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。 >JC
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一、基础 (K)] qNH
1、说明:创建数据库 Te<}*qvD
CREATE DATABASE database-name OslL~<
2、说明:删除数据库 JU^lyi!
drop database dbname ]Zyur`
3、说明:备份sql server dAkgR~
--- 创建 备份数据的 device @jsDq
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USE master (?(zH3
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' =Q+=
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--- 开始 备份 `O[};3O&
BACKUP DATABASE pubs TO testBack =1 Oj*x@*4
4、说明:创建新表 eFL=G%
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) xx{PespNt
根据已有的表创建新表: O4^8jK}
A:create table tab_new like tab_old (使用旧表创建新表) t ]_VG
B:create table tab_new as select col1,col2... from tab_old definition only Pyb Z)5u
5、说明:删除新表 DW_1,:,?7l
drop table tabname }L# _\
6、说明:增加一个列 r0 ,:J
Alter table tabname add column col type MBhWMCN2
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。 BE_ay-
7、说明:添加主键: Alter table tabname add primary key(col) .7.b:Dn0
说明:删除主键: Alter table tabname drop primary key(col) |!"`MIw,
8、说明:创建索引:create [unique] index idxname on tabname(col....) 06N}k<10O
删除索引:drop index idxname !,Va(E|=
注:索引是不可更改的,想更改必须删除重新建。 X@LRsg
9、说明:创建视图:create view viewname as select statement -/ g B|J
删除视图:drop view viewname CJJzCVj
10、说明:几个简单的基本的sql语句 :QB<?HaS'
选择:select * from table1 where 范围 9&` 2V
插入:insert into table1(field1,field2) values(value1,value2) b/{t|io{
删除:delete from table1 where 范围 hR
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更新:update table1 set field1=value1 where 范围 or';A'k
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! i5K[>5
排序:select * from table1 order by field1,field2 [desc] F=a<~EpZ
总数:select count as totalcount from table1 }A7j/uy}s
求和:select sum(field1) as sumvalue from table1 iTAx=SG
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 Ft;^g3N
最小:select min(field1) as minvalue from table1 f'VX Y-
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11、说明:几个高级查询运算词 0^RXGN
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A: UNION 运算符 8_tK4PwP
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。 ` M3w]qJ<}
B: EXCEPT 运算符 P)MDPI+~
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。 elFtBnL'
C: INTERSECT 运算符 */|9= $54
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 I|
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注:使用运算词的几个查询结果行必须是一致的。 #~l(]h@
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12、说明:使用外连接 pt?q#EfFJ
A、left outer join: kAC&S!n
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 (r D_(%o
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c yGPS`S
B:right outer join: ^]a #7/]o
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 P:aJ#
C:full outer join: ek}a}.3 {
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 |]ZYa.+:
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二、提升 ktdW`R\+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0Pe>Es|^A#
法一:select * into b from a where 1<>1 YGPy@-,E
法二:select top 0 * into b from a 2g>SHS@1>
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {'2@(^3
insert into b(a, b, c) select d,e,f from b; Jh?dw3Ai^
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) iIq)~e/ Z
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 %e(z/"M=`
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. dnb)/
4、说明:子查询(表名1:a 表名2:b) mHBnC&-/
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) K/3)g9Z&io
5、说明:显示文章、提交人和最后回复时间 d~`x )B(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b |Clut~G
6、说明:外连接查询(表名1:a 表名2:b) JZD[N Z<
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ]5$eAYq
7、说明:在线视图查询(表名1:a ) !H irhDN
select * from (SELECT a,b,c FROM a) T where t.a > 1; /Ya_>+oo
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 ZOQTINf
select * from table1 where time between time1 and time2 J<dVTxK12
select a,b,c, from table1 where a not between 数值1 and 数值2 :h&fbBH
9、说明:in 的使用方法 7qg{v9|,
select * from table1 where a [not] in ('值1','值2','值4','值6') EVVP]ND
10、说明:两张关联表,删除主表中已经在副表中没有的信息 X'`~s}vGO
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) :SGF45>B@
11、说明:四表联查问题: fbL\?S,w
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 ..... kMOpi =Z1
12、说明:日程安排提前五分钟提醒 'F_8j;
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 oNU0 qZ5
13、说明:一条sql 语句搞定数据库分页 ,XIz?R>;c
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 pSr{>;bN
14、说明:前10条记录 dUF&."pW e
select top 10 * form table1 where 范围 w[!^;#
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.) *IY*yR6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )6Ny1x+
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 `>?ra-
(select a from tableA ) except (select a from tableB) except (select a from tableC) ,Td!|~I|j6
17、说明:随机取出10条数据 sM?MLB\Za
select top 10 * from tablename order by newid() '6xQT-sUih
18、说明:随机选择记录 ;M_o)OS3
select newid() zSSB>D
19、说明:删除重复记录 N\#MwLm
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) KA){''>8
20、说明:列出数据库里所有的表名 z[cyA.
