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。
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一、基础 uFPJ}m[>5
1、说明:创建数据库 yneIY-g(p
CREATE DATABASE database-name 40,u(4.m*
2、说明:删除数据库 k\(LBZ"vR
drop database dbname eT8(O36%
3、说明:备份sql server &("HH"!
--- 创建 备份数据的 device D >ax<t1K
USE master #mu3`,9V
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2_i/ F)W
--- 开始 备份 Sh&n
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BACKUP DATABASE pubs TO testBack 'MZX"t
4、说明:创建新表 ?Pg{nlJvq
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) PNVYW?l
根据已有的表创建新表: anLSD/'4W
A:create table tab_new like tab_old (使用旧表创建新表) b5WtL+Z
B:create table tab_new as select col1,col2... from tab_old definition only z+IHt(
5、说明:删除新表 O*%
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drop table tabname 7;0$UYDU*
6、说明:增加一个列 ,m ^q>
Alter table tabname add column col type .3Ex=aQcX
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ^yLiyR e\
7、说明:添加主键: Alter table tabname add primary key(col) IJX75hE0g
说明:删除主键: Alter table tabname drop primary key(col) YI[y/~!
8、说明:创建索引:create [unique] index idxname on tabname(col....) z*,P^K 0T
删除索引:drop index idxname rBNl%+ sB
注:索引是不可更改的,想更改必须删除重新建。 D}4*Il?
9、说明:创建视图:create view viewname as select statement d@-s_gw
删除视图:drop view viewname g Mhn\
10、说明:几个简单的基本的sql语句 um.s:vj$
选择:select * from table1 where 范围 4rXjso|
插入:insert into table1(field1,field2) values(value1,value2) /;P* ?
删除:delete from table1 where 范围 [fVtQ@-S!
更新:update table1 set field1=value1 where 范围 ,]CZ(q9-
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! oqM(?3 yv
排序:select * from table1 order by field1,field2 [desc] n`'v8 `a]
总数:select count as totalcount from table1 WGy3SV )
求和:select sum(field1) as sumvalue from table1 lM0`yh
平均:select avg(field1) as avgvalue from table1 08*O|Ym,
最大:select max(field1) as maxvalue from table1 m]}%Ag^x
最小:select min(field1) as minvalue from table1 B?o ?LI
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11、说明:几个高级查询运算词 P!uwhha/g
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A: UNION 运算符 9hoTxWpmy
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。 ?[Gj?D.Wc
B: EXCEPT 运算符 ruqx#]-
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。 8&d s
C: INTERSECT 运算符 r7dvj#^
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。 +[W_Jz
注:使用运算词的几个查询结果行必须是一致的。 #L,>)Xk jS
12、说明:使用外连接 5Z
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A、left outer join: gie.K1@|
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。 VE_% /Fs,
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 "XvM1G&s`
B:right outer join: K8>-%ns
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。 "v%|&@
C:full outer join: R
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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。 ^uG^XY&ItC
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二、提升 3RYg-$NK[
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Xgq-r $O2X
法一:select * into b from a where 1<>1 z>n<+tso
法二:select top 0 * into b from a ZAKNyA2
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ykq9]Xqhv
insert into b(a, b, c) select d,e,f from b; 0W}iKT[Z
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) Y@&1[Z
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {R5{v6m_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. >J!J:
4、说明:子查询(表名1:a 表名2:b) Mv\odf\]
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) ,gdf7&r
5、说明:显示文章、提交人和最后回复时间 pxj}%LH
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b BbCt_z'
6、说明:外连接查询(表名1:a 表名2:b) 7*{9 2_M
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H2EKr#(
7、说明:在线视图查询(表名1:a ) c5KJ_Nfi
select * from (SELECT a,b,c FROM a) T where t.a > 1; o>3g<-ul
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 #HgXTC
select * from table1 where time between time1 and time2 oh>X/uj
select a,b,c, from table1 where a not between 数值1 and 数值2 FrPpRe %!
