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。 C;:L~)C@t
rnv7L^9^A
b\j&!_
一、基础 L(2P|{C
1、说明:创建数据库 VN-#R=D
CREATE DATABASE database-name aevG<|qP
2、说明:删除数据库 05VOUa*pb
drop database dbname BI.k On=
3、说明:备份sql server D6)Cjc>a
--- 创建 备份数据的 device V0
+k3H
USE master + >gbZ-S
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' nf.:5I.
--- 开始 备份 3_*Xk.
.d
BACKUP DATABASE pubs TO testBack Etc?; Z[F#
4、说明:创建新表 %i
-X@.P
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) .>64h H
根据已有的表创建新表: &}6ES{Nr8
A:create table tab_new like tab_old (使用旧表创建新表) M:UB>-`bW
B:create table tab_new as select col1,col2... from tab_old definition only m|2]lb
5、说明:删除新表 $<
K)fbG
drop table tabname hN:F8r+DG
6、说明:增加一个列 G1;'nwf}
Alter table tabname add column col type ) UDJ[pL@
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 2]aZe4H.
7、说明:添加主键: Alter table tabname add primary key(col) x+y!P
说明:删除主键: Alter table tabname drop primary key(col) j YIV^o 0
8、说明:创建索引:create [unique] index idxname on tabname(col....) }8F$&
AFt
删除索引:drop index idxname "i{_<;p O
注:索引是不可更改的,想更改必须删除重新建。 x1V2|~;p|
9、说明:创建视图:create view viewname as select statement ^8oc^LOa~2
删除视图:drop view viewname KWhM
10、说明:几个简单的基本的sql语句 -wRyMY_D
选择:select * from table1 where 范围 Jt>[]g$
插入:insert into table1(field1,field2) values(value1,value2) P`3s\8[Q
删除:delete from table1 where 范围 <r +!hJ[s'
更新:update table1 set field1=value1 where 范围 ,*nZf|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! g
y e(/N+I
排序:select * from table1 order by field1,field2 [desc] <.=#EV^i
总数:select count as totalcount from table1 [bi3%yWh
求和:select sum(field1) as sumvalue from table1 vMZ7uO
平均:select avg(field1) as avgvalue from table1 L_lDFF
最大:select max(field1) as maxvalue from table1 NBqV0>vR
最小:select min(field1) as minvalue from table1 gAr`hXO
_{c|o{2sj
/#qs(!
d
<f.>jjwFE
11、说明:几个高级查询运算词 NB
W%.z
[cQ<dVaTX
B=gsd0^]
A: UNION 运算符 ,v}?{pc
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。 XHZ:
mLf
B: EXCEPT 运算符 Q%n{*py
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。 +r-dr>&H@
C: INTERSECT 运算符 Rg?{?qK\K
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。 MB8SB
注:使用运算词的几个查询结果行必须是一致的。 #NN"(I
12、说明:使用外连接 G V:$;
A、left outer join: ~C"k$;(n
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。 N$,/Q9h^
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;N$ 0)2w
B:right outer join: u
JQaHL!
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。 dm,}Nbc91(
C:full outer join: (,Ja
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。 q
M_/
ne"?90~
x!C8?K=|
二、提升 T}t E/
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) o4/I1Mq
法一:select * into b from a where 1<>1 z
_O,Y
法二:select top 0 * into b from a 2 ]V>J
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ."IJmv
insert into b(a, b, c) select d,e,f from b; aVQSN
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) z#{0;t
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Gin_E&%g
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. rQcRjh+E
H
4、说明:子查询(表名1:a 表名2:b) mWli}j#
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) S$jV|xKB
5、说明:显示文章、提交人和最后回复时间 XVrm3aj(m
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b so!w !O@@
6、说明:外连接查询(表名1:a 表名2:b) 1tc]rC4h
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c h6\3vfj^f
7、说明:在线视图查询(表名1:a ) <'}b*wUB
select * from (SELECT a,b,c FROM a) T where t.a > 1; p<=(GY-
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 v@fe-T&0
select * from table1 where time between time1 and time2 O}K_l1
select a,b,c, from table1 where a not between 数值1 and 数值2 -t@y\vZF,
9、说明:in 的使用方法 b W=.K>|
select * from table1 where a [not] in ('值1','值2','值4','值6') 3!.H^v?
