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。 )<{u
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一、基础 O!^ >YvOh
1、说明:创建数据库 KeRC8mYp
CREATE DATABASE database-name xm1'
2、说明:删除数据库 #"lb9._M
drop database dbname /!^,+
3、说明:备份sql server *^Ges;5$"
--- 创建 备份数据的 device ZNM9@;7
USE master |TP,
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^,mN-.W
--- 开始 备份 lM}-'8tt?
BACKUP DATABASE pubs TO testBack
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4、说明:创建新表 /H"fycZ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )Tp"l"(G
根据已有的表创建新表: 09trFj$L
A:create table tab_new like tab_old (使用旧表创建新表) 7(uz*~Z?`0
B:create table tab_new as select col1,col2... from tab_old definition only dP+wcl4
5、说明:删除新表 DB65vM
drop table tabname ,|3_@tUl
6、说明:增加一个列 ?o$t{AQ
Alter table tabname add column col type WJu(,zM?G
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 >j3':>\U
7、说明:添加主键: Alter table tabname add primary key(col) 7}y@VO6]
说明:删除主键: Alter table tabname drop primary key(col) 6wj o:I
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9(OeH7
删除索引:drop index idxname d(TN(6g@
注:索引是不可更改的,想更改必须删除重新建。 B@NBN&Fr
9、说明:创建视图:create view viewname as select statement h# KSKKNW
删除视图:drop view viewname bmK
10、说明:几个简单的基本的sql语句 4L ]4WVc
选择:select * from table1 where 范围 `GW&*[.7
插入:insert into table1(field1,field2) values(value1,value2) iw=e"6V
删除:delete from table1 where 范围 sNcU>qjj6
更新:update table1 set field1=value1 where 范围 p
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! U,Uy0s2r
排序:select * from table1 order by field1,field2 [desc] od5nRb
总数:select count as totalcount from table1 m;\nMdn
求和:select sum(field1) as sumvalue from table1 jf`w8*R
平均:select avg(field1) as avgvalue from table1 rab$[?]
最大:select max(field1) as maxvalue from table1 FU/:'/ L
最小:select min(field1) as minvalue from table1 4w=v
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11、说明:几个高级查询运算词 .r{t&HO;Y
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A: UNION 运算符 ~tyqvHC
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。 j6RV{Lkr_
B: EXCEPT 运算符 c0o Z7)*}
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。 "igA^^?X1N
C: INTERSECT 运算符 R9 Ab.t
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。 )^AZmUYZ
注:使用运算词的几个查询结果行必须是一致的。 \8!CKnfs
12、说明:使用外连接
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A、left outer join: _pZ
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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。 A[^#8evaK
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 dor1(@no|
B:right outer join: k ,ldi
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。 G+Z ,ic
C:full outer join: ,Yx<"2 W
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。 #b;k+<n[X
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二、提升 E:B"!Y6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) #::+# G
法一:select * into b from a where 1<>1 a>W++8t1 ;
法二:select top 0 * into b from a >
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 7gN;9pc$
insert into b(a, b, c) select d,e,f from b; pZopdEFDK|
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) 6E
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 5,##p"O(
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. -dO8Uis$
4、说明:子查询(表名1:a 表名2:b) q4w]9b/
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) I:/|{:5
5、说明:显示文章、提交人和最后回复时间 A+8)VlE\
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ;$zvm`|:
6、说明:外连接查询(表名1:a 表名2:b) "qF/7`e[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c \%Y`>x.
7、说明:在线视图查询(表名1:a ) NQ;X|$!zH
select * from (SELECT a,b,c FROM a) T where t.a > 1; 97\K ]Tr
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 |8~)3P k
select * from table1 where time between time1 and time2 k(^TXUK\o
select a,b,c, from table1 where a not between 数值1 and 数值2 |v8hg])I+
9、说明:in 的使用方法 &
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select * from table1 where a [not] in ('值1','值2','值4','值6') #}B1W&\sw
10、说明:两张关联表,删除主表中已经在副表中没有的信息 qpjZ-[UC
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Um\HX6
11、说明:四表联查问题: .=Oww
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 ..... _q#pEv
12、说明:日程安排提前五分钟提醒 EjFpQ|-L|
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 dWiNe!oY2
13、说明:一条sql 语句搞定数据库分页 P ?f${t+
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 hBnUpYec
14、说明:前10条记录 F"k`PF*b
select top 10 * form table1 where 范围 B>:U
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) i6k6l%
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 2^
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 lSaX!${R'T
(select a from tableA ) except (select a from tableB) except (select a from tableC) XXn3K BIf
17、说明:随机取出10条数据 #J3o~,t<
select top 10 * from tablename order by newid() \P+^BG!
