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。 e'Njl?>3
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一、基础 2[zFKK
1、说明:创建数据库 :(ni/,~Q
CREATE DATABASE database-name TL'^@Y7X5
2、说明:删除数据库 g$+ $@~
drop database dbname |1!RvW:[!
3、说明:备份sql server [TRHcz n
--- 创建 备份数据的 device UaG
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USE master h'%iY6!fA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' _[M*o0[@W
--- 开始 备份 Qu]F<H*Y|
BACKUP DATABASE pubs TO testBack ;&=c@>!xP#
4、说明:创建新表 vuN!7*d+
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) iW oe
根据已有的表创建新表: |T3F:],`
A:create table tab_new like tab_old (使用旧表创建新表) hUR>NUK@8
B:create table tab_new as select col1,col2... from tab_old definition only xYSNop3_
5、说明:删除新表 II;
drop table tabname JlaT
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6、说明:增加一个列 H.-VfROi2
Alter table tabname add column col type cqXP} 5
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。 &RF*pU>
7、说明:添加主键: Alter table tabname add primary key(col) lfTDpKz3D
说明:删除主键: Alter table tabname drop primary key(col) [ H|ifi
8、说明:创建索引:create [unique] index idxname on tabname(col....) Oc A;+}>
删除索引:drop index idxname /fh[_!qN
注:索引是不可更改的,想更改必须删除重新建。 'wA4}f
9、说明:创建视图:create view viewname as select statement @
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删除视图:drop view viewname P~xP@?I%
10、说明:几个简单的基本的sql语句 _e4%<!1
选择:select * from table1 where 范围 `YL)[t? V
插入:insert into table1(field1,field2) values(value1,value2) *UxN~?N|
删除:delete from table1 where 范围 N./l\NtZ
更新:update table1 set field1=value1 where 范围 [cfKvROG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! JA!?vs
排序:select * from table1 order by field1,field2 [desc] ^&8FwV]
总数:select count as totalcount from table1 &-R(u}m-F
求和:select sum(field1) as sumvalue from table1 k
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平均:select avg(field1) as avgvalue from table1 *gGL5<%T:
最大:select max(field1) as maxvalue from table1 Fx!NRY_
最小:select min(field1) as minvalue from table1 <?h,;]U
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11、说明:几个高级查询运算词 D2N<a= #
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A: UNION 运算符 Tup2;\y
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。 _ -6IB>
B: EXCEPT 运算符 )y#~eYn
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。 )Up'W
C: INTERSECT 运算符 ))NiX^)8^
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。 sQl`0|VH
注:使用运算词的几个查询结果行必须是一致的。 z\g6E/ %%
12、说明:使用外连接 P70]Ju
A、left outer join: &\p=s.y?j
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。 09_5niaz[
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 *h9S\Pv>j
B:right outer join: "o{o9.w
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。 +CaA%u
C:full outer join: D-KQRe2@
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。 }.S4;#|hw
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二、提升 >Y>>lE!
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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) aMq|xHZ
法一:select * into b from a where 1<>1 `=QRC.b
法二:select top 0 * into b from a 6 {j}Z*)m
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) .$~zxd#zo
insert into b(a, b, c) select d,e,f from b; GYJ
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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) MpCK/eiC
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 _VM()n;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @o/126(k
4、说明:子查询(表名1:a 表名2:b) b,#lw_U"
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) #[LnDU8>9
5、说明:显示文章、提交人和最后回复时间 W3~xjS"h
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Lbwc2Q,.-
6、说明:外连接查询(表名1:a 表名2:b) d!z}!
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ?nc:B]=pTY
7、说明:在线视图查询(表名1:a ) 'jr[
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select * from (SELECT a,b,c FROM a) T where t.a > 1; WJA0 `<~
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 -qW[.B
select * from table1 where time between time1 and time2 y(92 Th$
select a,b,c, from table1 where a not between 数值1 and 数值2 lHI;fR
9、说明:in 的使用方法 xC}9W6
select * from table1 where a [not] in ('值1','值2','值4','值6') Ng 3r`S"_<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Rv=rO|&]
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) I|eYeJ3
11、说明:四表联查问题: tA{B~>
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 ..... BSd\Sg4
12、说明:日程安排提前五分钟提醒 }\Ri:&?
