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。 hPkp;a #
G[ PtkPSJ
#\{l"-
一、基础 E_rI?t^
1、说明:创建数据库 =jN.1}
CREATE DATABASE database-name b=C*W,Q_#
2、说明:删除数据库 As&Sq-NWf
drop database dbname ZvM(Q=^
3、说明:备份sql server yZY \MB/
--- 创建 备份数据的 device qz_7%c]K[
USE master LBeF&sb6
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' )MVz$h{c.]
--- 开始 备份 Pm6pv;WK
BACKUP DATABASE pubs TO testBack K-)]
1BG
4、说明:创建新表 M)Z7k/=<P
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ;fTKfa
根据已有的表创建新表: HQdxL*N%^
A:create table tab_new like tab_old (使用旧表创建新表) ,Zx0%#6
B:create table tab_new as select col1,col2... from tab_old definition only
z_$% -6
5、说明:删除新表 Y(ykng
drop table tabname 6GlJ>r+n
6、说明:增加一个列 RMV/&85?y
Alter table tabname add column col type 6yG^p]zZ
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。 g{)dP!}
7、说明:添加主键: Alter table tabname add primary key(col) ^LnTOdAE
说明:删除主键: Alter table tabname drop primary key(col) N{!i=A
8、说明:创建索引:create [unique] index idxname on tabname(col....) KfEx"94
删除索引:drop index idxname ,<_A2t 2
注:索引是不可更改的,想更改必须删除重新建。 B:Oa}/H
9、说明:创建视图:create view viewname as select statement #P9~}JB3,
删除视图:drop view viewname )u&|_&g{}J
10、说明:几个简单的基本的sql语句 d'gfQlDny
选择:select * from table1 where 范围 F~vuM$+d
插入:insert into table1(field1,field2) values(value1,value2) ,2oWWsC7
删除:delete from table1 where 范围 C3f' {}
更新:update table1 set field1=value1 where 范围 ! I:%0D
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! df +l%9@
排序:select * from table1 order by field1,field2 [desc] )r?}P1J7
总数:select count as totalcount from table1 KZY}%il!`
求和:select sum(field1) as sumvalue from table1 _yx>TE2e
平均:select avg(field1) as avgvalue from table1 VT)oLj/A
最大:select max(field1) as maxvalue from table1 3*XNV
最小:select min(field1) as minvalue from table1 }"H,h)T
R%WCH?B<}
yxQ1`'[CR
net@j#}j-
11、说明:几个高级查询运算词 &m7]v,&
Xu'&ynID
8FK/~,I
A: UNION 运算符 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。 H2 {+)
B: EXCEPT 运算符 u~:y\/Y6
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。 x_}:D *aI
C: INTERSECT 运算符 Lg+Ac5y}`
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。 +) om^e@.
注:使用运算词的几个查询结果行必须是一致的。 qA7>vi%
12、说明:使用外连接 k"%~"9
A、left outer join: NiEUW.0
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。 RLXL&
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 ,-LwtePJ0
B:right outer join: NA`SyKtg_
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。 Rok7n1gW
C:full outer join: UgSB>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。 O63<AY@
2wg5#i
558V_y:
二、提升 8'[7
)I=
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~W'{p
法一:select * into b from a where 1<>1 9L?.m&
法二:select top 0 * into b from a 8 >EWKI9
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) <al(7
insert into b(a, b, c) select d,e,f from b; =o(5_S.u;
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) 9&2O9Nz6
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 8^2oWC#U(
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. t|\%VC
4、说明:子查询(表名1:a 表名2:b) I*{nP)^9
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) T*Exs|N2P-
5、说明:显示文章、提交人和最后回复时间 LmrfN?5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b myQagqRx
6、说明:外连接查询(表名1:a 表名2:b) ~H_/zK6e
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c nNV'O(x}
7、说明:在线视图查询(表名1:a ) =:Fc;n>c<K
select * from (SELECT a,b,c FROM a) T where t.a > 1; Fnv;^}\z
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 %N6A+5H
select * from table1 where time between time1 and time2 ~
'cmSiz-
select a,b,c, from table1 where a not between 数值1 and 数值2 xh,qNnGGi
9、说明:in 的使用方法 Lx1FpHo
select * from table1 where a [not] in ('值1','值2','值4','值6') ,kGc]{'W
10、说明:两张关联表,删除主表中已经在副表中没有的信息 `2WFk8) F
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )[6U^j4
11、说明:四表联查问题: xC:L)7#aw
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 ..... qJs<#MQ2
12、说明:日程安排提前五分钟提醒 #U4F0BdA
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Gr'
CtO
13、说明:一条sql 语句搞定数据库分页 L#?Ek-
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 h 8S. x)
14、说明:前10条记录 4r#= *
select top 10 * form table1 where 范围 iL&fgF"'
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.) 6r0krbN
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) %D34/=(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 {SPq$B_VR
(select a from tableA ) except (select a from tableB) except (select a from tableC) Oc#syfO
17、说明:随机取出10条数据 HYZ5EV
select top 10 * from tablename order by newid() ItVWO:x&v
18、说明:随机选择记录 %6,SKg p
select newid() &X ):4
19、说明:删除重复记录 -H@:*
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) d#Y^>"|$.
