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。 '`'GK&)
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一、基础 (}. @b|s
1、说明:创建数据库 Y*_)h\f
CREATE DATABASE database-name V"cKJ;s
2、说明:删除数据库 f7Ul(D:j\
drop database dbname q&C""!h^
3、说明:备份sql server :Xc@3gF
--- 创建 备份数据的 device O1')nYF7
USE master tx?dIy;
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -}K<ni6
--- 开始 备份 9&<x17'
BACKUP DATABASE pubs TO testBack B|o2K}%f
4、说明:创建新表 BL@:!t
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ?UM*Xah
根据已有的表创建新表: keRE==(D
A:create table tab_new like tab_old (使用旧表创建新表) Em[DHfu1Q
B:create table tab_new as select col1,col2... from tab_old definition only 04r$>#E
5、说明:删除新表 L(GjZAP
drop table tabname j*xV!DqC
6、说明:增加一个列 c8Z wr]DF
Alter table tabname add column col type vb9OonE2
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 E2)h?cs
7、说明:添加主键: Alter table tabname add primary key(col) hsu{ey p
说明:删除主键: Alter table tabname drop primary key(col) fnx-s{c?
8、说明:创建索引:create [unique] index idxname on tabname(col....) \.M*lqI
删除索引:drop index idxname TLehdZ>^
注:索引是不可更改的,想更改必须删除重新建。 @cU&n6C@
9、说明:创建视图:create view viewname as select statement 8enEA^
删除视图:drop view viewname 1+?N#Fh
10、说明:几个简单的基本的sql语句 hY`\&@
选择:select * from table1 where 范围 ybp -$e
插入:insert into table1(field1,field2) values(value1,value2) 3Hf0MAt
删除:delete from table1 where 范围 .s$z/Jv
更新:update table1 set field1=value1 where 范围 ;c$ J=h]
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! .k,YlFvj
排序:select * from table1 order by field1,field2 [desc] O|_h_I-2
总数:select count as totalcount from table1 `~eUee3b.~
求和:select sum(field1) as sumvalue from table1 GfC5z n>
平均:select avg(field1) as avgvalue from table1 !?Wp+e6
最大:select max(field1) as maxvalue from table1 }@.|?2b +
最小:select min(field1) as minvalue from table1 FLEo*9u>b
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11、说明:几个高级查询运算词 e}1uz3Rh
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A: UNION 运算符 n]he-NHP
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。 +^;JS3p@\
B: EXCEPT 运算符 ,AT[@
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。 (p%>j0<
C: INTERSECT 运算符 \TU3rk&X
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。 y(K"
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注:使用运算词的几个查询结果行必须是一致的。 Z0l+1iMx
12、说明:使用外连接 K_&4D'
A、left outer join: Mw9 \EhA
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。 [`
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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 #:SNHM^><
B:right outer join: EYA,hc
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。 =*Bl|;>6
C:full outer join: /*0K92NB
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。 )=Jk@yj8x
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二、提升 Dd`Mv$*d8
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) e1P"[|9>R
法一:select * into b from a where 1<>1 7g3>jh
法二:select top 0 * into b from a %.Q
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) W^"AU;^V56
insert into b(a, b, c) select d,e,f from b; JchSMc.9
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) tJN<PCG6"
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ;| 1$Q!4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <tioJG{OT
4、说明:子查询(表名1:a 表名2:b) i~r l o^
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) z;y:9l
5、说明:显示文章、提交人和最后回复时间 3do)Vg4
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b |fo0
6、说明:外连接查询(表名1:a 表名2:b) }NB}"%2
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @V!r"Bkg.
