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。 8At<Wic
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一、基础 I:j3sy
1、说明:创建数据库 $.E6S<(h
CREATE DATABASE database-name -G |a*^
2、说明:删除数据库 9J-b6,
drop database dbname %VNlXHO.
3、说明:备份sql server r7mD{0s*
--- 创建 备份数据的 device ",qU,0
USE master :D:DnVZ-[@
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' f>$``.O
--- 开始 备份 Wd,a?31|
BACKUP DATABASE pubs TO testBack _.)eL3OF
4、说明:创建新表 )6X.Nfkb^k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 5g5'@vMN
根据已有的表创建新表: fz_nsVD
A:create table tab_new like tab_old (使用旧表创建新表) va)%et0!
B:create table tab_new as select col1,col2... from tab_old definition only Q;/a F`
5、说明:删除新表 L V{Q,DrP
drop table tabname >]D4Q<TY
6、说明:增加一个列 @* ust>7
Alter table tabname add column col type e /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。 GIwh@4;
7、说明:添加主键: Alter table tabname add primary key(col) 8(U{2B8>\%
说明:删除主键: Alter table tabname drop primary key(col) ;3'NMk
8、说明:创建索引:create [unique] index idxname on tabname(col....) MjL)IgT
删除索引:drop index idxname }?@5W,
注:索引是不可更改的,想更改必须删除重新建。 e&<yX
9、说明:创建视图:create view viewname as select statement 0ezYd S~o
删除视图:drop view viewname {Tp2H_EG
10、说明:几个简单的基本的sql语句 6=GZLpv
选择:select * from table1 where 范围 YUWn;#
插入:insert into table1(field1,field2) values(value1,value2) E+95WF|4k"
删除:delete from table1 where 范围 cQNs L
更新:update table1 set field1=value1 where 范围 ]2SI!Ai7
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! /B3R1kNf|
排序:select * from table1 order by field1,field2 [desc] #o`Ny4sq/
总数:select count as totalcount from table1 `|Z}2vo;j
求和:select sum(field1) as sumvalue from table1 kma?v B
平均:select avg(field1) as avgvalue from table1 coE&24,0
最大:select max(field1) as maxvalue from table1 .x83Ah`
最小:select min(field1) as minvalue from table1 Pt,ebL~
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11、说明:几个高级查询运算词 `6=-WEo
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A: UNION 运算符 )$%Z:
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。 $D1w5o-
B: EXCEPT 运算符 RBKOM$7
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。 :*514N
C: INTERSECT 运算符 ]jMKC8uz
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。 dtStTT
注:使用运算词的几个查询结果行必须是一致的。 S^I,Iz+`S'
12、说明:使用外连接 Dr<='Ux[5
A、left outer join: k`KGB
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。 <!d"E@%v@
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 "8f?h%t
B:right outer join: j V3)2C}
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。 h!@,8y[B
C:full outer join: JtKp(k&
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。 <i?a0
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二、提升 a
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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) z`Wt%tL(
法一:select * into b from a where 1<>1 (46 {r}_O
法二:select top 0 * into b from a c,EBF\r8*
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \/`?
