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。 5g-AB`6T
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一、基础 }%@q; "9`
1、说明:创建数据库 v{T%`WuPRf
CREATE DATABASE database-name !=Hu?F p
2、说明:删除数据库 /3!c
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drop database dbname k v>rv37u
3、说明:备份sql server CBVL/pxy
--- 创建 备份数据的 device ?q%&"
USE master 3Aqw)B'"_
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' T"tR*2HwSd
--- 开始 备份 ^_Ap?zn
BACKUP DATABASE pubs TO testBack &Se!AcvKF
4、说明:创建新表 j$5S_]2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) q9^6A90
根据已有的表创建新表: \?VNr2
A:create table tab_new like tab_old (使用旧表创建新表) [2 yxTK
B:create table tab_new as select col1,col2... from tab_old definition only lQ]8PR
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5、说明:删除新表 l0&Y",vy
drop table tabname QR#L1+Hn
6、说明:增加一个列 qTA,rr#p0
Alter table tabname add column col type ?c;T4@mB
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 q5UD!&W
7、说明:添加主键: Alter table tabname add primary key(col) z5|m`$gy
说明:删除主键: Alter table tabname drop primary key(col) xeGl}q|
8、说明:创建索引:create [unique] index idxname on tabname(col....) ]DO~7p[
删除索引:drop index idxname O
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注:索引是不可更改的,想更改必须删除重新建。 TB@0j
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9、说明:创建视图:create view viewname as select statement @}8~TbP
删除视图:drop view viewname K4[XP]\jr
10、说明:几个简单的基本的sql语句 l5*sCp*Z
选择:select * from table1 where 范围 \@KK X
插入:insert into table1(field1,field2) values(value1,value2) w9W0j
删除:delete from table1 where 范围 '20S oVp
更新:update table1 set field1=value1 where 范围 I/&uiC{l@
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! RY4b<i3
排序:select * from table1 order by field1,field2 [desc] nz}}m^-j
总数:select count as totalcount from table1 3%NbT
求和:select sum(field1) as sumvalue from table1 E;>BcPt5
平均:select avg(field1) as avgvalue from table1 jO9w7u6
最大:select max(field1) as maxvalue from table1 nB+UxU@
最小:select min(field1) as minvalue from table1 5J1q]^
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11、说明:几个高级查询运算词 }iZ>Gm'5
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A: UNION 运算符 ]%4rL
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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。 wBb J
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B: EXCEPT 运算符 Q
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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。 DsI{*#
C: INTERSECT 运算符 F\H^=P
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。 ,];4+&|8kW
注:使用运算词的几个查询结果行必须是一致的。 j&qJK,~
12、说明:使用外连接 U&\2\z3{
A、left outer join: 3!OO_
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。 UojHlTg#bT
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 +I9+L6>UR
B:right outer join: >.fN@8[
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。 :/1/i&a
C:full outer join: .0eHP
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。 49;2tl;F
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二、提升 Z#i5=,Bk
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) oV7A"8L^a
法一:select * into b from a where 1<>1 @6~OQN
法二:select top 0 * into b from a .).*6{_
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Q.d Hg7+D
insert into b(a, b, c) select d,e,f from b; | gou#zi
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) X` QfOs#\
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 3cp"UU}.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. IIW6;jS
4、说明:子查询(表名1:a 表名2:b) S(5aJ[7Zm
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) NyJ=^=F#
5、说明:显示文章、提交人和最后回复时间 #CM^f^*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b z
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6、说明:外连接查询(表名1:a 表名2:b) 4*<27
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1HBdIWhHv.
