGIN -- update y>T>
INSERT DummyTrans VALUES ('Fill Log') s`v$r,N0
DELETE DummyTrans y
La E]
SELECT @Counter = @Counter + 1 MU '-
END ,@M<O!%Cs
EXEC (@TruncLog) pnL[FMc
END Ll#W:~
SELECT 'Final Size of ' + db_name() + ' LOG is ' + jWvi%Iqi
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + xd"+ &YT
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N<Ym&$xR
FROM sysfiles L0{[L
WHERE name = @LogicalFileName ) 3f\H
DROP TABLE DummyTrans w|0:0Rc~u
SET NOCOUNT OFF /Q89 y[
8、说明:更改某个表 QTN24 q4
exec sp_changeobjectowner 'tablename','dbo' [P }mDX
9、存储更改全部表 7&]|c?([4
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch m9DTz$S.
@OldOwner as NVARCHAR(128), v<(+ l)Ln
@NewOwner as NVARCHAR(128) $|[N3
AS k#/cdK!K
DECLARE @Name as NVARCHAR(128) +`$$^x
DECLARE @Owner as NVARCHAR(128) ])?h~
DECLARE @OwnerName as NVARCHAR(128) yVK l%GO
DECLARE curObject CURSOR FOR GlC (uhCpV
select 'Name' = name, *L Y6hph"
'Owner' = user_name(uid) 7j#Ix$Ur
from sysobjects *p\fb7Pu_3
where user_name(uid)=@OldOwner !4Sd ^"
order by name zITxJx
OPEN curObject i]@k'2N
FETCH NEXT FROM curObject INTO @Name, @Owner NweGK
WHILE(@@FETCH_STATUS=0) #3RElI
BEGIN (WY9EJ<s,
if @Owner=@OldOwner COBjJ3
begin /3sX>Rj
set @OwnerName = @OldOwner + '.' + rtrim(@Name) \;Q!}_ K
exec sp_changeobjectowner @OwnerName, @NewOwner 6rCUq
end >r}?v3QW
-- select @name,@NewOwner,@OldOwner .*W7Z8!e
FETCH NEXT FROM curObject INTO @Name, @Owner >@-.rkd(
END
J!3;\
close curObject hl)jE
06
deallocate curObject uc]5p(9Hb
GO _[l&{,
10、SQL SERVER中直接循环写入数据 Z>X]'q03
declare @i int ]F;1 l3I-
set @i=1 \F+".X#jh
while @i<30 v:9'k~4)
begin LN5q_ZvR
insert into test (userid) values(@i) ~6QV?j
set @i=@i+1 OJM2t`}_t
end 9q[[
,R
小记存储过程中经常用到的本周,本月,本年函数 B|M@o^Tf
Dateadd(wk,datediff(wk,0,getdate()),-1) B
T
{cTj0W
Dateadd(wk,datediff(wk,0,getdate()),6) _~P&8
Dateadd(mm,datediff(mm,0,getdate()),0) hKnV=Ha(
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) !tx.2m*5
Dateadd(yy,datediff(yy,0,getdate()),0) *&+zI$u(
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) WYcZD_
上面的SQL代码只是一个时间段 (hKjr1s
Dateadd(wk,datediff(wk,0,getdate()),-1) )Q}Q -Zt
Dateadd(wk,datediff(wk,0,getdate()),6) R,OT\FQ<
就是表示本周时间段. \TDn q!)?
下面的SQL的条件部分,就是查询时间段在本周范围内的: }6{00er
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8f%OPcr&
而在存储过程中 /V]i3ac
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) p=i6~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Xw|-v$'y