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。 j*5IRzK1%0
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一、基础 :\vs kk),
1、说明:创建数据库 sO`
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CREATE DATABASE database-name n>?D-)g
2、说明:删除数据库 +SR{FF
drop database dbname S3:AitGJ
3、说明:备份sql server d=n@#|3
--- 创建 备份数据的 device Kv(R|d6Lp
USE master
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~ ;LzTL
--- 开始 备份 'f!U[Qatg
BACKUP DATABASE pubs TO testBack NJ)Dw`|%|)
4、说明:创建新表 ~ney~Pz_
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) x ZP*%yM
根据已有的表创建新表: +Q[uq!<VJk
A:create table tab_new like tab_old (使用旧表创建新表) f-G)pHm
B:create table tab_new as select col1,col2... from tab_old definition only #R{>@]x`
5、说明:删除新表 3*&
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drop table tabname h~m,0nGO
6、说明:增加一个列 )Xh}N
Alter table tabname add column col type y?&hA!x
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。 ~\mh\a&
7、说明:添加主键: Alter table tabname add primary key(col) i1|>JM[V
说明:删除主键: Alter table tabname drop primary key(col) .G8>UXX
8、说明:创建索引:create [unique] index idxname on tabname(col....) K
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删除索引:drop index idxname 6q\*{_CPB
注:索引是不可更改的,想更改必须删除重新建。 8f/KNh7#s
9、说明:创建视图:create view viewname as select statement z7ik/>d?
删除视图:drop view viewname _Z Sp$>)/
10、说明:几个简单的基本的sql语句 t|$jgM
选择:select * from table1 where 范围 Lxwi"ndP
插入:insert into table1(field1,field2) values(value1,value2) +U2lwd!j
删除:delete from table1 where 范围 "~5cz0
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更新:update table1 set field1=value1 where 范围 P{--R\
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! HJ]xZ83pC
排序:select * from table1 order by field1,field2 [desc] |L8
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总数:select count as totalcount from table1 V2ih/mh
求和:select sum(field1) as sumvalue from table1 !,$#i
平均:select avg(field1) as avgvalue from table1 uYMn VE"
最大:select max(field1) as maxvalue from table1 Xj
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最小:select min(field1) as minvalue from table1 c1"wS*u
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11、说明:几个高级查询运算词 F#gA2VCm
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A: UNION 运算符 rXi&8R[
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。 [zx|3wWAX-
B: EXCEPT 运算符 l S)^8
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。 {+WBi(=W
C: INTERSECT 运算符 w6i2>nu_O
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。 ryVYY>*(K
注:使用运算词的几个查询结果行必须是一致的。 b^VRpv
12、说明:使用外连接 nwU],{(Hgr
A、left outer join: |Dn Zk3M,
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。 ZC N}iQu4
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 [(heE
B:right outer join: %dzt'uz
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。 TP
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C:full outer join: NX&dJ
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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。 He(65ciT<O
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二、提升 i%-yR DIX
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Q>, &@
法一:select * into b from a where 1<>1 z2iMpZ
法二:select top 0 * into b from a gx.\H3y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) In1W/?
