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^O{"au^
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一、基础 wxH(&CB-{
1、说明:创建数据库 -B<O_*wOj
CREATE DATABASE database-name DN4fP-m-
2、说明:删除数据库 E~rs11
drop database dbname :5$xh
3、说明:备份sql server )[e%wPu4e
--- 创建 备份数据的 device Z TN:|IKT
USE master y21)~
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' L7i}Ga!8
--- 开始 备份 16a_GwfM
BACKUP DATABASE pubs TO testBack E\
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4、说明:创建新表 E`A<]dAoK
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) L"Qh_+
根据已有的表创建新表: i5ajM,i/K
A:create table tab_new like tab_old (使用旧表创建新表) R>/QARX
B:create table tab_new as select col1,col2... from tab_old definition only
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5、说明:删除新表 D2>hMc
drop table tabname ^#<:<X6
6、说明:增加一个列 g,A.Y,})
Alter table tabname add column col type [K"U_b}w
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 e6tH/`Uln
7、说明:添加主键: Alter table tabname add primary key(col) N*_/@qM> a
说明:删除主键: Alter table tabname drop primary key(col) z Y$X|=f
8、说明:创建索引:create [unique] index idxname on tabname(col....) "3U{h]
删除索引:drop index idxname j;ff } b
注:索引是不可更改的,想更改必须删除重新建。 ,\\%EZ%a
9、说明:创建视图:create view viewname as select statement %RCl+hOP.h
删除视图:drop view viewname ]+^;vc 1r
10、说明:几个简单的基本的sql语句 s_S<gR
选择:select * from table1 where 范围 NqQM!B]
插入:insert into table1(field1,field2) values(value1,value2) ^8o_Iz)r,
删除:delete from table1 where 范围 2N8rM}?90
更新:update table1 set field1=value1 where 范围 g:G%Ei~sF
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! "N?%mCPI
排序:select * from table1 order by field1,field2 [desc] # i`A4D
总数:select count as totalcount from table1 d,GtH)( s
求和:select sum(field1) as sumvalue from table1 [ u`17hyX
平均:select avg(field1) as avgvalue from table1 o2[vM$]
最大:select max(field1) as maxvalue from table1 z5|e\Z
最小:select min(field1) as minvalue from table1 hLDch5J5~
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11、说明:几个高级查询运算词 &cv@Kihq(
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A: UNION 运算符 C8bGae(
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 0%GqCg
B: EXCEPT 运算符 CjC'"+[w
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 p=mCK@
C: INTERSECT 运算符 v!pj v%
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 l|R<F;|
注:使用运算词的几个查询结果行必须是一致的。 N$=(1`zM=
12、说明:使用外连接 ;~'cITL
A、left outer join: dy2_@/T7
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。 cJ7{4YK_#/
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 4~MJ4:
B:right outer join: Zq\RNZ}
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。 2$j
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C:full outer join: AHp830\
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 :{TmR3.