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _Gb O>'kE
13、说明:一条sql 语句搞定数据库分页 /UP1*L
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 T-)lnrs^
14、说明:前10条记录 0~( f<:
select top 10 * form table1 where 范围 lD41+x7
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.) aEvW<jHh
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) wRsh@I<
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 A.wuB
(select a from tableA ) except (select a from tableB) except (select a from tableC) ,B8u?{O
17、说明:随机取出10条数据 F!*tE&Se+
select top 10 * from tablename order by newid() 2T&n6t$p
18、说明:随机选择记录 sO$X5S C9
select newid() X Z4q{^o
19、说明:删除重复记录 2, R5mL$
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) lFT`
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20、说明:列出数据库里所有的表名 .sBwJZ
select name from sysobjects where type='U' d,+a}eTP'
21、说明:列出表里的所有的 =b_/_b$q
select name from syscolumns where id=object_id('TableName') *i,@d&J y]
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 a]4h5kJ';
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type <yg!D21Y
显示结果: 3z~d7J
type vender pcs T6^H%;G
电脑 A 1 K|V<e[X[V
电脑 A 1 ic=tVs
光盘 B 2 IDn$w^"
光盘 A 2 Sece#K2J|
手机 B 3 Bp9_\4
手机 C 3 D@?Tq,=
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23、说明:初始化表table1 =tQ^t4_
TRUNCATE TABLE table1 {\p&?
24、说明:选择从10到15的记录 -POsbb>
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Wz&[cj
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三、技巧 7 <<`9,
1、1=1,1=2的使用,在SQL语句组合时用的较多 -J]j=
"where 1=1" 是表示选择全部 "where 1=2"全部不选, k^Qd%;bdF
如: .g?Ppma
if @strWhere !='' a1
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begin )l6(ss!J
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere h\lyt(.s
end q5#6PYIq
else 7w5C
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begin Lc! t
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' H84Zg/ ^
end /H~]5JZ3-E
我们可以直接写成 !$pnE:K
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9(pF!}1%\
2、收缩数据库 c@|f'V4
--重建索引 (MzThGJK_
DBCC REINDEX ]47!Zo,
DBCC INDEXDEFRAG 9][A1+"
--收缩数据和日志 >41K>=K
DBCC SHRINKDB ?%ei+
DBCC SHRINKFILE ( q}{;
3、压缩数据库 J*D3=5&
dbcc shrinkdatabase(dbname) .1F41UyL
4、转移数据库给新用户以已存在用户权限 KMP[Ledr
exec sp_change_users_login 'update_one','newname','oldname' <tgfbY^nL
go t*wV<b
5、检查备份集 D!rD-e
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' (sp{.bU
6、修复数据库 FV\$M6
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ALTER DATABASE [dvbbs] SET SINGLE_USER ODCv^4}9
GO '#u=wyp
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK g:2\S=
GO TXbnK"XQ
ALTER DATABASE [dvbbs] SET MULTI_USER f{+X0Oj
GO f"Kl?IN8
7、日志清除 gr \vC
SET NOCOUNT ON 4XNkto
DECLARE @LogicalFileName sysname, QRHM#v S
@MaxMinutes INT, T854}RX[{
@NewSize INT 7VW/v4n
USE tablename -- 要操作的数据库名 q8H9au&/
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 UQnv#a>
@MaxMinutes = 10, -- Limit on time allowed to wrap log. DAQozhP8
@NewSize = 1 -- 你想设定的日志文件的大小(M) 3Gt@Fo=
-- Setup / initialize 1?{w~cF}
DECLARE @OriginalSize int x }i'2
SELECT @OriginalSize = size (d# W3
FROM sysfiles MrhJk
WHERE name = @LogicalFileName q(Zu;ecBN
SELECT 'Original Size of ' + db_name() + ' LOG is ' + kY#sQz}8
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + @ ]
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' @!::_E+F]
FROM sysfiles Z4{~
WHERE name = @LogicalFileName }0 =gP?.kE
CREATE TABLE DummyTrans r?}L^bK
(DummyColumn char (8000) not null) qhOV>j,d
DECLARE @Counter INT,
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@StartTime DATETIME, <^"0A
@TruncLog VARCHAR(255) "tz`@3,5dN
SELECT @StartTime = GETDATE(), M[6WcH0/T
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' |VmQ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) vnH[D)`@
EXEC (@TruncLog) z6'l" D'h
-- Wrap the log if necessary. :JCe,1!3@
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired &NK6U
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) K!;>/3Y2-
AND (@OriginalSize * 8 /1024) > @NewSize ~}ba2dU8
BEGIN -- Outer loop. ^i6`w_ /
SELECT @Counter = 0 :2-!bLo}&
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) L lVE5f?