insert into b(a, b, c) select d,e,f from b; ;OlnIxH(W
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) 1'qXT{f/~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ~.:{
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. :C*}Yg
4、说明:子查询(表名1:a 表名2:b) ]E-/}Ysz
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) ^OKm (
5、说明:显示文章、提交人和最后回复时间 f~NS{gL*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b J8emz8J
6、说明:外连接查询(表名1:a 表名2:b) N1Vj;-
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c A0<g8pv
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; k|/VNV( =0
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 ',r` )9o
select * from table1 where time between time1 and time2 ,{PN6B
select a,b,c, from table1 where a not between 数值1 and 数值2 f'oTN!5WF
9、说明:in 的使用方法 g{V(WyT@
select * from table1 where a [not] in ('值1','值2','值4','值6') ?>;aD
10、说明:两张关联表,删除主表中已经在副表中没有的信息 FOQ-KP\=,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) WqA)V,E
11、说明:四表联查问题: TRi'l #m4
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 ..... ,Vi_~b
12、说明:日程安排提前五分钟提醒 6TW<,SM
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]`$6=)_X
13、说明:一条sql 语句搞定数据库分页 d_25]B(
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 $`|hF[tv
14、说明:前10条记录 C~h#pAh
select top 10 * form table1 where 范围 Qn$'bK2V
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.) \6wltTW]#
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) @rYZ0`E9
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 +j 9+~
(select a from tableA ) except (select a from tableB) except (select a from tableC) N|yA]dg[
17、说明:随机取出10条数据 VeWh9:"bJ
select top 10 * from tablename order by newid() *:CTIV5N0
18、说明:随机选择记录 !igPyhi,hl
select newid() @&m [w'tn
19、说明:删除重复记录 NPH(v`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) FEk9a^Xyx
20、说明:列出数据库里所有的表名 rN&fFI
select name from sysobjects where type='U' ^aB;Oo
21、说明:列出表里的所有的 g$uiwqNA%
select name from syscolumns where id=object_id('TableName') wO,qFY
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。 +S~ u ,=
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 { 4j<X5V
显示结果: ^UvL1+
type vender pcs ~!({Unt+'
电脑 A 1 8WytvwB}
电脑 A 1 2U[/"JL
光盘 B 2 >)WE3PT/O"
光盘 A 2 u.2X"
手机 B 3 k{f1q>gd
手机 C 3 f!+d*9
23、说明:初始化表table1 x<l 5wh
TRUNCATE TABLE table1 WfO E I1
24、说明:选择从10到15的记录 z -?\b^
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^VYR}1Mw
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三、技巧 16Qu{K
1、1=1,1=2的使用,在SQL语句组合时用的较多 )j8'6tk)Z
"where 1=1" 是表示选择全部 "where 1=2"全部不选, oc"p5Y3,Os
如: Zna6-0o
if @strWhere !='' ~;HASHu
begin ?*~
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [\ku,yd%0
end \;-Yz
else niS\0ZA
begin YMw,C:a4
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 4m\Cc_:jO
end @lzq`SzM
我们可以直接写成 1jx?zvE,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere OFohyy(
2、收缩数据库 $~8gh>`]
--重建索引 CZzt=9
DBCC REINDEX dU-:#QV6
DBCC INDEXDEFRAG w_U#z(W3l
--收缩数据和日志 W
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DBCC SHRINKDB S8v,'Cc
DBCC SHRINKFILE |Gq3pL<jkC
3、压缩数据库 _oZ3n2v}@
dbcc shrinkdatabase(dbname) !IJ
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4、转移数据库给新用户以已存在用户权限 r`ftflNh(
exec sp_change_users_login 'update_one','newname','oldname' n'ZPB
go P=}l.R*1G
5、检查备份集 i{}m 8K)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3x(Y+
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6、修复数据库 bSTori5
ALTER DATABASE [dvbbs] SET SINGLE_USER .\`MoH
GO tuH#Cy
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK BHpay
GO &4wSX{c/P
ALTER DATABASE [dvbbs] SET MULTI_USER +sx(q@
GO &(<Gr0
7、日志清除 "X<V>q$0~c
SET NOCOUNT ON 9F3aT'3#!
DECLARE @LogicalFileName sysname, #F/W_G7 v
@MaxMinutes INT, Fp B3SJ6 B
@NewSize INT klmbbLce
USE tablename -- 要操作的数据库名 Cno[:iom
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 uaD+G:{[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. aAcQmq TT
@NewSize = 1 -- 你想设定的日志文件的大小(M) yodhDSO5i
-- Setup / initialize UChLWf|'
DECLARE @OriginalSize int *r4FOA%P
SELECT @OriginalSize = size hAgrs[OFj
FROM sysfiles \`8$bpW[nS
WHERE name = @LogicalFileName &|IO+'_
SELECT 'Original Size of ' + db_name() + ' LOG is ' + bz:En'2>F
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + oVl:g:K40
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' An]Vx<PD
FROM sysfiles -R9{Ak
WHERE name = @LogicalFileName )1R[~]y
CREATE TABLE DummyTrans MHE/#G
(DummyColumn char (8000) not null) <&+0[9x
DECLARE @Counter INT, de8xl
@StartTime DATETIME, >8NUji2I
@TruncLog VARCHAR(255) S!-t{Q+j^
SELECT @StartTime = GETDATE(), O>*Vo!z\f
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *"jlsI
DBCC SHRINKFILE (@LogicalFileName, @NewSize) p*jH5h cy
EXEC (@TruncLog) r{*Qsaw
-- Wrap the log if necessary. bz1`f >%l
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 'Q*.[aJt
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 2*W|s7cc
AND (@OriginalSize * 8 /1024) > @NewSize uKY1AC__
BEGIN -- Outer loop. L{ej<0 yr
SELECT @Counter = 0 CT\rx>[J.6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) s4Jy96<
BEGIN -- update W T @XHwt
INSERT DummyTrans VALUES ('Fill Log') 4U$M0 =
DELETE DummyTrans OHY|< &*
SELECT @Counter = @Counter + 1 \"I418T K
END 9qq6P!