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二、提升 .BYKdxa
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 Xh7~MU~X
法二:select top 0 * into b from a YJ$Vn>6Z
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) + WU|sAK"
insert into b(a, b, c) select d,e,f from b; IF36K^K
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) gW6G+
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6oTbn{=UUq
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. %h/#^esi
4、说明:子查询(表名1:a 表名2:b) ^\7 x5gO
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) 2$SofG6D}
5、说明:显示文章、提交人和最后回复时间 20Cie
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (T%F!2i([U
6、说明:外连接查询(表名1:a 表名2:b) !TV_dKa
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^.Ih,@N6
7、说明:在线视图查询(表名1:a ) niBjq#bJi
select * from (SELECT a,b,c FROM a) T where t.a > 1; |%2/I>o
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 =,>TpE
select * from table1 where time between time1 and time2 y'0dl "Dy\
select a,b,c, from table1 where a not between 数值1 and 数值2 HX /GLnY/X
9、说明:in 的使用方法 |&0"N[t
select * from table1 where a [not] in ('值1','值2','值4','值6') .%J?T5D
10、说明:两张关联表,删除主表中已经在副表中没有的信息 xnRp/I
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) T~wZ
11、说明:四表联查问题: Dh!iY0Lz
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... k+7M|t.?4
12、说明:日程安排提前五分钟提醒 R$T[%AGZ.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 &k_wqV
13、说明:一条sql 语句搞定数据库分页 Bah.\ZsYQP
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 [d^:
14、说明:前10条记录 [U3D`V$xD
select top 10 * form table1 where 范围 #iRyjD
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) @o3R`ZgC]\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) c:@OX[##
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 5E\<r/FeJ
(select a from tableA ) except (select a from tableB) except (select a from tableC) Jm);|#y
17、说明:随机取出10条数据 9znx1AsN
select top 10 * from tablename order by newid() |=^#d\?]j
18、说明:随机选择记录 *Sz{DE1U
select newid() C<wj?!v,F[
19、说明:删除重复记录 \:q e3Q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ~J. Fl[
20、说明:列出数据库里所有的表名 VkN[=0a,
select name from sysobjects where type='U' Tk v
21、说明:列出表里的所有的 }n2-*{)x
select name from syscolumns where id=object_id('TableName') aaqd:N)
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 O{i_?V_
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type QGbD=c7
显示结果: {xBjEhQm
type vender pcs Z$#ZYD
电脑 A 1 eMm~7\
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电脑 A 1 U$/Hp#~X
光盘 B 2 +2au
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光盘 A 2 z:i X]df
手机 B 3 AHMV@o`V
手机 C 3 fN"oa>X
23、说明:初始化表table1 -'H+lrmv
TRUNCATE TABLE table1 Br ^rK}|l
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc *a4b`HRT
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三、技巧 Hdq/E>u
1、1=1,1=2的使用,在SQL语句组合时用的较多 U@v8H!p^i
"where 1=1" 是表示选择全部 "where 1=2"全部不选, yd2qf
如: |`(?<m
if @strWhere !=''
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begin <v7KE*#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere -o!,,XYj .
end ]}l+ !NV<
else B[0,\>
begin Am0.c0h
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' "!6 B5Oz
end @Z=|$*9
我们可以直接写成 i!d7,>l+Q~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7 NB"oU^h%
2、收缩数据库 1=q?#PQ
--重建索引 aWsKJo>j[#
DBCC REINDEX X+gz+V/
DBCC INDEXDEFRAG oCdOC5
--收缩数据和日志 M(h H#_$
DBCC SHRINKDB ;\*Od?1
DBCC SHRINKFILE ,@>rubUz
3、压缩数据库 f`9rTc
dbcc shrinkdatabase(dbname) -SY:qG3?
4、转移数据库给新用户以已存在用户权限 |nH0~P#!
exec sp_change_users_login 'update_one','newname','oldname' rIFC#Jd/
go }AsF\W+5
5、检查备份集 :D+SY
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' iUG/
6、修复数据库 <]e;tF)+
ALTER DATABASE [dvbbs] SET SINGLE_USER 'Rh>w=wB'
GO 9hs{uxwuEE
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK zs&`:
GO hv:Z%D |S
ALTER DATABASE [dvbbs] SET MULTI_USER ep}/dBg
GO bq6{ty"
7、日志清除 e>zk3\D!
SET NOCOUNT ON 4tTZkJc
DECLARE @LogicalFileName sysname, q' V{vFfY%
@MaxMinutes INT, ot+~|Dl
@NewSize INT *1)NABp6D
USE tablename -- 要操作的数据库名 qQ
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2#:]%y;\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. uF3p1by
@NewSize = 1 -- 你想设定的日志文件的大小(M) K<L%@[gi
-- Setup / initialize <K[Zl/7I
DECLARE @OriginalSize int 9MzkG87J
SELECT @OriginalSize = size POg0=32
FROM sysfiles 5 EuJ
WHERE name = @LogicalFileName 8Y0<lfG
SELECT 'Original Size of ' + db_name() + ' LOG is ' + IV)W|/.
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 5Kw?SRFH/
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' --%2=.X=
FROM sysfiles S5
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WHERE name = @LogicalFileName A-wxf91+:
CREATE TABLE DummyTrans a=B0ytNm
(DummyColumn char (8000) not null) 5NF&LM;i(
DECLARE @Counter INT, qCkg\)Ks5I
@StartTime DATETIME, DF[b?