18、说明:随机选择记录 ]
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select newid() $%\6"P/64
19、说明:删除重复记录 XZ]ji9'
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !;(Wm6~*ad
20、说明:列出数据库里所有的表名 ()Kaxcs?+
select name from sysobjects where type='U' kN1R8| pv
21、说明:列出表里的所有的 vJGH8$%;,
select name from syscolumns where id=object_id('TableName')
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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。 FCEmg0qdjD
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 "Y L^j~A
显示结果: BK4S$B
type vender pcs d3q.i5']G
电脑 A 1 5o 5DG
电脑 A 1
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光盘 B 2 "GZ}+K*GG
光盘 A 2 %V]v,
手机 B 3 sV2D:%\K:
手机 C 3 L5 Cfa-
23、说明:初始化表table1 5PZ7-WJ/
TRUNCATE TABLE table1 Q&{C%j~N
24、说明:选择从10到15的记录 -r<8mL:yW
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc $Ugc:L<h+
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三、技巧 X)hpbHa
1、1=1,1=2的使用,在SQL语句组合时用的较多 1ow,'FztPt
"where 1=1" 是表示选择全部 "where 1=2"全部不选, tjRwbnT"
如: 4[x`\
if @strWhere !='' \
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begin 8%u|[Si;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $`7Fk%#+e
end 6M7GPHah
else
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begin N atC}k
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' v5\ALWy+p
end [Z2[Iy
我们可以直接写成 \^9n&MonM
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere }%?or_f/
2、收缩数据库 o96c`a u
--重建索引 KJOb1MM
DBCC REINDEX #tHYCSr]
DBCC INDEXDEFRAG &x\)] i2f
--收缩数据和日志 0aY\(@
DBCC SHRINKDB cq?,v?m
DBCC SHRINKFILE IFew3!{\
3、压缩数据库 qF$y
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dbcc shrinkdatabase(dbname) U4-RI]Cpf
4、转移数据库给新用户以已存在用户权限 $$.q6
exec sp_change_users_login 'update_one','newname','oldname' ,.(:b82$
go 5lD`qY
5、检查备份集 "@^<~bw
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ~=c5q
6、修复数据库 ~ L%,9
ALTER DATABASE [dvbbs] SET SINGLE_USER /v<Gt%3X
GO +U
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;%
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GO B.od{@I(Xp
ALTER DATABASE [dvbbs] SET MULTI_USER mD% qDKI
GO C.#Ha-@uz
7、日志清除 ]?T^tJ
SET NOCOUNT ON Hpz1Iy@
DECLARE @LogicalFileName sysname, >f Hu
@MaxMinutes INT, HxW/t7Z(
@NewSize INT l
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USE tablename -- 要操作的数据库名
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 x?B`p"ifS
@MaxMinutes = 10, -- Limit on time allowed to wrap log. rp<~=X
@NewSize = 1 -- 你想设定的日志文件的大小(M) G7`mK}J7
-- Setup / initialize J5jI/P
DECLARE @OriginalSize int 6p&2A
SELECT @OriginalSize = size ( z)#}TC
FROM sysfiles V*O[8s%5v
WHERE name = @LogicalFileName H1q,w|O9j
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ;:oJFI#;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {`*Fu/Upb
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' +924_,zF
FROM sysfiles "2-D[rYZ
WHERE name = @LogicalFileName Z]{=Jy!F
CREATE TABLE DummyTrans mDp8JNJNE
(DummyColumn char (8000) not null) {g[kn^|
DECLARE @Counter INT, ndDF(qHr
@StartTime DATETIME, "AXgT[ O
@TruncLog VARCHAR(255) DAf@-~c
SELECT @StartTime = GETDATE(), Q.jThP`p
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' -wx~*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) :%AEwRZ
EXEC (@TruncLog) C:sgT6
-- Wrap the log if necessary. %wru)
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired G?LC!9MB
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 'lpCwH
AND (@OriginalSize * 8 /1024) > @NewSize WQN`y>1#@_
BEGIN -- Outer loop. ?8s$RYp14
SELECT @Counter = 0 5`e;l$
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *v(Q-FW
BEGIN -- update y"7*u
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INSERT DummyTrans VALUES ('Fill Log') p`\>GWuT!