20、说明:列出数据库里所有的表名 P>C~
i:4n
select name from sysobjects where type='U' z"L/G
21、说明:列出表里的所有的 W~;`WR;.
select name from syscolumns where id=object_id('TableName') Lc,Pom
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ~9]hV7y5C
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Qh3YJ=X&
显示结果: ||= )d&
type vender pcs RDi]2
电脑 A 1 o Q2Fjj
电脑 A 1 ?0?#U0(;u
光盘 B 2 :yr+vcD?
光盘 A 2 Ad8n<zt|
手机 B 3 wLH>:yKUU
手机 C 3 bKY7/w<dP
23、说明:初始化表table1 gIa+5\qYY
TRUNCATE TABLE table1 )3}9K
^jS
24、说明:选择从10到15的记录 )JLdO*H
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc nI-w}NQ
g"DG]/ev
~{g [<Qi
mt{nm[D!Xp
三、技巧 KIf dafRL
1、1=1,1=2的使用,在SQL语句组合时用的较多 pfD c9PMj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, -t'jNR'
如: Y'S%O/$
if @strWhere !='' -q1??u
begin @Z
%ivR:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,X-bJA@(
end F=e8 IUr
else \BTODZ:h
begin IGQaDFr
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 4#xDgxg\f
end jyUjlYAAv`
我们可以直接写成 9igiZmM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Q800y??&J
2、收缩数据库 dI(@ZV{
--重建索引 :Zbg9`d*
DBCC REINDEX jh%Eq+#S
DBCC INDEXDEFRAG x(6SG+Kr
--收缩数据和日志 KNvZm;Q6
DBCC SHRINKDB gnOt+W8
DBCC SHRINKFILE @ $ ;q;
3、压缩数据库 5|j<`()H
:
dbcc shrinkdatabase(dbname) >}8j+t&T
4、转移数据库给新用户以已存在用户权限 Lv;^My
exec sp_change_users_login 'update_one','newname','oldname' %KhI>O<
go 36Zf^cFJ
5、检查备份集 9@(PWz=`?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' D9=KXo^
6、修复数据库 JN-y)L/>
ALTER DATABASE [dvbbs] SET SINGLE_USER (AaoCa[
GO %KlrSo
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK x.!V^HQSN
GO ZF9z~9
ALTER DATABASE [dvbbs] SET MULTI_USER ]?kZni8j_
GO ghG**3xr
7、日志清除 {j?FNOJn
SET NOCOUNT ON xQ-<WF1i
DECLARE @LogicalFileName sysname, N1}sHyVq7
@MaxMinutes INT, u<tbbKM
@NewSize INT yy^q2P
USE tablename -- 要操作的数据库名 '4+
ur`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 -hGk?_Nqa/
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 6 l|DU7i
@NewSize = 1 -- 你想设定的日志文件的大小(M) 9k'7832u
-- Setup / initialize 30#s aGV
DECLARE @OriginalSize int /tx]5`#@7]
SELECT @OriginalSize = size ;~)5s'
FROM sysfiles XH 4
WHERE name = @LogicalFileName %+W{iu[|
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |^"1{7)
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + |P
HT694Uz
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' f;o5=)Y
FROM sysfiles eCU:Q
WHERE name = @LogicalFileName "Y
=;.:qe
CREATE TABLE DummyTrans .PIL
+x*]N
(DummyColumn char (8000) not null) BDW^7[n
DECLARE @Counter INT, o4F2%0gJ
@StartTime DATETIME, s^G.]%iU
@TruncLog VARCHAR(255) 3=P]x;[ba
SELECT @StartTime = GETDATE(), 6
6EV$*dRL
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' NqazpB*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) w7.V6S$Ga
EXEC (@TruncLog) # Yj 1w
-- Wrap the log if necessary. bQg:zww
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Ha0M)0Anv
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p J!