@TruncLog VARCHAR(255) u4+uGYr*@
SELECT @StartTime = GETDATE(), KW6" +,Th
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' vzm4
DBCC SHRINKFILE (@LogicalFileName, @NewSize) E|4XQ|B@
EXEC (@TruncLog) 2V"gqJHv
-- Wrap the log if necessary. 5GFnfc}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired XK/@!ud"`
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (l P4D:X
AND (@OriginalSize * 8 /1024) > @NewSize YxkEAb!+
BEGIN -- Outer loop. KP7RrgOan&
SELECT @Counter = 0 ?ZV0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ^oB1 &G
BEGIN -- update 1&pP}v ?
INSERT DummyTrans VALUES ('Fill Log') |M/
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DELETE DummyTrans PZhZK
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SELECT @Counter = @Counter + 1 OK J%M]<
END JHZo:Ad -&
EXEC (@TruncLog) :=7 '1H
END x71!r
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 5)v^
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + gwz _b
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' udy;Odt
FROM sysfiles q4ko}jn
WHERE name = @LogicalFileName 6:z&ukqE
DROP TABLE DummyTrans 3L]^x9Cu)
SET NOCOUNT OFF RH4n0=2
8、说明:更改某个表 "l,EcZRjTz
exec sp_changeobjectowner 'tablename','dbo' Lm{ o=v
9、存储更改全部表 (dipKs?K
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ,h`D(,?X
@OldOwner as NVARCHAR(128), t RyGxqiG
@NewOwner as NVARCHAR(128) 6Vzc:8o>
AS 2,Dc]oj
DECLARE @Name as NVARCHAR(128) /"{ ,m!
DECLARE @Owner as NVARCHAR(128) +sl uu!~
DECLARE @OwnerName as NVARCHAR(128) RR[TW;
DECLARE curObject CURSOR FOR bNU^tL3QZ
select 'Name' = name, ,UZE;lXJ'Q
'Owner' = user_name(uid) KJC9^BAr
from sysobjects _po 4(U&
where user_name(uid)=@OldOwner L"IHyUW
order by name a4.:
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OPEN curObject KdpJ[[Ug/
FETCH NEXT FROM curObject INTO @Name, @Owner ZL@DD(S-/
WHILE(@@FETCH_STATUS=0) \ g(#)f
BEGIN (*Q|;
if @Owner=@OldOwner YY<?w
begin <_q/ +x]8
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ;f^jB;\<
exec sp_changeobjectowner @OwnerName, @NewOwner vm^# aoDB
end D"f(nVEr
-- select @name,@NewOwner,@OldOwner }UdqX1jz
FETCH NEXT FROM curObject INTO @Name, @Owner E
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END )-"L4TC)
close curObject *dTf(J
deallocate curObject J+gsmP-_
GO :{uUc
10、SQL SERVER中直接循环写入数据 s(.-bjR
declare @i int @N{Ht)1r
set @i=1 |+~2sbM
while @i<30 3i}B\
{
begin |3@Pt>Ikl
insert into test (userid) values(@i) _-\{kJ
set @i=@i+1 &LQab>{*K
end TC#B^m`'p
小记存储过程中经常用到的本周,本月,本年函数 q.F1Jj
Dateadd(wk,datediff(wk,0,getdate()),-1) B"zg85
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Dateadd(wk,datediff(wk,0,getdate()),6) [eP]8G\
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Dateadd(mm,datediff(mm,0,getdate()),0) #7T ={mh
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) J5IJy3d
Dateadd(yy,datediff(yy,0,getdate()),0) -XG$ 0
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) h5keYBA
上面的SQL代码只是一个时间段 7uNI
Dateadd(wk,datediff(wk,0,getdate()),-1) be#"517
Dateadd(wk,datediff(wk,0,getdate()),6) -y*+G&
就是表示本周时间段. (UT*T
下面的SQL的条件部分,就是查询时间段在本周范围内的: .T-p]9*p
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) (
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而在存储过程中 8N_rJ)f
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) cGp 6yf
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6e|5qKr