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。 e"#QUc(
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一、基础 h*
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1、说明:创建数据库 ^>Vl@cW0uz
CREATE DATABASE database-name s(Y2]X4
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2、说明:删除数据库 $E/N
drop database dbname }~NM\rm
3、说明:备份sql server C5Vlqc;
--- 创建 备份数据的 device
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USE master V15/~
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^(kmF UV,Z
--- 开始 备份 w#v-h3XcF
BACKUP DATABASE pubs TO testBack ?K\r-J!Y
4、说明:创建新表 ZH)Jq^^RI
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ^HhV?Iqg
根据已有的表创建新表: lvAKL>qX
A:create table tab_new like tab_old (使用旧表创建新表) E3LEeXcLS
B:create table tab_new as select col1,col2... from tab_old definition only .oS[ DTn5S
5、说明:删除新表 &w!(.uDO
drop table tabname e0<Wed
6、说明:增加一个列 u>ZH-nw O
Alter table tabname add column col type F MX^k
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 y(ceEV
7、说明:添加主键: Alter table tabname add primary key(col) 23d*;ri5
说明:删除主键: Alter table tabname drop primary key(col) E-jJ!>&K
8、说明:创建索引:create [unique] index idxname on tabname(col....) jl>jy6T
删除索引:drop index idxname 0fGt7 "Q
注:索引是不可更改的,想更改必须删除重新建。 s%QCdU ]
9、说明:创建视图:create view viewname as select statement tWyl&,3?1
删除视图:drop view viewname oeYUsnsbi
10、说明:几个简单的基本的sql语句 2=
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选择:select * from table1 where 范围 cYgd1
插入:insert into table1(field1,field2) values(value1,value2) ' hDs.Wnu
删除:delete from table1 where 范围 CKnPMvmz
更新:update table1 set field1=value1 where 范围 _z=ytt9D
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! YEa<zhO8
排序:select * from table1 order by field1,field2 [desc] B/*\Ih9y
总数:select count as totalcount from table1 9Y:Iha`$w
求和:select sum(field1) as sumvalue from table1 L\hid/NL
平均:select avg(field1) as avgvalue from table1 W(}2R>$
最大:select max(field1) as maxvalue from table1 w~C\5 i
最小:select min(field1) as minvalue from table1 -x{@D{Q%
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11、说明:几个高级查询运算词 C{:U<q
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A: UNION 运算符 I5*<J n
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。 m\oxS;fxWi
B: EXCEPT 运算符 ;m=k
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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。 2KlVj]!7
C: INTERSECT 运算符 &^`[$LtYd
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 \sAkKPI
注:使用运算词的几个查询结果行必须是一致的。 d]USk&8
12、说明:使用外连接 !K-qoBqKM
A、left outer join: X$Shi
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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。 N\"Hf=Y(~
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 EQe$~}[
B:right outer join: SdF+b+P]
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 d\R "?Sg
C:full outer join: "/G]M&
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 K]1|#`n
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二、提升 m
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 27i-B\r
法一:select * into b from a where 1<>1 l_s#7 .9$
法二:select top 0 * into b from a x~i\*Ox^
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) DS+BX`i%#p
insert into b(a, b, c) select d,e,f from b; _FNW[V
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) OHwH(}H?
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 D9 Mst6
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ~W-l|-eogz
4、说明:子查询(表名1:a 表名2:b) f%3MDI
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''EF';
5、说明:显示文章、提交人和最后回复时间 1,Es'
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Ey.%:
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6、说明:外连接查询(表名1:a 表名2:b) KjMwrMgC
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<P&|RTZ
7、说明:在线视图查询(表名1:a ) qm<-(Qc(W
select * from (SELECT a,b,c FROM a) T where t.a > 1; R|k:8v{V=
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 P v=]7>e
select * from table1 where time between time1 and time2 f9OY>|a9
select a,b,c, from table1 where a not between 数值1 and 数值2 Y[|9
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9、说明:in 的使用方法 ahdwoB
select * from table1 where a [not] in ('值1','值2','值4','值6') 2%v6h
10、说明:两张关联表,删除主表中已经在副表中没有的信息 p' 6h9/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 6B]i}nFH{+
11、说明:四表联查问题: f,kV
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 ..... gL~3z'$
12、说明:日程安排提前五分钟提醒 $VjMd f
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 1Q=L/keP
13、说明:一条sql 语句搞定数据库分页 r:PYAb=g
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 &1Y7Ne
14、说明:前10条记录 uJ=d!Kn
select top 10 * form table1 where 范围 WZn"I&Z
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ~1XC5.*-
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b)
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 z0x^HDAeC
(select a from tableA ) except (select a from tableB) except (select a from tableC) ^?_MIS`4N
17、说明:随机取出10条数据 (/^?$~m"
select top 10 * from tablename order by newid() S'`G7ht
18、说明:随机选择记录 |'lNR)5
select newid() E^Ch;)j|
19、说明:删除重复记录 mN
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 03AQB;.