7、说明:在线视图查询(表名1:a ) H=
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select * from (SELECT a,b,c FROM a) T where t.a > 1; 5 (A5Y-B
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 <I;2{*QI2
select * from table1 where time between time1 and time2 ZRYEqSm
select a,b,c, from table1 where a not between 数值1 and 数值2 !F?XLekTi
9、说明:in 的使用方法 }\C-}
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select * from table1 where a [not] in ('值1','值2','值4','值6') %iw3oh&Fkm
10、说明:两张关联表,删除主表中已经在副表中没有的信息 63A}TBC
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) }u1O#L}F5
11、说明:四表联查问题: @e{^`\ l=<
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 ..... ^aW
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12、说明:日程安排提前五分钟提醒 D+>1]ij
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0iJue&
13、说明:一条sql 语句搞定数据库分页 yq$,,#XDD=
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 I|Gp$uq _
14、说明:前10条记录 Rn@#d}
select top 10 * form table1 where 范围 ^b
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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.) /7
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) }1r m
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 YID4w7|
(select a from tableA ) except (select a from tableB) except (select a from tableC) yDGVrc'
17、说明:随机取出10条数据 k?7 X3/O
select top 10 * from tablename order by newid() )rixMl &[
18、说明:随机选择记录 C"{k7yT
select newid() H$6`{lx,
19、说明:删除重复记录 KZeQ47|
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ]~Z6;
20、说明:列出数据库里所有的表名 0#MqD[U(
select name from sysobjects where type='U' h\'n**f_x
21、说明:列出表里的所有的 %'T #pz
select name from syscolumns where id=object_id('TableName') N
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ,GgAsj: K
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type L31|\x]
显示结果: D$x_o!JT
type vender pcs dh $bfAb
电脑 A 1 h?pkE
电脑 A 1 3g6j?yYqb
光盘 B 2 Ox@P6|m
光盘 A 2 ^I+)o1%F
手机 B 3 >
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手机 C 3 +}a ]GTBgA
23、说明:初始化表table1 e$pMsw'MJ
TRUNCATE TABLE table1 BX yo
24、说明:选择从10到15的记录 C$5[X7'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc %!1Q P[}K
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三、技巧 CJ++?hB]X
1、1=1,1=2的使用,在SQL语句组合时用的较多 [VWUqlNt>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, M4W5f#C5Ee
如: Rx+p.
if @strWhere !='' c}0@2Vf
begin tzh1s
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere nb>7UN.9
end ;{[.Zu
else y.Z?LCd<
begin <Z/x,-^*<
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' r4#o+qE
end p"U,G
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我们可以直接写成 .e3+s*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S1?-I_t+]
2、收缩数据库 s@7H1)U
--重建索引 )sT> i
DBCC REINDEX /7YF mI/0
DBCC INDEXDEFRAG ]H1I,`=@
--收缩数据和日志 9cj9SB4
DBCC SHRINKDB LA)[ip4
DBCC SHRINKFILE |u ;v27
3、压缩数据库 a.zpp'cEb
dbcc shrinkdatabase(dbname) j.@\3'
4、转移数据库给新用户以已存在用户权限 ,#kIr
exec sp_change_users_login 'update_one','newname','oldname' z+>}RT]
go tmtT(
5、检查备份集 ::/j$bL
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' vZBc!AW
6、修复数据库 [r[=W!
ALTER DATABASE [dvbbs] SET SINGLE_USER -bU oCF0
GO ;I!MLI
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK jXMyPNTK
GO >MvDVPi~+
ALTER DATABASE [dvbbs] SET MULTI_USER v 7x:dcV
GO y?q*WUh
7、日志清除 $81*^
SET NOCOUNT ON }:~x7|~s:
DECLARE @LogicalFileName sysname, ze]h..,]K
@MaxMinutes INT, yiA<,!;4P
@NewSize INT 5O6hxcMjT
USE tablename -- 要操作的数据库名 r#B+(X7LM
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 "^]cQ"A
@MaxMinutes = 10, -- Limit on time allowed to wrap log. -Zz$~$
@NewSize = 1 -- 你想设定的日志文件的大小(M) w4d--[Q
-- Setup / initialize .>IhN 5
DECLARE @OriginalSize int s]JF0584
SELECT @OriginalSize = size _> *jH'
FROM sysfiles L;f!.FX#
WHERE name = @LogicalFileName 5kz)5,KjM
