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。 CMG`'gT
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一、基础 @H# kvYWmn
1、说明:创建数据库 4Ig{#}<
CREATE DATABASE database-name {O&liU4
2、说明:删除数据库 LjQ1ar\
drop database dbname hL{B9?
3、说明:备份sql server vK.4JOlRF
--- 创建 备份数据的 device Ah>krE0t
USE master 4^NHf|UJH
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' "0 PN
--- 开始 备份 np\Q&
BACKUP DATABASE pubs TO testBack 7}1Kafs
4、说明:创建新表 +heS\I_Mp
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) sV'.Bomq
根据已有的表创建新表: '
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A:create table tab_new like tab_old (使用旧表创建新表) CG>2,pP,
B:create table tab_new as select col1,col2... from tab_old definition only &N7:k+E
5、说明:删除新表 3F'dT[;
drop table tabname ?a0}^:6
6、说明:增加一个列 +e]b,9.sR
Alter table tabname add column col type 8}#Lo9:,d
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。 ylxfh(
7、说明:添加主键: Alter table tabname add primary key(col) }.$B1%2
说明:删除主键: Alter table tabname drop primary key(col) -0r"#48(%
8、说明:创建索引:create [unique] index idxname on tabname(col....) E)_!Hi0<s
删除索引:drop index idxname =+-.5M
注:索引是不可更改的,想更改必须删除重新建。 P[P72WR
9、说明:创建视图:create view viewname as select statement So 6cm|{
删除视图:drop view viewname cf!k
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10、说明:几个简单的基本的sql语句 Cm}UWX
选择:select * from table1 where 范围 &CmkNm_B
插入:insert into table1(field1,field2) values(value1,value2) @"0N @gU
删除:delete from table1 where 范围 K<w5[E9V.
更新:update table1 set field1=value1 where 范围 Q|<?$.FN"8
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! VaIP
排序:select * from table1 order by field1,field2 [desc] ` dUiz5o'
总数:select count as totalcount from table1 S2
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求和:select sum(field1) as sumvalue from table1 ;Kq?*H
平均:select avg(field1) as avgvalue from table1 -Us% g
最大:select max(field1) as maxvalue from table1 }~CZqIP
最小:select min(field1) as minvalue from table1 x0;}b-f
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11、说明:几个高级查询运算词 JHZo:Ad -&
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A: UNION 运算符 %+!9
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。 e&4wwP"`<
B: EXCEPT 运算符 Qn3+bF4
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。 x15tQb+
C: INTERSECT 运算符 r~2@#gTbl
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。 ZznWs+
注:使用运算词的几个查询结果行必须是一致的。 kZ[yv
12、说明:使用外连接 Ng39D#_)
A、left outer join: &q}@[
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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。 BBJ]>lQ
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 <r`Jn49
B:right outer join:
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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。 jTgh+j]AP
C:full outer join: ;<@O^_+
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。 yaYt/?|
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二、提升 *-LU'yM6Yh
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 'htA! KHF
法一:select * into b from a where 1<>1 q<uLBaL_]r
法二:select top 0 * into b from a <~X6D?
