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。 Jny)uo8
P!FEh'.
kByrhK5U
一、基础 #6N+5Yx_[
1、说明:创建数据库 AvrL9D
CREATE DATABASE database-name 'wz\tT ^
2、说明:删除数据库 o=-Vt,2{
drop database dbname b\?7?g
3、说明:备份sql server ljYpMv.>xG
--- 创建 备份数据的 device Tf#2"(!
USE master mWli}j#
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~&DB!6*
--- 开始 备份 0i5y(m&7
BACKUP DATABASE pubs TO testBack bB:r]*_
s]
4、说明:创建新表 fou_/Nrue
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) SE;Tujwhqi
根据已有的表创建新表: {K45~ha9!m
A:create table tab_new like tab_old (使用旧表创建新表) #*Yi4Cn<
B:create table tab_new as select col1,col2... from tab_old definition only Y^f94s:2S
5、说明:删除新表 $!|8g`Tm
drop table tabname jD '
6、说明:增加一个列 JO2ZS6k[
Alter table tabname add column col type 7b&JX'`Mb
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 #+K
Kvk
7、说明:添加主键: Alter table tabname add primary key(col) )D["M$ZA^
说明:删除主键: Alter table tabname drop primary key(col) cBLR#Yu;O5
8、说明:创建索引:create [unique] index idxname on tabname(col....) AXl!cgi
删除索引:drop index idxname j{{~Z M
注:索引是不可更改的,想更改必须删除重新建。 {Ax)[<i
9、说明:创建视图:create view viewname as select statement ^)f{q)to
删除视图:drop view viewname ;-KAUgL2
10、说明:几个简单的基本的sql语句 >d8x<|D
选择:select * from table1 where 范围 PPoI>J
插入:insert into table1(field1,field2) values(value1,value2) G$;]
?g
删除:delete from table1 where 范围 M5GY>3P$c
更新:update table1 set field1=value1 where 范围 t."g\;
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #`jE%ONC
排序:select * from table1 order by field1,field2 [desc] 9Fy\t{ks
总数:select count as totalcount from table1
""1#bs{n
求和:select sum(field1) as sumvalue from table1 bBUbw *DF)
平均:select avg(field1) as avgvalue from table1 hWD !
最大:select max(field1) as maxvalue from table1 1R=)17'O
最小:select min(field1) as minvalue from table1 U1,~bO9
0?lp/|K
~L %Pz0Gg
bZNIxkc[Dh
11、说明:几个高级查询运算词 9wO/?
f^W[;w
E?3 0J3S
A: UNION 运算符 1Pk mg%+
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。 =\~E n5
B: EXCEPT 运算符 r0\cc6
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。 ?EI'^xg
C: INTERSECT 运算符 op hH9D
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。 f._l105.
注:使用运算词的几个查询结果行必须是一致的。 =X-^YG3x
12、说明:使用外连接 P?9nTG
A、left outer join: u0m5JD0/
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。 -VS9`7k
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 C#MFpT
B:right outer join: M{`/f@z(
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。 :s'o~
C:full outer join: q} ]'Q
-
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。 j/)"QiS*?