DELETE DummyTrans _}JMBIq$
SELECT @Counter = @Counter + 1 TYR \K
END wBw(T1VN
EXEC (@TruncLog) Iy;"ht6
END PU%f`)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + *PFQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + %zY5'$v `
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' x<rS2d-Y
FROM sysfiles P~lU`.X}
WHERE name = @LogicalFileName `S4*~Xx
DROP TABLE DummyTrans 3:#6/@wQ
SET NOCOUNT OFF sqV~Dw
8、说明:更改某个表 hg<[@Q%$o
exec sp_changeobjectowner 'tablename','dbo' BUsxgs"),
9、存储更改全部表 ; }T+ImjA
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch {0+WVZ4u
@OldOwner as NVARCHAR(128), pQc-}o"
@NewOwner as NVARCHAR(128) {"$[MYi:
AS C GK]i.N
DECLARE @Name as NVARCHAR(128) >L "+8N6
DECLARE @Owner as NVARCHAR(128) C,mfA%63
DECLARE @OwnerName as NVARCHAR(128) ..BP-N)V)
DECLARE curObject CURSOR FOR `s+kYWg'Z
select 'Name' = name, `Xeiz'~f8
'Owner' = user_name(uid) =E!Y f#p+q
from sysobjects cl4_M{~
where user_name(uid)=@OldOwner (`#z@,1
order by name :t "_I
OPEN curObject 9(!AKKrr;
FETCH NEXT FROM curObject INTO @Name, @Owner hP.Km%C)0n
WHILE(@@FETCH_STATUS=0) s3@mk\?qMe
BEGIN P4{~fh (
if @Owner=@OldOwner "Lk BN0D
begin b+arnKo1fk
set @OwnerName = @OldOwner + '.' + rtrim(@Name) .I#_~C'\
exec sp_changeobjectowner @OwnerName, @NewOwner iWA?FBv
end gxUa-R
-- select @name,@NewOwner,@OldOwner 'xnI Nu
FETCH NEXT FROM curObject INTO @Name, @Owner 7 p!ROl^
END `J03t\
close curObject n q>F_h
deallocate curObject ?tqJkL#
GO uF}B:53A
10、SQL SERVER中直接循环写入数据 za 7+xF
declare @i int z6B#F<h
set @i=1 W)T'?b'.
while @i<30 b]xoXC6@ t
begin KkpbZ7\@
insert into test (userid) values(@i) >O
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set @i=@i+1 (@!K tW
end d@a<Eq
小记存储过程中经常用到的本周,本月,本年函数 `s
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Dateadd(wk,datediff(wk,0,getdate()),-1) HIE8@Rv/3
Dateadd(wk,datediff(wk,0,getdate()),6) a(?)r[=
Dateadd(mm,datediff(mm,0,getdate()),0) ?GhMGpdMq
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ?D)$OCS
Dateadd(yy,datediff(yy,0,getdate()),0) :IJ<Mmb
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |`o1B;lc
上面的SQL代码只是一个时间段 1+7_L`SB
Dateadd(wk,datediff(wk,0,getdate()),-1) 0&Ftx%6%
Dateadd(wk,datediff(wk,0,getdate()),6) 3< 6h~ek)
就是表示本周时间段. 6:; >id${
下面的SQL的条件部分,就是查询时间段在本周范围内的: LCj3{>{/=
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) /5L\:eX%
而在存储过程中 ?mK&Slh.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 3pW4Ul@e
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) H-u
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