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。 D|U bh ]
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一、基础 c^"4l
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1、说明:创建数据库 nv0D4 t
CREATE DATABASE database-name OE[7fDe'
2、说明:删除数据库 5X3JQ"z
drop database dbname 7]So=%q
3、说明:备份sql server LTBH/[q5
--- 创建 备份数据的 device X)(K|[
USE master V1P]pP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?$)a[UnqX
--- 开始 备份 <9H3d7%
BACKUP DATABASE pubs TO testBack Q7pCF,;
4、说明:创建新表 Otr=+i
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) :?EZ\WM7
根据已有的表创建新表: Lm!]m\LRZD
A:create table tab_new like tab_old (使用旧表创建新表) C!547(l[
B:create table tab_new as select col1,col2... from tab_old definition only 29 !QE>Q
5、说明:删除新表 &!;o[joG
drop table tabname c{`!$Z'k<
6、说明:增加一个列 ((AK7hb
Alter table tabname add column col type PC"=B[OlJ
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。 4D5Wse
7、说明:添加主键: Alter table tabname add primary key(col) D$KP>G
说明:删除主键: Alter table tabname drop primary key(col) | J'k9W"
8、说明:创建索引:create [unique] index idxname on tabname(col....) q%bFR[p<*
删除索引:drop index idxname (Of`VT3ZOA
注:索引是不可更改的,想更改必须删除重新建。 *eD[[HbKX
9、说明:创建视图:create view viewname as select statement oGZuYpa9
删除视图:drop view viewname >mCH!ey
10、说明:几个简单的基本的sql语句 '% _K"rb
选择:select * from table1 where 范围 6;~V@t
插入:insert into table1(field1,field2) values(value1,value2) B.?F^m@zS
删除:delete from table1 where 范围 vp&.
更新:update table1 set field1=value1 where 范围 5KbPpKpd
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 9pi{)PDJ
排序:select * from table1 order by field1,field2 [desc] Q7`)&^
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总数:select count as totalcount from table1 =MJRQV67
求和:select sum(field1) as sumvalue from table1 k5%)
平均:select avg(field1) as avgvalue from table1 s hq
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最大:select max(field1) as maxvalue from table1 ^^k9Acd~p
最小:select min(field1) as minvalue from table1 F@z%y'5 Z*
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11、说明:几个高级查询运算词 o=7e8l
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A: UNION 运算符 qoT&N,/
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 hX,RuI
B: EXCEPT 运算符 ( +S-
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 p4\sKF8-
C: INTERSECT 运算符 "tOm
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 D@5h$m5
注:使用运算词的几个查询结果行必须是一致的。 ZLVgK@l
12、说明:使用外连接 ]p4?nT@]
A、left outer join: >^W6'Q$P<
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 n<)A5UB5-
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c DIP%*b#l$\
B:right outer join: {&Rz>JK
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。 LH`$<p2''r
C:full outer join: U7fNA7#x"
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。 :%28*fl
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二、提升 <AJRU
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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) Bn.R,B0PL
法一:select * into b from a where 1<>1 vN]_/T+
法二:select top 0 * into b from a xe.f]a
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) g rI#' x
insert into b(a, b, c) select d,e,f from b; 7N5M=f.DS(
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) 2A*,9S|Y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 qUg/mdv&
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. "9X(.v0ze
4、说明:子查询(表名1:a 表名2:b) G^;]]Ji"
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) {w,^Z[<
5、说明:显示文章、提交人和最后回复时间 iB~dO @
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Zu~t )W
6、说明:外连接查询(表名1:a 表名2:b) :vS/Lzk
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c qauvwAMuX
7、说明:在线视图查询(表名1:a ) SEu:31k{o
select * from (SELECT a,b,c FROM a) T where t.a > 1; wsR\qq
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 9N2.:<so
select * from table1 where time between time1 and time2 0>;[EFL
select a,b,c, from table1 where a not between 数值1 and 数值2 ht+wi5b
9、说明:in 的使用方法 cdI"=B+C\
select * from table1 where a [not] in ('值1','值2','值4','值6') cF iTanu
10、说明:两张关联表,删除主表中已经在副表中没有的信息 YXF^4||j.c
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )\W}&9 >