20、说明:列出数据库里所有的表名 3s?ZyQy
select name from sysobjects where type='U' 2s=zT5
21、说明:列出表里的所有的 GDs/U1[*
select name from syscolumns where id=object_id('TableName') 0eKLp8;Lh
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。 @NiLKcL#
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 \Unawv~
显示结果: 8QMMKOui\
type vender pcs <Qr*!-Kc6
电脑 A 1 elR1NhB|p
电脑 A 1 Bp5%&T k
光盘 B 2 t<"`gM^|
光盘 A 2 cuI&Q?+c}
手机 B 3 A6+qS
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手机 C 3 H]*B5Jv~
23、说明:初始化表table1 oGyoU#z#
TRUNCATE TABLE table1 }8ESp3~e_
24、说明:选择从10到15的记录 _+)n}Se
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc mKE'l'9A_
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三、技巧 C8i4z
1、1=1,1=2的使用,在SQL语句组合时用的较多 \),zDO+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, V)4?y9xZv
如: \ KsKb0sM
if @strWhere !='' eA3NyL
begin l: kW|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere GY5JPl
end xOr"3;^
else O>I%O^
begin +3M1^:
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?v-!`J>EF#
end 1FG"Ak}D
我们可以直接写成 @\:@_}Z`_}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere PN=5ICT
2、收缩数据库 c,]fw2
--重建索引 s0CDp"uJY
DBCC REINDEX Z%b1B<u$
DBCC INDEXDEFRAG ]ncK M?'O
--收缩数据和日志 U6o]7j&6
DBCC SHRINKDB 1vAJ(O{-
DBCC SHRINKFILE +;)Xu}
3、压缩数据库 AFeFH.G6Jr
dbcc shrinkdatabase(dbname) o.Bbb=*rZ
4、转移数据库给新用户以已存在用户权限 D(&Zq7]n
exec sp_change_users_login 'update_one','newname','oldname' t8; nP[`
go 6-\'
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5、检查备份集 zGc]*R
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 9
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6、修复数据库 -<AGCiLz
ALTER DATABASE [dvbbs] SET SINGLE_USER /!.]Y8yEH
GO GO*D4<#u
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK In;P33'p
GO XF>!~D
ALTER DATABASE [dvbbs] SET MULTI_USER 5Q:49S47
GO >]A#_p
7、日志清除 >6W #v[
SET NOCOUNT ON #s#BYbF
DECLARE @LogicalFileName sysname, *5 \'$;Rg
@MaxMinutes INT, B/mfm 7
@NewSize INT D(Q]ddUi'
USE tablename -- 要操作的数据库名 b7">IzAe
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 UZ6y3%G3^
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~Y;Z5e=
@NewSize = 1 -- 你想设定的日志文件的大小(M) .]a`-Ofn
-- Setup / initialize m?1r@!/y
DECLARE @OriginalSize int "\]]?&
SELECT @OriginalSize = size eht>4)
FROM sysfiles [ \%a7ji#
WHERE name = @LogicalFileName snNB;hkj
SELECT 'Original Size of ' + db_name() + ' LOG is ' + qP zxP @4
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + jK%Lewq
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $"}[\>e*{
FROM sysfiles _ /Eg_dQ~@
WHERE name = @LogicalFileName kY9$ M8b
CREATE TABLE DummyTrans >5TXLOYZ
(DummyColumn char (8000) not null) )4hA Fy6l
DECLARE @Counter INT, )nq(XM7
@StartTime DATETIME, :22wq{
@TruncLog VARCHAR(255) %h;1}SFl0
SELECT @StartTime = GETDATE(), 'Q=(1a11
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' b/\l\\$-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3<[q>7X