EXEC (@TruncLog) ;5|d[r}k3
END p;%5 o0{1
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ow+_g R-
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + D3tcwjXoW_
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Qp@}v7Due
FROM sysfiles O*F= xG
WHERE name = @LogicalFileName N+]HJ`K
DROP TABLE DummyTrans 6 {`J I
SET NOCOUNT OFF FrRUAoFO
8、说明:更改某个表 A(XX2f!i
exec sp_changeobjectowner 'tablename','dbo' 29z@ !
9、存储更改全部表 XB[EJGaX
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch B$q5/ L$}
@OldOwner as NVARCHAR(128), DLq'V.M:
@NewOwner as NVARCHAR(128) .5~3D97X&
AS Eg4&D4TGp
DECLARE @Name as NVARCHAR(128) Q*f0YjH!
DECLARE @Owner as NVARCHAR(128) Rto/-I0l
DECLARE @OwnerName as NVARCHAR(128) ~1Ffu x
DECLARE curObject CURSOR FOR ZlMS=<hgFx
select 'Name' = name, 6m:$RW
'Owner' = user_name(uid) u3cl7~- yW
from sysobjects on7?V<
where user_name(uid)=@OldOwner l>oJ^J
order by name ErQGVE;zk
OPEN curObject
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FETCH NEXT FROM curObject INTO @Name, @Owner 7 /"Z/^
WHILE(@@FETCH_STATUS=0) *I9O63
BEGIN nWd;XR6|
if @Owner=@OldOwner z@<jZM
begin F$s:\N
set @OwnerName = @OldOwner + '.' + rtrim(@Name) OJFWmZ(X
exec sp_changeobjectowner @OwnerName, @NewOwner $7O3+R/=
end ~A(^<
-- select @name,@NewOwner,@OldOwner pCeCR
FETCH NEXT FROM curObject INTO @Name, @Owner n"I{aJ]K
END j\@&poJ(,
close curObject <pFbm
deallocate curObject xjYH[PgfX
GO O^~nf%
10、SQL SERVER中直接循环写入数据 a0k/R<4
declare @i int MbQ%'z6D
set @i=1 WQ{^+C9g'1
while @i<30 {(d 6of`C_
begin (V}?y:)
insert into test (userid) values(@i) )ItW}1[I
set @i=@i+1 xd`\Ai
end 7<*g'6JG[
小记存储过程中经常用到的本周,本月,本年函数 |lIgvHgg
Dateadd(wk,datediff(wk,0,getdate()),-1) NiVZ=wEp,
Dateadd(wk,datediff(wk,0,getdate()),6) U]M5&R=?
Dateadd(mm,datediff(mm,0,getdate()),0) a3[,3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Eh *u6K)Z
Dateadd(yy,datediff(yy,0,getdate()),0) k]c$SzJ> /
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Gg^gK*D
上面的SQL代码只是一个时间段 pe!"!xJE
Dateadd(wk,datediff(wk,0,getdate()),-1) R$2\Xl@qQF
Dateadd(wk,datediff(wk,0,getdate()),6) ;Yt'$D*CP
就是表示本周时间段. `@&WELFv{
下面的SQL的条件部分,就是查询时间段在本周范围内的: GCrsf
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) EO/TuKt
而在存储过程中 ,H/BW`rL]#
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) N.V5>2
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $b) k