insert into b(a, b, c) select d,e,f from b; UKd'+R]
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) 2.uA|~qH
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 1k8x%5p
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 9Ru;`
4、说明:子查询(表名1:a 表名2:b) imB# Eo4eY
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) 5v.DX`"
5、说明:显示文章、提交人和最后回复时间 <~U4*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b gwkb!#A
6、说明:外连接查询(表名1:a 表名2:b) yY{kG2b,
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^!{
7、说明:在线视图查询(表名1:a ) q}|U4MJm
select * from (SELECT a,b,c FROM a) T where t.a > 1; <z+:j!~
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
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select * from table1 where time between time1 and time2 BcWcdr+}9
select a,b,c, from table1 where a not between 数值1 and 数值2 `bI)<B
9、说明:in 的使用方法 `1` f*d
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select * from table1 where a [not] in ('值1','值2','值4','值6') <Cpp?DW_
10、说明:两张关联表,删除主表中已经在副表中没有的信息 YB))S!;Ok
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ^WYQ]@rh3
11、说明:四表联查问题: QWnndI_4p
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 ..... fN%jJ-[d
12、说明:日程安排提前五分钟提醒 >u+q1j.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ZM#=`k9
13、说明:一条sql 语句搞定数据库分页 `|O yRU"EK
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 3k$[r$+"
14、说明:前10条记录 j|fd-<ng
select top 10 * form table1 where 范围 le)DgIT>=
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.) 8ip7^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Fqq6^um
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 nt1CTWKM8^
(select a from tableA ) except (select a from tableB) except (select a from tableC) v9RW5
17、说明:随机取出10条数据 *V^ #ga#A
select top 10 * from tablename order by newid() is;XmF*5=
18、说明:随机选择记录 O>y'Nqz
select newid() 7Ey#u4Q
19、说明:删除重复记录 V ~MiO.B
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) rZ1Hf11C
20、说明:列出数据库里所有的表名 $P
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select name from sysobjects where type='U' $o?@0
21、说明:列出表里的所有的 eJ8]g49mD6
select name from syscolumns where id=object_id('TableName') 4'pS*v
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 :PYtR
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type .lG5=Th!
显示结果: PaB!,<A
type vender pcs 0'Z\O
电脑 A 1 SkNre$>t{
电脑 A 1 L6P1L)
光盘 B 2 1^J`1
光盘 A 2 SS|z*h
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手机 B 3 ;oOv/3
手机 C 3 v`[Eb27W.
23、说明:初始化表table1 yBed kj
TRUNCATE TABLE table1 we7c`1E
24、说明:选择从10到15的记录 .aOnGp
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,8G{]X)
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三、技巧 h&@R| N
1、1=1,1=2的使用,在SQL语句组合时用的较多 4 {GU6v)f
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 4\5uY
如: q6P
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if @strWhere !='' hIv@i\`
begin B@v\eF;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,3DXFV'uxb
end ?dZt[vAMn
else 9 t
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begin ;,'igdold
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' u'A#%}3
end 9a$56GnW1
我们可以直接写成 pY8q=Kl
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere KGHq rc
2、收缩数据库 `em9T oJV
--重建索引 XJ0{
DBCC REINDEX FE7)E.U
DBCC INDEXDEFRAG nQK|n^AU/
--收缩数据和日志 7EhN u@5-
DBCC SHRINKDB N)8HR9[!
DBCC SHRINKFILE 8G%yB}pa
3、压缩数据库 qAkx<u
dbcc shrinkdatabase(dbname) h #Z4pN8T3
4、转移数据库给新用户以已存在用户权限 N6QVt f.
exec sp_change_users_login 'update_one','newname','oldname' I 8
go u0`o A
5、检查备份集 N6oq90G
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "%2xR[NF
6、修复数据库 ~vdkFc(8B
ALTER DATABASE [dvbbs] SET SINGLE_USER ~q0*"\Ff
GO `Kl`VP=c
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK a@d=>CT$
GO s Wjy6;
ALTER DATABASE [dvbbs] SET MULTI_USER ({}( qm
GO ewsKH\#
7、日志清除 @MR?6 n*k
SET NOCOUNT ON !hxIlVd{
DECLARE @LogicalFileName sysname, v{x{=M]
@MaxMinutes INT, -]G(ms;}/Y
@NewSize INT (LAXM