9、说明:in 的使用方法 ]g}Tqf/N%
select * from table1 where a [not] in ('值1','值2','值4','值6') ]t4 9Efw
10、说明:两张关联表,删除主表中已经在副表中没有的信息 m\h. sg&
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) D7'P^*4_B
11、说明:四表联查问题: (YOp
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 ..... IUK!b2!`
12、说明:日程安排提前五分钟提醒 +y}4^3Vx^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `#v(MK{9+V
13、说明:一条sql 语句搞定数据库分页 EUVB>%P
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 d-cK`pSB
14、说明:前10条记录 ="M7F0k
select top 10 * form table1 where 范围 gy%/zbZx
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.) \I3={ii0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) x+mfQcSD&
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 x{Gdr51%
(select a from tableA ) except (select a from tableB) except (select a from tableC) T3-8AUCK8?
17、说明:随机取出10条数据 ?AL;m.X-@
select top 10 * from tablename order by newid() Stq
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18、说明:随机选择记录 a.oZ}R7'Y
select newid() t&GjW6]W
19、说明:删除重复记录 ch^tq",1>
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) pONBF3H8
20、说明:列出数据库里所有的表名 #5Zf6w
select name from sysobjects where type='U' Jl,mYFEZ
21、说明:列出表里的所有的 WJB/X"J
select name from syscolumns where id=object_id('TableName') YLEk
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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。 `63?FzTy
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 SI/@Bbd=
显示结果: zmREzP#X
type vender pcs O@n1E'S/
电脑 A 1 /MHml0u
电脑 A 1 .H.#W1`
光盘 B 2 e~wuoE:M3
光盘 A 2 =*ZQGM 3w
手机 B 3 aa:97w~s0
手机 C 3 &7gL&AY8
23、说明:初始化表table1 L `7~~
TRUNCATE TABLE table1 _t9@
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24、说明:选择从10到15的记录 vCPiT2G
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc <Z8I#IPl
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三、技巧 n'dxa<F2|
1、1=1,1=2的使用,在SQL语句组合时用的较多 Pk94O
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 3I rmDT
如: 09_L^'`
if @strWhere !='' |'C{nTX
begin 6?"k&O
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Q t!X<.
end ev bqBb21b
else W?*]'0
begin %B;e7
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' [c{/0*
end } s0?RH
我们可以直接写成 v|VfSLZTb
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere xB%Felz
2、收缩数据库 "zT#*>U
--重建索引 ~6:<OdQ
DBCC REINDEX q.
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DBCC INDEXDEFRAG eyx;8v cM
--收缩数据和日志 B{:JD^V!
DBCC SHRINKDB h4j{44MT
DBCC SHRINKFILE r306`)kX
3、压缩数据库 qyfw$$X
dbcc shrinkdatabase(dbname) d[b(+sHp a
4、转移数据库给新用户以已存在用户权限 FwdRM)1)
exec sp_change_users_login 'update_one','newname','oldname' "IK QFt'
go {"cS:u
5、检查备份集 kt.y"^
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' %E!^SF?Y
6、修复数据库 tkN5|95
ALTER DATABASE [dvbbs] SET SINGLE_USER {}vB#!