BEGIN -- update P|;=dX#-
INSERT DummyTrans VALUES ('Fill Log') xcC^9BAj
DELETE DummyTrans _}Ec[c
SELECT @Counter = @Counter + 1 &u0on)E
END |1UJKJwX
EXEC (@TruncLog) yYvv!w+@Q
END $<d3g:
SELECT 'Final Size of ' + db_name() + ' LOG is ' + rNeSg=j
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + RaAvPIJa |
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N>',[4pJ|
FROM sysfiles >?ckBU9
WHERE name = @LogicalFileName ])mYE
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DROP TABLE DummyTrans ,dSP%?vV
SET NOCOUNT OFF z+X DN:
8、说明:更改某个表 5db9C}0
exec sp_changeobjectowner 'tablename','dbo' AHdh]pfH
9、存储更改全部表 TbR!u:J
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch H6i;MQ
@OldOwner as NVARCHAR(128), Q#sLIZ8=
@NewOwner as NVARCHAR(128) ,Cj` 0v#
AS 6F08$,%Y
DECLARE @Name as NVARCHAR(128) !z?;L_Lb
DECLARE @Owner as NVARCHAR(128) Y1L7s H 9
DECLARE @OwnerName as NVARCHAR(128) @ \JoICz
DECLARE curObject CURSOR FOR H]&^>Pvh
select 'Name' = name, rPF2IS(5
'Owner' = user_name(uid) h0Ilxa
from sysobjects [h~#5x
where user_name(uid)=@OldOwner v>p}f"$`
order by name {%XDr,myd
OPEN curObject F@jyTIS^
FETCH NEXT FROM curObject INTO @Name, @Owner 5Jm%*Wb
WHILE(@@FETCH_STATUS=0) P> ilRb
BEGIN o 9{~F`{p
if @Owner=@OldOwner y<*/\]t9L[
begin KcF#c_f
set @OwnerName = @OldOwner + '.' + rtrim(@Name) W,p?}KiO
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exec sp_changeobjectowner @OwnerName, @NewOwner ~+bS D<!b
end av4g/7=
-- select @name,@NewOwner,@OldOwner -aF\
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FETCH NEXT FROM curObject INTO @Name, @Owner b%D}mxbS
END /\|Behif
close curObject Nm, 9xq
deallocate curObject z.]
GO ul[+vpH9
10、SQL SERVER中直接循环写入数据 tU, >EbwO
declare @i int TaE&8;H#N
set @i=1 +N>&b%
while @i<30 j;_
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begin &/tGT3)
insert into test (userid) values(@i) o+
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set @i=@i+1 R,KoymXP
end P xiJ R[a
小记存储过程中经常用到的本周,本月,本年函数 j3)fmlA
Dateadd(wk,datediff(wk,0,getdate()),-1) J:JkX>n%k=
Dateadd(wk,datediff(wk,0,getdate()),6) 8@-
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Dateadd(mm,datediff(mm,0,getdate()),0) vILq5iR
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) fKjUEMRK
Dateadd(yy,datediff(yy,0,getdate()),0) CJ#1j>
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :;u?TFCRx
上面的SQL代码只是一个时间段 !;~6nYY
Dateadd(wk,datediff(wk,0,getdate()),-1) @"gWvs
Dateadd(wk,datediff(wk,0,getdate()),6) 1*ui|fuK
就是表示本周时间段. lgaE2`0 [3
下面的SQL的条件部分,就是查询时间段在本周范围内的: Fi_JF;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) H:>i:\J/M9
而在存储过程中 95^A !
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ibIo1i//[
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =TG[isC/F9