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USE tablename -- 要操作的数据库名 2i#Sn' 1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 `:{B(+6
@MaxMinutes = 10, -- Limit on time allowed to wrap log. p^m5`{1]x
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0Sl]!PZR1
-- Setup / initialize -5G)?J/*
DECLARE @OriginalSize int 96Wp!]*
SELECT @OriginalSize = size uUR~&8ERX
FROM sysfiles M<?Q4a'Q
WHERE name = @LogicalFileName 2h30\/xkU
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ?`?T7w|3
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Jc4L5*Xn/
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' cX!Pz.C
FROM sysfiles or ;f&![w
WHERE name = @LogicalFileName ~rbIMF4T`]
CREATE TABLE DummyTrans rPzQ8<
(DummyColumn char (8000) not null) sPAg)6&M
DECLARE @Counter INT, 0Rxe~n1o
@StartTime DATETIME, +m\|e{G
@TruncLog VARCHAR(255) }peBR80tQ
SELECT @StartTime = GETDATE(), [BbutGvj
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1MkI0OZE
DBCC SHRINKFILE (@LogicalFileName, @NewSize) J<j&;:IRd
EXEC (@TruncLog) dpZ;l 9
-- Wrap the log if necessary. 9$K;Raz%
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired /Wk9-uH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )w~Fo,
AND (@OriginalSize * 8 /1024) > @NewSize Nf,Z;5e
BEGIN -- Outer loop. r4_eTrC,
SELECT @Counter = 0 <S"~vKD'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) De
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BEGIN -- update ["<nq`~
INSERT DummyTrans VALUES ('Fill Log') ~!6K]hB4
DELETE DummyTrans Tn-C>=tR~%
SELECT @Counter = @Counter + 1 DdV'c@rq+
END iyx>q!P
EXEC (@TruncLog) o(A|)c4k
END ;bu#8,
SELECT 'Final Size of ' + db_name() + ' LOG is ' + T0HuqJty
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + [jx0-3s:X
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' }b3/b
FROM sysfiles Hq &"+1F
WHERE name = @LogicalFileName \~rlgxd
DROP TABLE DummyTrans "+ "{+k5t
SET NOCOUNT OFF PnT)LqEF
8、说明:更改某个表 &FdWFt=X
exec sp_changeobjectowner 'tablename','dbo' gA#RM5x@
9、存储更改全部表
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |BMV.Zi
@OldOwner as NVARCHAR(128), >P KBo
@NewOwner as NVARCHAR(128) mumXUX
AS VUU]Pu &
DECLARE @Name as NVARCHAR(128) \79X{mcd
DECLARE @Owner as NVARCHAR(128) *2"6fX[
DECLARE @OwnerName as NVARCHAR(128) Die-@z|Y
DECLARE curObject CURSOR FOR $ls[|N:y0l
select 'Name' = name, C@y8.#l
'Owner' = user_name(uid) AS!6XT
from sysobjects qgt[ ~i*
where user_name(uid)=@OldOwner 3{Nbp
order by name _K9VMczj
OPEN curObject Lr;(xw\['
FETCH NEXT FROM curObject INTO @Name, @Owner |8_JY2
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WHILE(@@FETCH_STATUS=0) UAS@R`?cI
BEGIN Y+%sBqo@
if @Owner=@OldOwner ]6Ug>>x5
begin zkM"cb13q/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) F^aR+m
exec sp_changeobjectowner @OwnerName, @NewOwner 4] > ]-b
end
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-- select @name,@NewOwner,@OldOwner *TW=/+j
FETCH NEXT FROM curObject INTO @Name, @Owner 9D\4n
END Uh}seB#mJj
close curObject d87vl13
deallocate curObject PrQ?PvA<L
GO V2Q$g^X'
10、SQL SERVER中直接循环写入数据 [a[/_Sf{
declare @i int D:\ g,\Z
set @i=1 /h2b;"
while @i<30 %3;Fgk y
begin !4"sX+z9
insert into test (userid) values(@i) 1&=0Wg0ig
set @i=@i+1 ;.sl*q1A
end t,)N('m}=
小记存储过程中经常用到的本周,本月,本年函数 bZ_mYyBh
Dateadd(wk,datediff(wk,0,getdate()),-1) <<A`aU^fX
Dateadd(wk,datediff(wk,0,getdate()),6) jo+w>
Dateadd(mm,datediff(mm,0,getdate()),0) | aQ"3d
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) EUYCcL'G
Dateadd(yy,datediff(yy,0,getdate()),0) T70QJ=,
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 23(=Xp3;>
上面的SQL代码只是一个时间段 73A)lU.
Dateadd(wk,datediff(wk,0,getdate()),-1) iJFs0?*
Dateadd(wk,datediff(wk,0,getdate()),6) {Ee>n^1
就是表示本周时间段. B-.v0R`5
下面的SQL的条件部分,就是查询时间段在本周范围内的: X#a`K]!B
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) .Jb$l$5'w
而在存储过程中 b<I9 MR
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) UnDgu4#R`A
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) fJ*:{48