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +<WT$ddK=5
insert into b(a, b, c) select d,e,f from b; KR(ftG'
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) d>98 E9
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 1p<?S}zg@
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. :tG".z
4、说明:子查询(表名1:a 表名2:b) K y2xWd8
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) gq1Y]t|4F
5、说明:显示文章、提交人和最后回复时间 1WN93SQ=
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b L Hz<=]?@
6、说明:外连接查询(表名1:a 表名2:b) W}_}<rlF
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {-`OE
7、说明:在线视图查询(表名1:a ) /)4r2 x
select * from (SELECT a,b,c FROM a) T where t.a > 1; )tch>.EQ_
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 i4r~eneP
select * from table1 where time between time1 and time2 ^JDV4>S\
select a,b,c, from table1 where a not between 数值1 and 数值2 SW'KYzn
9、说明:in 的使用方法 <d`UifqD
select * from table1 where a [not] in ('值1','值2','值4','值6') 6i9I 4*'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 2^M+s\p
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) oP75|p
11、说明:四表联查问题: jtr=8OiL
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... {$:13AnK
12、说明:日程安排提前五分钟提醒 "FIx^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 '|?r&-5 h
13、说明:一条sql 语句搞定数据库分页 D?F5o^e"h<
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 2`U&,,-Mf
14、说明:前10条记录 ,VsCRp
select top 10 * form table1 where 范围 13kb~'+&r
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.) QaBXzf
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) XJ?z{gXJ
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 r8>?-P
(select a from tableA ) except (select a from tableB) except (select a from tableC) '="){
17、说明:随机取出10条数据 @}!$NI8
select top 10 * from tablename order by newid() kDa#yN\
18、说明:随机选择记录 +r P<m
select newid() B:.;:AEbT
19、说明:删除重复记录 Ud*[2Oi|R
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) B9:0|i!!A`
20、说明:列出数据库里所有的表名 |?=1tS{iT
select name from sysobjects where type='U'
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21、说明:列出表里的所有的 K3D $
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select name from syscolumns where id=object_id('TableName') '+zsj0!A
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。 Jz0S2&
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 tp2 _OQAQ
显示结果: o9\m?~g!E
type vender pcs P`"DepeD
电脑 A 1 <F
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电脑 A 1 'B6H/d>
光盘 B 2 +[[gU;U"v
光盘 A 2 hzo,.hS's
手机 B 3 ,peE'
手机 C 3 Bys|i 0tb-
23、说明:初始化表table1 GTNTx5H
TRUNCATE TABLE table1 OR8o%AxL7
24、说明:选择从10到15的记录 2Hwf:S'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc a8aqcDs>O
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三、技巧 ?EAqv]
1、1=1,1=2的使用,在SQL语句组合时用的较多 (Z +C
"where 1=1" 是表示选择全部 "where 1=2"全部不选, /U]5#'i
如: dD<kNa}2
if @strWhere !='' IpmREl$j
begin W%cPX0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere b7j#a#
end d6&tz!f
else 9Wrclai
begin 0pOha(,~
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `VN<6o(
end nCB3d[/B
我们可以直接写成 *?fBmq[j
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^dD?riFAk
2、收缩数据库 gMn)<u >
--重建索引 jQ}|]pj+
DBCC REINDEX >WX'oP(<
DBCC INDEXDEFRAG mIodD)?{
--收缩数据和日志 ~vFo 0k(
DBCC SHRINKDB tH(#nx8
DBCC SHRINKFILE ,-kZ5&r
3、压缩数据库 /WVMT]T6^,
dbcc shrinkdatabase(dbname) t%@pyK
4、转移数据库给新用户以已存在用户权限 N2J!7uoQ
exec sp_change_users_login 'update_one','newname','oldname' `,[c??h
go -',Y;0b%
5、检查备份集 h %S#+t(Bf
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -wRzMT19MG
6、修复数据库 6suc:rp";
ALTER DATABASE [dvbbs] SET SINGLE_USER 7Y:s6 R|
GO N> Y3[G+
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK IRa*}MJe
GO W0kq>s4
ALTER DATABASE [dvbbs] SET MULTI_USER ?]N&H90^5
GO Q-5wI$=
7、日志清除
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SET NOCOUNT ON t+ ]+Gn
DECLARE @LogicalFileName sysname, DmsloPB?_
@MaxMinutes INT, qW^l2Jff
@NewSize INT th,qq
USE tablename -- 要操作的数据库名 ^5}3FvW
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. H(s^le:!