GO r9x.c7=O
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK :3,aR\
GO 0a#2 Lo
ALTER DATABASE [dvbbs] SET MULTI_USER LD'eq\vO
GO {x$h K98
7、日志清除 Dm,*G`Js
SET NOCOUNT ON }d,iA FG
DECLARE @LogicalFileName sysname, Lyx \ s;
@MaxMinutes INT, FfDe&/,/
@NewSize INT *AO^oBeY
USE tablename -- 要操作的数据库名 sCX 8
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 r A/jNX@S
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Ha U6`IP
@NewSize = 1 -- 你想设定的日志文件的大小(M) l.DC20bs
-- Setup / initialize 7?@s.Sz|fV
DECLARE @OriginalSize int I?).D?o
SELECT @OriginalSize = size C
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FROM sysfiles Ab]`*h\U
WHERE name = @LogicalFileName wKjL}1.k
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {=(GY@yU/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + p8%/T>hK
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' W!$aK )]4u
FROM sysfiles tMWDKatb
WHERE name = @LogicalFileName h\ZnUn_J
CREATE TABLE DummyTrans 1:3I G=
(DummyColumn char (8000) not null) <f
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DECLARE @Counter INT, DP rFB y
@StartTime DATETIME, |<,!K;@
@TruncLog VARCHAR(255) MKad
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SELECT @StartTime = GETDATE(), @"`J~uK
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' %;SOe9
DBCC SHRINKFILE (@LogicalFileName, @NewSize) G~oGBq6Gz
EXEC (@TruncLog) MroJ!.9
-- Wrap the log if necessary. z|VQp,ra
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired "V|1w>s
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) p Rt=5WZ
AND (@OriginalSize * 8 /1024) > @NewSize DE GEr-
BEGIN -- Outer loop. ,S|v>i,@
SELECT @Counter = 0 |Rh%wJ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *vx!twu1o
BEGIN -- update we<m%pf
INSERT DummyTrans VALUES ('Fill Log') ZH9sf ~7
DELETE DummyTrans Q:.q*I!D<4
SELECT @Counter = @Counter + 1 (lDbArqy
END n[jyhBf\W
EXEC (@TruncLog) VA9"
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END k<mfBNvuo
SELECT 'Final Size of ' + db_name() + ' LOG is ' + N# Ru`;
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 80X #V
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' k79"xyXX
FROM sysfiles ogt<vng
WHERE name = @LogicalFileName R %QgOz3`
DROP TABLE DummyTrans P4{8pO]B
SET NOCOUNT OFF 6}aIb .j
8、说明:更改某个表 "Qf X&'09
exec sp_changeobjectowner 'tablename','dbo' `"N56
9、存储更改全部表 3JB?G>\!
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch D^(Nijl9U
@OldOwner as NVARCHAR(128), W'Wr8~{h
@NewOwner as NVARCHAR(128) 5*.JXxE;U
AS JLS|G?#0
DECLARE @Name as NVARCHAR(128) gr\UI!]F
DECLARE @Owner as NVARCHAR(128) .OLm{
DECLARE @OwnerName as NVARCHAR(128) kaSy 9Y{
DECLARE curObject CURSOR FOR %3L4&W_T
select 'Name' = name, %P!6cyQS
'Owner' = user_name(uid) C_SJ4Sh
from sysobjects KrcL*j&^
where user_name(uid)=@OldOwner >t-9yO1XQq
order by name )aW;w |#n
OPEN curObject wS*An4%G
FETCH NEXT FROM curObject INTO @Name, @Owner t'msgC6=>u
WHILE(@@FETCH_STATUS=0) WJefg
BEGIN h J*2q"
if @Owner=@OldOwner Lh0qB)>
begin 5PY,}1`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) FLT4:B7
exec sp_changeobjectowner @OwnerName, @NewOwner ;pK/t=$
end #KC& ct
-- select @name,@NewOwner,@OldOwner !f
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FETCH NEXT FROM curObject INTO @Name, @Owner -;/;d z;
END LvlVZjT
close curObject |@{4zoP_N
deallocate curObject =Q#}
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GO xgw[)!g^\
10、SQL SERVER中直接循环写入数据 {+CW_ce
declare @i int q; &\77i$
set @i=1 FerQA9K)x
while @i<30 QnsD,F; /
begin oPSucz&s
insert into test (userid) values(@i) RR,gC"cTi
set @i=@i+1 -+^E5
end zZrUS'8
小记存储过程中经常用到的本周,本月,本年函数 clE_a?
Dateadd(wk,datediff(wk,0,getdate()),-1) {Kn:>l$*7
Dateadd(wk,datediff(wk,0,getdate()),6) xign!=
Dateadd(mm,datediff(mm,0,getdate()),0) B@P +b*%
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) !q:[$g-@q
Dateadd(yy,datediff(yy,0,getdate()),0) FsZW,
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) cg16|
上面的SQL代码只是一个时间段 n<
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Dateadd(wk,datediff(wk,0,getdate()),-1) nVkPYeeT
Dateadd(wk,datediff(wk,0,getdate()),6) J2rw4L
就是表示本周时间段. 3v~804kWB
下面的SQL的条件部分,就是查询时间段在本周范围内的: JmHEYPt0
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~RlsgtX"
而在存储过程中 4/6?wX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) HYd&.*41rE
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6Fp}U