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ,c)uX#1
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2]ape !(
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' >cCR2j,r
FROM sysfiles VH1d$
WHERE name = @LogicalFileName d8x \
CREATE TABLE DummyTrans
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(DummyColumn char (8000) not null) G@Z?&"
DECLARE @Counter INT, I=NZokfS
@StartTime DATETIME, h|"9LU4a
@TruncLog VARCHAR(255) Bb"Bg\le,^
SELECT @StartTime = GETDATE(), jav#f{'
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' =Yt
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) #*(td<Cp
EXEC (@TruncLog) _Iv6pNd/
-- Wrap the log if necessary. %$Aqle[
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8UVmv=T
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) fOMW"myQ
AND (@OriginalSize * 8 /1024) > @NewSize PuZf/um
BEGIN -- Outer loop. 6<ZkJ:=
SELECT @Counter = 0 %&Q$dzgb_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) aWY
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BEGIN -- update _&b4aW9<
INSERT DummyTrans VALUES ('Fill Log') 4sT88lG4n
DELETE DummyTrans Z7?~S2{c
SELECT @Counter = @Counter + 1 '`uwJ&@
END y)@[Sl>
EXEC (@TruncLog) \0f{S40
END W0]gLw9*
SELECT 'Final Size of ' + db_name() + ' LOG is ' + i0$kit
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + xsMBC
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 9*1,!%]
FROM sysfiles /Dj=iBO
WHERE name = @LogicalFileName 8!Ww J
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DROP TABLE DummyTrans 7F{3*`/6
SET NOCOUNT OFF '5|h)Q5
8、说明:更改某个表 `p;I}
exec sp_changeobjectowner 'tablename','dbo' -B$2\ZE
9、存储更改全部表 jyZWVL:_
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch eXf22;Lz
@OldOwner as NVARCHAR(128), b8LLr;oQw
@NewOwner as NVARCHAR(128) >\Ww;1yV
AS 5w@4:$=I
DECLARE @Name as NVARCHAR(128) ] A+?EE2/
DECLARE @Owner as NVARCHAR(128) d >t<_}
DECLARE @OwnerName as NVARCHAR(128) I]EbodAyZ,
DECLARE curObject CURSOR FOR AQ[GO6$,%H
select 'Name' = name, G8Y<1%`<
'Owner' = user_name(uid) % V8U(z
from sysobjects uD@#
where user_name(uid)=@OldOwner lH6OcD:kj
order by name n@,G8=J?
OPEN curObject _c_[C*T]
FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) Gvr@|{k
BEGIN EpX&R,Rxk
if @Owner=@OldOwner P IwFF}<(
begin 3skC$mpJHw
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,~]tg77
exec sp_changeobjectowner @OwnerName, @NewOwner <
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end 4s*ZS}]
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-- select @name,@NewOwner,@OldOwner u;/ Vyu
FETCH NEXT FROM curObject INTO @Name, @Owner x}"uZ$g
END
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close curObject xe`
</
deallocate curObject @6]sNm
GO 7M<'/s
10、SQL SERVER中直接循环写入数据 F6{bjv2A
declare @i int <yH4HY
set @i=1 +yD`3`
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while @i<30 <,e+
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begin "\o+v|;
insert into test (userid) values(@i) )j0TeE1R
set @i=@i+1 In<n&ib
end 7OJ'){R$
小记存储过程中经常用到的本周,本月,本年函数 Gf<'WQ[
Dateadd(wk,datediff(wk,0,getdate()),-1) ikvWh<=>H
Dateadd(wk,datediff(wk,0,getdate()),6) qtQ6cqLd
Dateadd(mm,datediff(mm,0,getdate()),0) l)&X$3? tz
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ''\Ov
Dateadd(yy,datediff(yy,0,getdate()),0) +N:o-9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) zM(vr"U
上面的SQL代码只是一个时间段 L'0B$6
Dateadd(wk,datediff(wk,0,getdate()),-1) OZ~5*v
Dateadd(wk,datediff(wk,0,getdate()),6) )6D,d5<
就是表示本周时间段. :i .{
下面的SQL的条件部分,就是查询时间段在本周范围内的: "C{}Z
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 'DL`Ee\
而在存储过程中 t? yz
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ov_j4j>6P
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) [8=vv7wS