select name from sysobjects where type='U' @:U+9[
21、说明:列出表里的所有的 qZh1`\G
select name from syscolumns where id=object_id('TableName') eXKo.JL
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。 /u0'
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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 t7m>A-I
显示结果: sp5eVAd
type vender pcs 6q]5Es<
电脑 A 1 91q8k=p
电脑 A 1 B:e
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光盘 B 2 Gu'rUo3Do
光盘 A 2 5o6>T!
手机 B 3 %_(H{y_!
手机 C 3 H'LD}\K l
23、说明:初始化表table1 '^Ql]% _
TRUNCATE TABLE table1 E/09hD Q
24、说明:选择从10到15的记录 Mnz!nWhk
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc +\|Iu;w
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三、技巧 CWNx4)ZGw
1、1=1,1=2的使用,在SQL语句组合时用的较多 :^fcC[$K
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 6X\ 2GC9
如: qqu.EE
if @strWhere !='' x,otFp
begin Oer^Rk
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }j^\(2
end sPps q
else ?@6/E<-Z$
begin H.WE6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }>'PT-
end S3@|Q\*r
我们可以直接写成 gCN$}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Cz W:L&t
2、收缩数据库 "d$m@c
--重建索引 m@Qt.4m%g
DBCC REINDEX %<\6TZr
DBCC INDEXDEFRAG 2Y>~k{AN%
--收缩数据和日志 Udc=,yo3Qm
DBCC SHRINKDB z9p05NFH
DBCC SHRINKFILE \T\b NbPn
3、压缩数据库 qt3PXqR7:
dbcc shrinkdatabase(dbname) Hw|AA?,0-
4、转移数据库给新用户以已存在用户权限 !p[9{U->o;
exec sp_change_users_login 'update_one','newname','oldname' RiTa \
go C:uz6i1
5、检查备份集 0z[dlHi
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' d~?X/sJ t
6、修复数据库 S<L.c
ALTER DATABASE [dvbbs] SET SINGLE_USER tU^kQR!
GO eXkujjSw"
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 3VUWX5K?
GO PT^c^{V
ALTER DATABASE [dvbbs] SET MULTI_USER shH~4<15
GO Kv@eI$t5
7、日志清除 oP2fX_v1x
SET NOCOUNT ON .iQT5c
DECLARE @LogicalFileName sysname, /% I7Vc
@MaxMinutes INT, "&/]@)TPz
@NewSize INT }HG#s4
USE tablename -- 要操作的数据库名 ~-#yOu
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7nVRn9Hn
@MaxMinutes = 10, -- Limit on time allowed to wrap log. &I({T`=
@NewSize = 1 -- 你想设定的日志文件的大小(M) ?6k}ii!c
-- Setup / initialize [<,~3oRu
DECLARE @OriginalSize int >z%Q>(F
SELECT @OriginalSize = size 2qHf'
FROM sysfiles HJC(\\~
WHERE name = @LogicalFileName z*a8sr
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 5PIZh<
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + kwud?2E
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 0vGyI>
FROM sysfiles W{5:'9,
WHERE name = @LogicalFileName Qe'g3z>
CREATE TABLE DummyTrans D-U<u@A4
(DummyColumn char (8000) not null) Nk;iiz+_p
DECLARE @Counter INT, <X_!x_x
@StartTime DATETIME, G\;}w
@TruncLog VARCHAR(255) Gs*G<P"
SELECT @StartTime = GETDATE(), m))<!3
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' '>k{tPi.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \#rO!z
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EXEC (@TruncLog) kL90&nP
-- Wrap the log if necessary. e/8z+H^H
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired >m'x8xB=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =9G;PVk|
AND (@OriginalSize * 8 /1024) > @NewSize 3p*-tBOO
BEGIN -- Outer loop. O%f8I'u$
SELECT @Counter = 0 9]>iSG^H
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) M0c9pE
BEGIN -- update m9md|yS
INSERT DummyTrans VALUES ('Fill Log') 3I|3wQ (
DELETE DummyTrans %vO<9fE|1
SELECT @Counter = @Counter + 1 + q''y
END l+wc'=]
EXEC (@TruncLog) DXQi-+?