EXEC (@TruncLog) m( %PZ*s
-- Wrap the log if necessary. (/9 erfuJ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired PsS.lhj0"
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) -a"b:Q
AND (@OriginalSize * 8 /1024) > @NewSize (^_INy*
BEGIN -- Outer loop. 2T@?&N^OD
SELECT @Counter = 0 r gi4>
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) R((KAl]dL
BEGIN -- update i=hA. y`
INSERT DummyTrans VALUES ('Fill Log') -6X+:r`>u
DELETE DummyTrans zz<o4bR
SELECT @Counter = @Counter + 1 et(AO)uv6
END " ub0}p4V
EXEC (@TruncLog) MUCes3YJH
END (\wV)c9
SELECT 'Final Size of ' + db_name() + ' LOG is ' + [M:<!QXw
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + >svx
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 1zCgPiAem
FROM sysfiles CHjm7
WHERE name = @LogicalFileName ~zvZK]JoX
DROP TABLE DummyTrans YUyYVi7clq
SET NOCOUNT OFF vIZFI
8、说明:更改某个表 0HQTe>!
exec sp_changeobjectowner 'tablename','dbo' b&d4(dk
9、存储更改全部表 *iyc,f^w
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |TF6&$>d
@OldOwner as NVARCHAR(128), -q
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@NewOwner as NVARCHAR(128) 0,8RA_Ca}
AS C~nL3w
DECLARE @Name as NVARCHAR(128) 3{Zd<JYg4-
DECLARE @Owner as NVARCHAR(128) \J;]g\&I"
DECLARE @OwnerName as NVARCHAR(128) &IsPqO
DECLARE curObject CURSOR FOR ~jz51[{v
select 'Name' = name, rZ.z!10
'Owner' = user_name(uid) o,?h}@
from sysobjects x cZF_elt7
where user_name(uid)=@OldOwner ,E@}=x9p
order by name N] pw7S%
OPEN curObject K!2%8Ej,J
FETCH NEXT FROM curObject INTO @Name, @Owner w6-<HPW<S
WHILE(@@FETCH_STATUS=0) |0X~D}r|J
BEGIN !\OX}kHX5
if @Owner=@OldOwner *_HF %JYMZ
begin WA*1_
set @OwnerName = @OldOwner + '.' + rtrim(@Name) M!%|IKw
exec sp_changeobjectowner @OwnerName, @NewOwner -3m!970
end uU-1;m#N?
-- select @name,@NewOwner,@OldOwner afu!.}4Ct
FETCH NEXT FROM curObject INTO @Name, @Owner |1e//*
END }KNBqPo4B
close curObject &]A0=h2{P*
deallocate curObject MlW*Tugg
GO WZP1g kX&M
10、SQL SERVER中直接循环写入数据 b?,=|H
declare @i int QNx xW2+
set @i=1 K(P.i^k
while @i<30 Ht]O:io`
begin 5v=e(Ph+
insert into test (userid) values(@i) @Q&k6.{4Z
set @i=@i+1 e nw*[D !
end g+(Y)9h&
小记存储过程中经常用到的本周,本月,本年函数 g'2;///
Dateadd(wk,datediff(wk,0,getdate()),-1) F%O+w;J4
Dateadd(wk,datediff(wk,0,getdate()),6) <,U$Y>
Dateadd(mm,datediff(mm,0,getdate()),0) FMWM:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Fr (;C>
Dateadd(yy,datediff(yy,0,getdate()),0) 8kE3\#);\
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) l?Ibq} [~
上面的SQL代码只是一个时间段 7?);wh 7`
Dateadd(wk,datediff(wk,0,getdate()),-1) C9,Uwz<!]
Dateadd(wk,datediff(wk,0,getdate()),6) M~+DxnJ=
就是表示本周时间段. R D?52\
下面的SQL的条件部分,就是查询时间段在本周范围内的:
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) $s 'n]]Wq
而在存储过程中 g8"H{u
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) JBLh4c3
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) C5e;U