10、说明:两张关联表,删除主表中已经在副表中没有的信息
':4}O#
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) .~. ``a
11、说明:四表联查问题: @K$VV^wp
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 ..... [lNqT1%]
12、说明:日程安排提前五分钟提醒 Lj&1K~U
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 n5Nan
13、说明:一条sql 语句搞定数据库分页 :!JpP
R5
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 ]6t]m2~\
14、说明:前10条记录 k_D4'(V:b
select top 10 * form table1 where 范围 ~K~b`|1
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.) qIbg
4uE
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) rU=b?D)n!w
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
<+AI t
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?Oy'awf_
17、说明:随机取出10条数据 E0"10Qbi
select top 10 * from tablename order by newid() I 1 b
18、说明:随机选择记录 $J QWfGwR
select newid() ,4^9cFVo
19、说明:删除重复记录 Iv$:`7|crX
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) YgE]d?_h
20、说明:列出数据库里所有的表名 4M @oj
select name from sysobjects where type='U' ]d@^i)2LF
21、说明:列出表里的所有的 Zm%VG(l
select name from syscolumns where id=object_id('TableName') Gb(C#,xbK
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。 nG"tO'J6
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]A"Og_U
显示结果: }P<Qz^sr_
type vender pcs 1~}m.ER
电脑 A 1 )uQ-YC('0
电脑 A 1 (^sh
光盘 B 2 =?/N5O(
光盘 A 2 lGdM80f
手机 B 3 #TMm#?lC
手机 C 3 9=t#5J#O
23、说明:初始化表table1 N\9}\Rk@
TRUNCATE TABLE table1 J\het2?\
24、说明:选择从10到15的记录 L([E98fo
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 9z5\*b s
v5(q)h
tHrK~|
}.0Bl&\UK
三、技巧 }JRP,YNh
1、1=1,1=2的使用,在SQL语句组合时用的较多 eeuZUf+~]
"where 1=1" 是表示选择全部 "where 1=2"全部不选, :GU,EDps
如: Q)09]hP[Xj
if @strWhere !='' j*uXB^4
begin $/u1chf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere -O'{:s~
end SArfczoB
else G1]"s@8(
begin lj.nCV_
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' kTnOmAw
end H@V 7!d
我们可以直接写成 s K+
(v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere r& vFikIz
2、收缩数据库 IQ ){(Y
--重建索引 gRBSt
M&hU
DBCC REINDEX gks ==|s.
DBCC INDEXDEFRAG Lj}>Xy(7<
--收缩数据和日志 ;W]D ~X&
DBCC SHRINKDB 9|'
|BC
DBCC SHRINKFILE >;
aCf#q
3、压缩数据库 i.3cj1
dbcc shrinkdatabase(dbname) #@ 9)h
4、转移数据库给新用户以已存在用户权限 !X^Hi=aV
exec sp_change_users_login 'update_one','newname','oldname' :6XguU
go KX!i\NHz
5、检查备份集 6gXIt9B.h$
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' w{pUUo:<
6、修复数据库 <lUOJV{&\
ALTER DATABASE [dvbbs] SET SINGLE_USER j5PL{6
GO >D 97c|?c
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK >DHp*$y
GO dXmV@ Noo
ALTER DATABASE [dvbbs] SET MULTI_USER ]1m"V;vZ
GO ).LTts7c
7、日志清除 Ab/j(xr=
SET NOCOUNT ON W+_ R hJ
DECLARE @LogicalFileName sysname, p8Iw!HE
@MaxMinutes INT, 7_-w_"X
@NewSize INT
3P1&;
USE tablename -- 要操作的数据库名 ~
|6dH
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 :M06 ;:e
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [r(Qs|
@NewSize = 1 -- 你想设定的日志文件的大小(M) r#A_RZ2~@
-- Setup / initialize 7KU~(?|:h
DECLARE @OriginalSize int z"lqrSJ:
SELECT @OriginalSize = size /RGNAHtIi
FROM sysfiles @5WgqB
WHERE name = @LogicalFileName r!7 Y'|
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "< v\M85&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ['z!{Ez
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' n|Pr/ddL
FROM sysfiles -T7%dLHY
WHERE name = @LogicalFileName b/t
CREATE TABLE DummyTrans } ^i b
(DummyColumn char (8000) not null) -_NC%iN#C
DECLARE @Counter INT, =VNSiK>F
@StartTime DATETIME, l[ne/O
JJ
@TruncLog VARCHAR(255) Ir5WN_EaS
SELECT @StartTime = GETDATE(), %JtbRs(~q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1"}cdq.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Z?oG*G:
EXEC (@TruncLog) 9}5K6aQ
-- Wrap the log if necessary. CswE
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired in<}fAro6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) R[LsE^
AND (@OriginalSize * 8 /1024) > @NewSize )t:7_M3
BEGIN -- Outer loop. *5e+@rD`
SELECT @Counter = 0 Bd@'e7{
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Zk&h:c
BEGIN -- update w5*Z!