END Hwm?#6\5
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~JuKV&&}K
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 1j\aH&)GH
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 6<5Jq\-h
FROM sysfiles >?YNW
WHERE name = @LogicalFileName \Xt)E[
DROP TABLE DummyTrans [rreFSy#@
SET NOCOUNT OFF !RlC~^
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8、说明:更改某个表 *o' 4,+=am
exec sp_changeobjectowner 'tablename','dbo' sl/)|~3!8
9、存储更改全部表 #vf_D?^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch `BnP[jF
@OldOwner as NVARCHAR(128), ACjf\4Q
@NewOwner as NVARCHAR(128) /.=r>a}l
AS (_9|w|(
DECLARE @Name as NVARCHAR(128) ^ft]b2i
DECLARE @Owner as NVARCHAR(128) !Zbesp KZ
DECLARE @OwnerName as NVARCHAR(128) m&R"2t_Z
DECLARE curObject CURSOR FOR c-5jYwV
select 'Name' = name, c Cxi{a1uo
'Owner' = user_name(uid) {@r*+~C3
from sysobjects T 4|jz<iK]
where user_name(uid)=@OldOwner }`9`JmNM
order by name mjEs5XCC"
OPEN curObject bj"z8 kP
FETCH NEXT FROM curObject INTO @Name, @Owner j[P8
WHILE(@@FETCH_STATUS=0) FBsn;,3<W
BEGIN XLTD;[jO
if @Owner=@OldOwner =J@`0H"
begin el'j&I
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5a(<%Q
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exec sp_changeobjectowner @OwnerName, @NewOwner h)E|?b_
end St>`p-
-- select @name,@NewOwner,@OldOwner kb|eQtH
FETCH NEXT FROM curObject INTO @Name, @Owner F@hYA
END <{019Oa
close curObject Q
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deallocate curObject JfTfAq]
GO \8"QvC]
10、SQL SERVER中直接循环写入数据 *?8RXer
declare @i int 8Z:Ezg3^
set @i=1 O3!d(dY=_
while @i<30 V:\]cGA{
begin s#lto0b"8
insert into test (userid) values(@i) S!7g)
set @i=@i+1 a{_ KSg
end
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小记存储过程中经常用到的本周,本月,本年函数 p`GWhI?
Dateadd(wk,datediff(wk,0,getdate()),-1) [A_r1g&_
Dateadd(wk,datediff(wk,0,getdate()),6) ozxYH],
Dateadd(mm,datediff(mm,0,getdate()),0) S\|^ULrH
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) n+quSF)
Dateadd(yy,datediff(yy,0,getdate()),0) 6+8mV8{-8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >Zdi5')
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上面的SQL代码只是一个时间段 *mV&K\_
Dateadd(wk,datediff(wk,0,getdate()),-1) l7Lj[d<n
Dateadd(wk,datediff(wk,0,getdate()),6)
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就是表示本周时间段. n{=7 yK
下面的SQL的条件部分,就是查询时间段在本周范围内的: dwp:iM
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 01nsdZ-
而在存储过程中 u&SZlkf6%
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) C*O
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) _:5=|2-E