11、说明:四表联查问题: VsL*&Fk
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 ..... ,Cy&tRjR B
12、说明:日程安排提前五分钟提醒 kA2)T,s74
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 J!Rqm!)q
13、说明:一条sql 语句搞定数据库分页 KZ=5"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 ,WoB)V.{(
14、说明:前10条记录 {)kL7>u]^V
select top 10 * form table1 where 范围 tqt~F2u
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.) ; d}n89DXj
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) DU5rB\!.~
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 |llmq'Q
(select a from tableA ) except (select a from tableB) except (select a from tableC) b+dmJ]c
17、说明:随机取出10条数据 ]r#NjP
select top 10 * from tablename order by newid() A~s6~
18、说明:随机选择记录 B>"-8#B[4
select newid() G 8tK"LC
19、说明:删除重复记录 ZxDh!_[s
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ,6A/| K-
20、说明:列出数据库里所有的表名 pUgas?e&
select name from sysobjects where type='U' i1HO>X:ea
21、说明:列出表里的所有的 27F:-C~.9
select name from syscolumns where id=object_id('TableName') !l9#a{#6l
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。 6Tq2WZ}<'
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 Pi%-bD/w
显示结果: V Kc`mE
type vender pcs O=u.J8S2
电脑 A 1 l`:-B'WM
电脑 A 1 An
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光盘 B 2 [H2su|rBI`
光盘 A 2 COH.`Tv{*
手机 B 3 #S|On[Q!
手机 C 3 h`tf!M D]
23、说明:初始化表table1 1bCS4fs^>
TRUNCATE TABLE table1 / pGx!
24、说明:选择从10到15的记录 i-sm 9K'ns
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc k6;pi=sYNW
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三、技巧 /sSif0I24
1、1=1,1=2的使用,在SQL语句组合时用的较多 C+C1(b;1
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0.wN&:I8t
如: :yOJL [x
if @strWhere !='' pQm-Hr78j
begin xfqu=z8X
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,` $2
end 2\Yv;J+;
else /\pUA!G)BD
begin 368H6 Jj
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' t.7_7`bin~
end EOGz;:b&
我们可以直接写成 [} %=&B
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere t\ 9Y)d
2、收缩数据库 L%.=SbmS
--重建索引 YgkQF0+
DBCC REINDEX _b[Pk;8}j;
DBCC INDEXDEFRAG ,0n=*o@W
--收缩数据和日志 w< |Lx#L}
DBCC SHRINKDB :*Z@UY
DBCC SHRINKFILE CyJZip
3、压缩数据库 #XAH`L\
dbcc shrinkdatabase(dbname) GS!1K(7
4、转移数据库给新用户以已存在用户权限 Q,\S3>1n
exec sp_change_users_login 'update_one','newname','oldname' .@Jos^rxgJ
go p;vrPS
5、检查备份集 .1""U
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' RgVg~?A@
6、修复数据库 A)f/ww)Q
ALTER DATABASE [dvbbs] SET SINGLE_USER m^a0JR}u9
GO M`@Es#s
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Now2ad&
GO 4"V6k4i5
ALTER DATABASE [dvbbs] SET MULTI_USER R!_1 *H$
GO V5d|Lpm
7、日志清除 z%/<|`
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SET NOCOUNT ON j(Tk6S
DECLARE @LogicalFileName sysname, $b"Ex>
@MaxMinutes INT, <``krPi
@NewSize INT 9h^TOZK)
USE tablename -- 要操作的数据库名 g);.".@"
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 d/Fy0=0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. )$E'2|Gm/
@NewSize = 1 -- 你想设定的日志文件的大小(M) xh!aB6m8R
-- Setup / initialize L(kW]
DECLARE @OriginalSize int wRE2rsXoU
SELECT @OriginalSize = size ;UWp0d%
FROM sysfiles E&|EokSyN
WHERE name = @LogicalFileName ?}U l(
SELECT 'Original Size of ' + db_name() + ' LOG is ' + eLop}*k
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + o%73M!-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' <+;
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FROM sysfiles VI^~I;M^
WHERE name = @LogicalFileName J y0TV jA
CREATE TABLE DummyTrans $
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(DummyColumn char (8000) not null) {Gr"oO`&"
DECLARE @Counter INT, |>=\
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@StartTime DATETIME, _K|?;j#x0k
@TruncLog VARCHAR(255) FGRG?d4?h
SELECT @StartTime = GETDATE(), 5~SBZYI
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' P,SI0$Z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Kr;F4G|Qt
EXEC (@TruncLog) aW$))J)0
-- Wrap the log if necessary. ~=pyA#VVJ"
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Bd*\|M
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Fk&A2C}$b
AND (@OriginalSize * 8 /1024) > @NewSize hUMFfc?