INSERT DummyTrans VALUES ('Fill Log') Jic}+X*0
DELETE DummyTrans X eoJ$PfT
SELECT @Counter = @Counter + 1 9XX>A*
END K^zDNIQU
EXEC (@TruncLog) !Vheq3"q/
END RW_q~bA9
SELECT 'Final Size of ' + db_name() + ' LOG is ' + (DDyK[t+VX
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + *XbI#L%>
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ME^,'&
FROM sysfiles ,`32!i
WHERE name = @LogicalFileName GMW,*if8p
DROP TABLE DummyTrans 3LDsxE=N:q
SET NOCOUNT OFF Gs
dnf 7
8、说明:更改某个表 ;Wc4qJ.@
exec sp_changeobjectowner 'tablename','dbo' (vc|7DX M
9、存储更改全部表 HSN8O@dy
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8!mc@$Z
@OldOwner as NVARCHAR(128), >`'O7.R
@NewOwner as NVARCHAR(128) e}0:"R%E
AS p_{("zQ
DECLARE @Name as NVARCHAR(128) O oSb>Y/4
DECLARE @Owner as NVARCHAR(128) A5fwAB
DECLARE @OwnerName as NVARCHAR(128) /qU>5;
DECLARE curObject CURSOR FOR k%P;w1
select 'Name' = name, ~9=aT1S|
'Owner' = user_name(uid) w8iR|TV
from sysobjects ]XeO0Y
where user_name(uid)=@OldOwner C5W>W4EM
order by name b.F^vv"]]
OPEN curObject Vw#{C>
FETCH NEXT FROM curObject INTO @Name, @Owner :!fG; )=
WHILE(@@FETCH_STATUS=0) WKmbNvN^
BEGIN K>2 #UzW
if @Owner=@OldOwner Xf
d*D
begin ,e`'4H
set @OwnerName = @OldOwner + '.' + rtrim(@Name) -?6MU~"GK
exec sp_changeobjectowner @OwnerName, @NewOwner PXzT6)
end U47}QDh
-- select @name,@NewOwner,@OldOwner vyI%3+N@
FETCH NEXT FROM curObject INTO @Name, @Owner ,RxYd6
END 0)!Ll*L!p
close curObject &\C [@_
deallocate curObject VR5fqf|*
GO (*\jbK
10、SQL SERVER中直接循环写入数据 X"q!Y#)
declare @i int k~3.MU
set @i=1 in-C/m#
while @i<30 hWo=;#B*
begin ]3Dl)[R
insert into test (userid) values(@i) LfLFu9#:w
set @i=@i+1 ;heHefbvvd
end x;\wY'
小记存储过程中经常用到的本周,本月,本年函数 xJZ@DR,#
Dateadd(wk,datediff(wk,0,getdate()),-1) X|DO~{-au
Dateadd(wk,datediff(wk,0,getdate()),6) x9W(cKB'S
Dateadd(mm,datediff(mm,0,getdate()),0) /mM2M-
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) O
5Nb
Dateadd(yy,datediff(yy,0,getdate()),0) <3okiV=ox
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) !yOeW0/2[
上面的SQL代码只是一个时间段 SC &~s$P;
Dateadd(wk,datediff(wk,0,getdate()),-1) <spZ! #o
Dateadd(wk,datediff(wk,0,getdate()),6) ]i*](UQ
就是表示本周时间段. $gpG%Qj
下面的SQL的条件部分,就是查询时间段在本周范围内的: fyWO
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) *&Lq!rFS
而在存储过程中 SP]IUdE\
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) p4K.NdUH
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) L,,*gK