mw\:
AND (@OriginalSize * 8 /1024) > @NewSize /!yU!`bY
BEGIN -- Outer loop. h,u,^ r
SELECT @Counter = 0 %op**@4/t\
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) B[Ku\A6&
BEGIN -- update )1J R#
INSERT DummyTrans VALUES ('Fill Log') Xv5wJlc!d
DELETE DummyTrans Ct <udO
SELECT @Counter = @Counter + 1 _/s$ZCd
END p?%y82E
EXEC (@TruncLog) P:K5",)
END ul6]!Iy
SELECT 'Final Size of ' + db_name() + ' LOG is ' + qdJ=lhHM}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ?4#Li~q
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' F4-$~v@
FROM sysfiles In"ZIKaC
WHERE name = @LogicalFileName ok"k*?Ov
DROP TABLE DummyTrans b5dD/-Vj
SET NOCOUNT OFF 7UKh688
8、说明:更改某个表 KI iO
exec sp_changeobjectowner 'tablename','dbo' 6EoMt@7g
9、存储更改全部表 O-0x8 O^B
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ?DS@e@lx
@OldOwner as NVARCHAR(128), fM :]&
@NewOwner as NVARCHAR(128) x/I%2F
AS B?gOHG*vd>
DECLARE @Name as NVARCHAR(128) $Ps|HN
DECLARE @Owner as NVARCHAR(128) Af~$TyX
DECLARE @OwnerName as NVARCHAR(128) >^?u
.gM3
DECLARE curObject CURSOR FOR `t>l:<@%
select 'Name' = name, iJ)_RSFK
'Owner' = user_name(uid) 9IdA%RM~mH
from sysobjects >UTBO|95y
where user_name(uid)=@OldOwner #K_ii)n
order by name +6M}O[LP
OPEN curObject HTv2#
FETCH NEXT FROM curObject INTO @Name, @Owner }<0BX \@I
WHILE(@@FETCH_STATUS=0) FJGlP&v<
BEGIN `!3SF|x&
if @Owner=@OldOwner @|Cz-J;D
begin Tt`u:ZwhF
set @OwnerName = @OldOwner + '.' + rtrim(@Name) #'nr
Er <
exec sp_changeobjectowner @OwnerName, @NewOwner P+
3G~Sr
end xf\ C|@i
-- select @name,@NewOwner,@OldOwner J\}twYty
FETCH NEXT FROM curObject INTO @Name, @Owner Fo (fWvz
END hlvK5Z
close curObject &.)^
%Tp\z
deallocate curObject x$A+lj]x
GO xA2YG|RU=b
10、SQL SERVER中直接循环写入数据 n:I,PS0H<
declare @i int c)6m$5]
set @i=1 fZGX}T<)p-
while @i<30 .ljnDL/
begin kUL'1!j7
insert into test (userid) values(@i) RtkEGxw*^
set @i=@i+1 /Y:sLGQLD
end zJKv'>?
小记存储过程中经常用到的本周,本月,本年函数 /Iu1L#
Dateadd(wk,datediff(wk,0,getdate()),-1) P[G)sA_"
Dateadd(wk,datediff(wk,0,getdate()),6) kf\PioD8
Dateadd(mm,datediff(mm,0,getdate()),0) l?v86k
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) b"<liGh"n-
Dateadd(yy,datediff(yy,0,getdate()),0) TM__I\+Q
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) n$A9_cHF7
上面的SQL代码只是一个时间段 imhwY#D
Dateadd(wk,datediff(wk,0,getdate()),-1) <6%?OJhp
Dateadd(wk,datediff(wk,0,getdate()),6) 58}U^IW
就是表示本周时间段. 6IN
e@
下面的SQL的条件部分,就是查询时间段在本周范围内的: U#7#aeI
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) p}}R-D&K
而在存储过程中 x xHY+(m
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) S1T"Z{$
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) <VMGTBVQ