BEGIN -- Outer loop. [$%0[;jtS
SELECT @Counter = 0 DBzF\-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ZZ F\;
BEGIN -- update Y t0s
INSERT DummyTrans VALUES ('Fill Log') ;i;;{j@$i
DELETE DummyTrans |#(g8ua7
SELECT @Counter = @Counter + 1 ZUeA&&{
END y O?52YO
EXEC (@TruncLog) Zq"wq[GCN
END bR|1*<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + <fcw:Ae
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + xT3l>9i
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Dlu]4n[LB
FROM sysfiles 7#iT33(3
WHERE name = @LogicalFileName C)qP9uW
DROP TABLE DummyTrans ,DWC=:@X
SET NOCOUNT OFF |:d:uj/
8、说明:更改某个表 mi{ r7.e5I
exec sp_changeobjectowner 'tablename','dbo' JWs?az
9、存储更改全部表 1"HSM=p
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch sh8(+hg
@OldOwner as NVARCHAR(128), T1~,.(#
@NewOwner as NVARCHAR(128) q
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AS vpqMKyy
DECLARE @Name as NVARCHAR(128) f%TP>)jag!
DECLARE @Owner as NVARCHAR(128) 55|.MXzq
DECLARE @OwnerName as NVARCHAR(128) 7!E7XP6,~>
DECLARE curObject CURSOR FOR JQWW's}
select 'Name' = name, Rk52K*Dc
'Owner' = user_name(uid) d9uT*5f
from sysobjects 9w,u4q
where user_name(uid)=@OldOwner Ry iS
order by name ;Ajy54}7
OPEN curObject N&+DhKw
FETCH NEXT FROM curObject INTO @Name, @Owner 'QEQyJ0EB
WHILE(@@FETCH_STATUS=0) ^,;8ra*h
BEGIN h\$juIQa
if @Owner=@OldOwner r$.v"Wh)
begin
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) Q\<^ih51
exec sp_changeobjectowner @OwnerName, @NewOwner }x}JzA+2
end AehkEN&H/t
-- select @name,@NewOwner,@OldOwner @](\cT64i3
FETCH NEXT FROM curObject INTO @Name, @Owner r<L>~S>yb
END f Tc,"{
close curObject H)&pay
deallocate curObject Z8Il3b*)
GO V{G9E
10、SQL SERVER中直接循环写入数据 lEv<n6:_
declare @i int wC[Bh^]
set @i=1 o+Kh2;$)
while @i<30 ;P4tqY@
begin ym)`<[T
insert into test (userid) values(@i) )IP{yL8c
set @i=@i+1
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end 8q&*tpE
小记存储过程中经常用到的本周,本月,本年函数 &OSyU4r
Dateadd(wk,datediff(wk,0,getdate()),-1) j;b<oQH
Dateadd(wk,datediff(wk,0,getdate()),6) 1z[GY RSt
Dateadd(mm,datediff(mm,0,getdate()),0) H/ 6GD,0
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ~_Mz05J-\_
Dateadd(yy,datediff(yy,0,getdate()),0) B>&eciY
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Bswd20(w
上面的SQL代码只是一个时间段 J]|lCwF
Dateadd(wk,datediff(wk,0,getdate()),-1) }X`jhsqT
Dateadd(wk,datediff(wk,0,getdate()),6) \LS+.bp%
就是表示本周时间段. z~BrKdS
下面的SQL的条件部分,就是查询时间段在本周范围内的: |E)IJj
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) VX;tglu2
而在存储过程中 %Sdzr!I7*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) gZr/Dfy
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~|~j01#