r<;l{7lY_
&w+;N5}3
二、提升 slU
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 51I|0ly
法一:select * into b from a where 1<>1 W8w3~
法二:select top 0 * into b from a 01U
*_\
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) bTZ>@~$
insert into b(a, b, c) select d,e,f from b; 9$Ig~W)
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 0:Ar|to$m
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;% 2wGT
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. LnP3z5d(
4、说明:子查询(表名1:a 表名2:b) U'tE^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) FH)t:!#
5、说明:显示文章、提交人和最后回复时间 F-_%>KJS
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ;wJ~ha C
6、说明:外连接查询(表名1:a 表名2:b) $o]r]#B+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <,\ `Psa)N
7、说明:在线视图查询(表名1:a ) W7H&R,
select * from (SELECT a,b,c FROM a) T where t.a > 1; P
@zz"~f7
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括
}10\K
select * from table1 where time between time1 and time2 ,Pn-ZF
select a,b,c, from table1 where a not between 数值1 and 数值2 l B1#
9、说明:in 的使用方法 p6`Pp"J_tr
select * from table1 where a [not] in ('值1','值2','值4','值6') z< z*Wz
10、说明:两张关联表,删除主表中已经在副表中没有的信息 0y)}.'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) o4$Ott%Wm
11、说明:四表联查问题: gfi
AK%
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 ..... KX!i\NHz
12、说明:日程安排提前五分钟提醒 6gXIt9B.h$
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 l0I}&,+
13、说明:一条sql 语句搞定数据库分页 vt//)*(.$
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 ujU=JlJ7dl
14、说明:前10条记录 g %f*ofb
select top 10 * form table1 where 范围 &J_Z~^
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.) vu=me?m?(
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) _w 5RK(
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 pgT9hle/
(select a from tableA ) except (select a from tableB) except (select a from tableC) [`d$X^<y;
17、说明:随机取出10条数据 m9Ax\lf
select top 10 * from tablename order by newid() OFA{
KZga
18、说明:随机选择记录
3P1&;
select newid() nSS>\$
19、说明:删除重复记录 P`
#QGZ>
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [r(Qs|
20、说明:列出数据库里所有的表名 r#A_RZ2~@
select name from sysobjects where type='U' #? dUv#
21、说明:列出表里的所有的 z"lqrSJ:
select name from syscolumns where id=object_id('TableName') |'tW=
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 @5WgqB
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type r!7 Y'|
显示结果: 3{KR
{B#L
type vender pcs ['z!{Ez
电脑 A 1 n|Pr/ddL
电脑 A 1 ?>af'o:
光盘 B 2 b/t
光盘 A 2 } ^i b
手机 B 3 -_NC%iN#C
手机 C 3 =VNSiK>F
23、说明:初始化表table1 Y2C9(Zk
U
TRUNCATE TABLE table1 b.s9p7:J
24、说明:选择从10到15的记录 %JtbRs(~q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc mL woi!]m
{Hl[C]25X
TI=h_%mO
QYQtMb,
三、技巧 in<}fAro6
1、1=1,1=2的使用,在SQL语句组合时用的较多 yPV'pT)
"where 1=1" 是表示选择全部 "where 1=2"全部不选, P-CB;\
如: sc W'AJJq
if @strWhere !='' _d@=nK)
begin Rs*vm
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Jic}+X*0
end {^5?)/<
else G/vC~6x
begin !Vheq3"q/
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' RW_q~bA9
end
1S0pd-i
我们可以直接写成 *XbI#L%>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere w(j^ccPD
2、收缩数据库 ,`32!i
--重建索引 GMW,*if8p
DBCC REINDEX N
L'R\R
DBCC INDEXDEFRAG Gs
dnf 7
--收缩数据和日志 Rrg8{DZhv
DBCC SHRINKDB (vc|7DX M
DBCC SHRINKFILE iEIg:
3、压缩数据库 8!mc@$Z
dbcc shrinkdatabase(dbname) I;7nb4]AmF
4、转移数据库给新用户以已存在用户权限
1tB[_ $s
exec sp_change_users_login 'update_one','newname','oldname' >xu[q\:"
go a{SBCy
5、检查备份集 A5fwAB
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Ue*C>F
6、修复数据库 #eK=
ALTER DATABASE [dvbbs] SET SINGLE_USER fQ 7vL~E
GO Q6
?z_0
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ar.AL'
GO FB:<zmwR
ALTER DATABASE [dvbbs] SET MULTI_USER #z!^<,
GO aRJcSV
7、日志清除 5\Fz!