7、说明:在线视图查询(表名1:a ) ZUW~ZZ7Z:
select * from (SELECT a,b,c FROM a) T where t.a > 1; wkp|V{k
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 KLc<c1BZ
select * from table1 where time between time1 and time2 ,B,2t u2
select a,b,c, from table1 where a not between 数值1 and 数值2 ) $wX~k
9、说明:in 的使用方法 (:p&[HNuN
select * from table1 where a [not] in ('值1','值2','值4','值6') 7;_./c_@
10、说明:两张关联表,删除主表中已经在副表中没有的信息 8")1,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Q\>Kd
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11、说明:四表联查问题: fy|Ae
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 ..... ">? y\#OA
12、说明:日程安排提前五分钟提醒 ^PCshb##
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 E+ 65
13、说明:一条sql 语句搞定数据库分页 ?\7" A
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;VFMP
14、说明:前10条记录 8^H <dR
select top 10 * form table1 where 范围 0 w"&9+kV
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.) _~M*XJ] `
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 8: KlU(J
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 27;t,Oq}
(select a from tableA ) except (select a from tableB) except (select a from tableC) |<@X* #X5
17、说明:随机取出10条数据 s-Mzl?o
select top 10 * from tablename order by newid() C?Sy90f
18、说明:随机选择记录 !/w<F{cl
select newid() az (u=}
19、说明:删除重复记录 2<aBUGA
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) h5bQ
20、说明:列出数据库里所有的表名 T/%s7!E
select name from sysobjects where type='U' zl:
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21、说明:列出表里的所有的 &b 2Vt
select name from syscolumns where id=object_id('TableName') y@|gG&f
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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。 %#rH~E
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 ]F@XGJN
显示结果: su}>
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type vender pcs xQ
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电脑 A 1 1)aB']K%
电脑 A 1 r@3VN~
光盘 B 2 "28b&pm
光盘 A 2 Y5~_y?BX
手机 B 3 Q']
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手机 C 3 h Znq\p~
23、说明:初始化表table1 o;XzJ#P
TRUNCATE TABLE table1 -d+q +l>0
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc A0SEzX({[
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三、技巧 -{i;!XE$SR
1、1=1,1=2的使用,在SQL语句组合时用的较多 W9~vBU
"where 1=1" 是表示选择全部 "where 1=2"全部不选, _2V L%
如: I3QK~ V*j)
if @strWhere !='' \gRX:i#n
begin (gQ^jmZPG
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere dnVl;L8L3
end O_#Ag K<A
else XV+s 5C
begin 48CLnyYiF
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' YFD'&N,sx
end +A 6xY
我们可以直接写成 ve2GRTO^aC
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ,v$gWA!l
2、收缩数据库 g&y'#,'Q~,
--重建索引 dUOvv/,FZT
DBCC REINDEX `s (A&=g\
DBCC INDEXDEFRAG 0FfBD[E:
--收缩数据和日志 W$7db%qFx
DBCC SHRINKDB xQX,1NbH5
DBCC SHRINKFILE )A9K9pZj
3、压缩数据库 0 !yvcviw
dbcc shrinkdatabase(dbname) -o<L%Y<n2
4、转移数据库给新用户以已存在用户权限 M7&u_Cn?
exec sp_change_users_login 'update_one','newname','oldname' V3fd]rIP
go "ZDc$v:Qa
5、检查备份集 ^GG6%=g'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 0[@9f1Nk4
6、修复数据库 sw{,l"]<
ALTER DATABASE [dvbbs] SET SINGLE_USER cQ~}qE>I
GO {yQeLION
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ">]v'h(s
GO YB/A0 J
ALTER DATABASE [dvbbs] SET MULTI_USER pqO}=*v@
GO 5K13
7、日志清除 Bi9b"*LN
SET NOCOUNT ON jA R@?X
DECLARE @LogicalFileName sysname, 5;5;bBo~
@MaxMinutes INT, Hzs]\%"
@NewSize INT Qhb].V{utV
USE tablename -- 要操作的数据库名 )=TD}Xb
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 A2VN%dB
@MaxMinutes = 10, -- Limit on time allowed to wrap log. A6Ttx{]
@NewSize = 1 -- 你想设定的日志文件的大小(M) rMIr&T
-- Setup / initialize }R:e[lKj
DECLARE @OriginalSize int }18}VjC!