@NewSize = 1 -- 你想设定的日志文件的大小(M) o+&sodt|`
-- Setup / initialize Qafg/JU
DECLARE @OriginalSize int b87o6"j
SELECT @OriginalSize = size w"|c;E1;_
FROM sysfiles >0oc=9H8
WHERE name = @LogicalFileName b}*hodzF
SELECT 'Original Size of ' + db_name() + ' LOG is ' + f *vziC<m
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + LBB[aF,Lr
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' v%^H9aK_
FROM sysfiles `( Gk_VAa
WHERE name = @LogicalFileName fHi+PEbR
CREATE TABLE DummyTrans PV2904
(DummyColumn char (8000) not null) *TkABUL
DECLARE @Counter INT, f?6=H^_>
@StartTime DATETIME, bX1ip2X
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@TruncLog VARCHAR(255) FC#Qtu~J
SELECT @StartTime = GETDATE(), }I]q$3.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' =fPO0Ot;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) (%Rs&/vU~
EXEC (@TruncLog) ~fe0Ba4
-- Wrap the log if necessary. 3Y8
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Z#04 ]
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Tw5BvB1
AND (@OriginalSize * 8 /1024) > @NewSize 4r*6fJ*bJ
BEGIN -- Outer loop. cS"6%:hQ
SELECT @Counter = 0 76/%Py|
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) , +^db)
BEGIN -- update OHw6#N$\
INSERT DummyTrans VALUES ('Fill Log') 9'M_t Mm5
DELETE DummyTrans I j /J
SELECT @Counter = @Counter + 1 =g:\R$lQ
END iVcBD0 q)
EXEC (@TruncLog) X1"nq]chGy
END iDsjIW\j
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9^tyjX2
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + nDvWOt
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N.?Wev{
FROM sysfiles Tp7?:YY|
WHERE name = @LogicalFileName .(-3L9T}
DROP TABLE DummyTrans W=*\4B]
SET NOCOUNT OFF ^BZdR<;
8、说明:更改某个表 n|.;g!QDA
exec sp_changeobjectowner 'tablename','dbo' C0M{zGT>}
9、存储更改全部表 jX%Q
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch .+<K-'&=
@OldOwner as NVARCHAR(128), {`LV{!
@NewOwner as NVARCHAR(128) BG"6jQh
AS
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DECLARE @Name as NVARCHAR(128) e(^O8
DECLARE @Owner as NVARCHAR(128) D<`X
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DECLARE @OwnerName as NVARCHAR(128) yT4|eHl
DECLARE curObject CURSOR FOR VWi-)
select 'Name' = name, |8B[yr.b
'Owner' = user_name(uid) 3]i1M%'i
from sysobjects y[cAU:P?
where user_name(uid)=@OldOwner >7|37a
order by name = U5)m
OPEN curObject Dz?F,g_
FETCH NEXT FROM curObject INTO @Name, @Owner _?ym,@}#
WHILE(@@FETCH_STATUS=0) Z+?j8(:n
BEGIN MAXdgL[]
if @Owner=@OldOwner Z8 x(_ft5
begin G9
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) }7V/(K
exec sp_changeobjectowner @OwnerName, @NewOwner ]O[f#lG
end sYz:(hZS
-- select @name,@NewOwner,@OldOwner ]mp.KvB
FETCH NEXT FROM curObject INTO @Name, @Owner __QTlj
END KH;e)91
close curObject eR/7*G5
deallocate curObject ^%L$$V
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GO 3eB2=_V`
10、SQL SERVER中直接循环写入数据 Y9WH%
declare @i int Gi-tf<
set @i=1 ?}y7S]B FI
while @i<30 ()rDM@
begin |
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insert into test (userid) values(@i) pO^
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set @i=@i+1 l6&R
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end U5klVl
小记存储过程中经常用到的本周,本月,本年函数 #&2mu
Dateadd(wk,datediff(wk,0,getdate()),-1) DeUDZL%/
Dateadd(wk,datediff(wk,0,getdate()),6) T<OLfuV
Dateadd(mm,datediff(mm,0,getdate()),0)
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) dL"v*3Fy
Dateadd(yy,datediff(yy,0,getdate()),0) 4avM:h
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) j_}e%,}
上面的SQL代码只是一个时间段 dCHU* 7DS
Dateadd(wk,datediff(wk,0,getdate()),-1) cX*^PSM
Dateadd(wk,datediff(wk,0,getdate()),6) u^ T2
就是表示本周时间段. NYCkYI
下面的SQL的条件部分,就是查询时间段在本周范围内的: . "R
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Z'EZ PuZ!'
而在存储过程中 yY1&hop
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) sB6UlX;b:
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {M=tw