SET NOCOUNT ON {_#y z\j
DECLARE @LogicalFileName sysname, &<5+!cV=
@MaxMinutes INT, :jEPu3E:
@NewSize INT @]HXP_lyD/
USE tablename -- 要操作的数据库名 w!SkWS b,~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 TZRcd~ 5$
@MaxMinutes = 10, -- Limit on time allowed to wrap log. @
O>&5gB1u
@NewSize = 1 -- 你想设定的日志文件的大小(M) 8' K0L(3[
-- Setup / initialize \}_Yd8
DECLARE @OriginalSize int 93O;+Z5J
SELECT @OriginalSize = size zf [`~g
FROM sysfiles 8FkFM^\1L
WHERE name = @LogicalFileName a%BeqSZh
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -n5
B)uw=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + }-@4vl
x$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' '
GG=Ebt
FROM sysfiles G{9X)|d
WHERE name = @LogicalFileName l4y{m#/
CREATE TABLE DummyTrans pS[KBQ"F
(DummyColumn char (8000) not null) {/<6v. v
DECLARE @Counter INT, 7=XL!:P
@StartTime DATETIME, %7hB&[ 5
@TruncLog VARCHAR(255) J*fBZ.NO
SELECT @StartTime = GETDATE(), ILwn&[A0
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' otJ!UfpR8
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ($nrqAv4
EXEC (@TruncLog) ~8T(>!hE1h
-- Wrap the log if necessary. ,8MLoZ_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired BZv+H=b
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) v"^~&q0x
AND (@OriginalSize * 8 /1024) > @NewSize oU6y4yO
BEGIN -- Outer loop. gEQNs\Jn
L
SELECT @Counter = 0 ]bi)$j.9s
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) F^k.is
BEGIN -- update SP]IUdE\
INSERT DummyTrans VALUES ('Fill Log') p4K.NdUH
DELETE DummyTrans o4b~4h{%
SELECT @Counter = @Counter + 1 ]aryV?!6
END JUAS$Y
EXEC (@TruncLog) ~z5R{;Nbz|
END 8>WVodv
SELECT 'Final Size of ' + db_name() + ' LOG is ' + V DS23Bo
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )yK[ Zb[
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' VOTv?Vf
FROM sysfiles 'b*%ixa
WHERE name = @LogicalFileName U-kVNBs
DROP TABLE DummyTrans `qVjwJ!+
SET NOCOUNT OFF L I >(RMv
8、说明:更改某个表 )~6zYJ2
exec sp_changeobjectowner 'tablename','dbo' {nT^tAha
9、存储更改全部表 _ee
dBpV
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 7Q w|!
@OldOwner as NVARCHAR(128), 6x)$Dl
@NewOwner as NVARCHAR(128) CSPKP#,B0[
AS F}GPZ=T;
DECLARE @Name as NVARCHAR(128) YC_5YY(k
DECLARE @Owner as NVARCHAR(128) !QI\Fz?
DECLARE @OwnerName as NVARCHAR(128) bI.t<;
DECLARE curObject CURSOR FOR '})0!g<Y
select 'Name' = name, P|tNL}2`;
'Owner' = user_name(uid) `+:.L>5([
from sysobjects !HeSOzN
where user_name(uid)=@OldOwner ^u}L;`L
order by name /walu+]h
OPEN curObject *+'2?*
FETCH NEXT FROM curObject INTO @Name, @Owner (+<1*5BEkT
WHILE(@@FETCH_STATUS=0) u]+~VT1C,3
BEGIN .\0isO
if @Owner=@OldOwner W|:lVAP.|}
begin hI?sOR!
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~ 9)"!
exec sp_changeobjectowner @OwnerName, @NewOwner A\_ |un%
end +
b$=[nfG
-- select @name,@NewOwner,@OldOwner -x8nQ%X
FETCH NEXT FROM curObject INTO @Name, @Owner &!aAO(g
END }]n$ %g(
close curObject +Q=1AXe
deallocate curObject zk*c)s
GO ##Q/I|
10、SQL SERVER中直接循环写入数据 [.hyZ}B
declare @i int B+C);WQ,
set @i=1 8}X5o]Mv
while @i<30 uXDq~`S
begin Ghl'nqPlm
insert into test (userid) values(@i) g.c8FP+
set @i=@i+1 KDl_?9E5
end \)K^=jM
小记存储过程中经常用到的本周,本月,本年函数 I1oje0$
Dateadd(wk,datediff(wk,0,getdate()),-1) #_Z$2L"U
Dateadd(wk,datediff(wk,0,getdate()),6) ?m$a6'2-,J
Dateadd(mm,datediff(mm,0,getdate()),0) Uj+j}C
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) @' ;B_iQ
Dateadd(yy,datediff(yy,0,getdate()),0) 1&;QyTN
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) -[U1]R
上面的SQL代码只是一个时间段 wn_b[tdxq
Dateadd(wk,datediff(wk,0,getdate()),-1) x8\A<(G_M=
Dateadd(wk,datediff(wk,0,getdate()),6) 8:BIbmtt5
就是表示本周时间段. ?pgG,=?
下面的SQL的条件部分,就是查询时间段在本周范围内的: Yt|6
X:l
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) YEkh3FrbwH
而在存储过程中 6 3`{.yZ*z
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) V-n&oCS+f
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) SS`qJZ|w