SELECT @OriginalSize = size R,CFU l7Q
FROM sysfiles [uP_F,Y/
WHERE name = @LogicalFileName Mw2?U>h1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + hM^#X,7
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Um9Gjd
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' az@{O4
FROM sysfiles Z- ;<R$
WHERE name = @LogicalFileName i8pM,Ppi~
CREATE TABLE DummyTrans vR<Y1<j
(DummyColumn char (8000) not null) BuMBnbT
DECLARE @Counter INT, @O9.~6
@StartTime DATETIME, tjc3;9
@TruncLog VARCHAR(255) y&Sl#IQ L
SELECT @StartTime = GETDATE(), _#xS1sD
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ,<n >g;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) v
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EXEC (@TruncLog) TB9{e!4
-- Wrap the log if necessary. #UL:#pY
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired q
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) rLO1Sv
AND (@OriginalSize * 8 /1024) > @NewSize WCT}OiLsL
BEGIN -- Outer loop. @s RRcP~
SELECT @Counter = 0 %cMX]U
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 4d3]L`
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BEGIN -- update E>f+ E8?
INSERT DummyTrans VALUES ('Fill Log') .w3.zZ0[
DELETE DummyTrans tZmo= 3+:
SELECT @Counter = @Counter + 1 q15t7-Z6
END |Fz/9+I
EXEC (@TruncLog) NXsDn&&O
END Br.$:g#
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $j*%}x~[
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + NfizX!w&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 4E]w4BG)
FROM sysfiles }}y$T(:l
WHERE name = @LogicalFileName ,> lOmyh
DROP TABLE DummyTrans QPf*!E
SET NOCOUNT OFF f tW-
8、说明:更改某个表 %LeG.~?
exec sp_changeobjectowner 'tablename','dbo' h^R EBPe
9、存储更改全部表 7YT%.ID
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch `s93P^%
@OldOwner as NVARCHAR(128), (c;F%m|
@NewOwner as NVARCHAR(128) !_CBf#0
AS !gA<9h
DECLARE @Name as NVARCHAR(128) 9}^nozR,I
DECLARE @Owner as NVARCHAR(128) FrBoE#
DECLARE @OwnerName as NVARCHAR(128) -N;$L~`iAt
DECLARE curObject CURSOR FOR .%;`:dtj
select 'Name' = name, o))z8n?b
'Owner' = user_name(uid)
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from sysobjects !h3$C\
where user_name(uid)=@OldOwner |O3wAxc3W
order by name +bpUb0.W
OPEN curObject .CGPG,\2
FETCH NEXT FROM curObject INTO @Name, @Owner 9IJBK
WHILE(@@FETCH_STATUS=0) h>\T1PM
BEGIN pw|f4c7AH
if @Owner=@OldOwner C+ar]Vi
begin JDPn
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 91%QO?hz
exec sp_changeobjectowner @OwnerName, @NewOwner |Iei!jm
end o2M+=O@
-- select @name,@NewOwner,@OldOwner Xc"l')1H
FETCH NEXT FROM curObject INTO @Name, @Owner q?}
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END &V/n!|q<H
close curObject FW* k O
deallocate curObject eC`} oEz
GO x!5b"
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10、SQL SERVER中直接循环写入数据 1;_tu
declare @i int 5cj]Y)I-~
set @i=1 A^lJlr:_`
while @i<30 g7\MFertR^
begin 38ac~1HjE
insert into test (userid) values(@i) "&h{+DHS
set @i=@i+1 Jr|"QRC
end Hq<Sg4nz
小记存储过程中经常用到的本周,本月,本年函数 aumWU{j=
Dateadd(wk,datediff(wk,0,getdate()),-1) pJ8;7u
Dateadd(wk,datediff(wk,0,getdate()),6) yM* CA,(c
Dateadd(mm,datediff(mm,0,getdate()),0) bloe|o!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) >]b>gc?3
Dateadd(yy,datediff(yy,0,getdate()),0) ])`+
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) {Hc [H-
上面的SQL代码只是一个时间段 B%y?+4;zA
Dateadd(wk,datediff(wk,0,getdate()),-1) >ZRCM
Dateadd(wk,datediff(wk,0,getdate()),6) HC1jN8WDY
就是表示本周时间段. `D
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下面的SQL的条件部分,就是查询时间段在本周范围内的: =AaTn::e/
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) O*qSc^ 9q
而在存储过程中 /hrVnki*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 'v|R' wi\
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 87&BF)]