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。 O_1[KiZ
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一、基础 :CE4<
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1、说明:创建数据库 KL=<s#
CREATE DATABASE database-name Cty#|6k
2、说明:删除数据库 m4@NW*G{
drop database dbname -:ucp2
3、说明:备份sql server BJUj#s0$
--- 创建 备份数据的 device $!>.h*np
USE master K{ar)_V/
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 0i_:J
--- 开始 备份 +v;z^+
BACKUP DATABASE pubs TO testBack T3P9
4、说明:创建新表 KCTX2eNN&h
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) %nY\"
根据已有的表创建新表: Pt"H_SW~k
A:create table tab_new like tab_old (使用旧表创建新表) 7m-%
B:create table tab_new as select col1,col2... from tab_old definition only _aPAn|.
5、说明:删除新表 pc*)^S
drop table tabname WChP,hw
6、说明:增加一个列 hNN[dj R
Alter table tabname add column col type QnVr)4"
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 l@B9}Icq
7、说明:添加主键: Alter table tabname add primary key(col) ac l<dY6
说明:删除主键: Alter table tabname drop primary key(col) DD$>3`
8、说明:创建索引:create [unique] index idxname on tabname(col....) GV Xdyi
删除索引:drop index idxname AChz}N$C
注:索引是不可更改的,想更改必须删除重新建。 |2q3spd
9、说明:创建视图:create view viewname as select statement AVpg
删除视图:drop view viewname ]Orx%8QS!
10、说明:几个简单的基本的sql语句 g&FTX>wX
选择:select * from table1 where 范围 g.Xk6"kO
插入:insert into table1(field1,field2) values(value1,value2) v~Q'm1!O4\
删除:delete from table1 where 范围 4MS<t FH)
更新:update table1 set field1=value1 where 范围 C")genMH
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Kb?{^\FiU
排序:select * from table1 order by field1,field2 [desc] ~'_cBJ
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总数:select count as totalcount from table1 ~+dps i
求和:select sum(field1) as sumvalue from table1 GjhTF|
平均:select avg(field1) as avgvalue from table1 !CYC7HeF
最大:select max(field1) as maxvalue from table1 <PpvVDy3
最小:select min(field1) as minvalue from table1 [Iks8ZWr_
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11、说明:几个高级查询运算词 Q>%n&;:
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A: UNION 运算符 ~(d
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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。 F]3Y,{/V
B: EXCEPT 运算符 s7Agr!>f
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。
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C: INTERSECT 运算符 nzflUR{`-
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。 zi-_ l
注:使用运算词的几个查询结果行必须是一致的。 ;>?h/tS6
12、说明:使用外连接 Ki;SONSV~|
A、left outer join: 7s(tAbPdB
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。 92DM1~
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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 6CBk=)qH
B:right outer join: I$7eiW @
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。 +&
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C:full outer join: -@#w)
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。 {zFME41>g
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二、提升 E^i]eK*"
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用)
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法一:select * into b from a where 1<>1 aas.-NT
法二:select top 0 * into b from a v=N?(6T
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 3xChik{
insert into b(a, b, c) select d,e,f from b; =j,WQ66r3
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) Nwi|>'\C
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 yn62NyK
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. &P?2H66s
4、说明:子查询(表名1:a 表名2:b) o:@Q1+p
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) Urr%SIakvM
5、说明:显示文章、提交人和最后回复时间 L|'^P3#7`
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b >pU9}2fpT
6、说明:外连接查询(表名1:a 表名2:b) }g}Eh>U
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !a@)6or
7、说明:在线视图查询(表名1:a ) ,S-h~x
select * from (SELECT a,b,c FROM a) T where t.a > 1; w"^h<]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 9"P|Csj
select * from table1 where time between time1 and time2 dVQ[@u1,
select a,b,c, from table1 where a not between 数值1 and 数值2 79h~w{IT@
9、说明:in 的使用方法 e,U:H~+]
select * from table1 where a [not] in ('值1','值2','值4','值6') ShB]U5b:k
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .;?!I_`
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) !
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11、说明:四表联查问题: z]G|)16
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 ..... g":[rXvId
12、说明:日程安排提前五分钟提醒 R+M&\ 5
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 W:d
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13、说明:一条sql 语句搞定数据库分页 A'|!O:s
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 BN_h3|)
14、说明:前10条记录 |9I)YD
select top 10 * form table1 where 范围 ix3LB!k<
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.) Zl9@E;|=
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )%7P?^>
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 /'/I^ab
(select a from tableA ) except (select a from tableB) except (select a from tableC)
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17、说明:随机取出10条数据 g$nS6w|5H
select top 10 * from tablename order by newid() x;/LOa{LR
18、说明:随机选择记录 B
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select newid() @]@|H?
19、说明:删除重复记录 A l U^,X
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) iod%YjZu
20、说明:列出数据库里所有的表名 ||$&o!;/L
select name from sysobjects where type='U' fvkcJwkc
21、说明:列出表里的所有的 Mbi]EZ
select name from syscolumns where id=object_id('TableName') P$)g=/td1
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。 =S&`~+
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 C?<pD+]b_
显示结果: Q.mJ7T~T
type vender pcs /at7H!
电脑 A 1 CXlbtpK2k
电脑 A 1 qkb'@f=
光盘 B 2 EApKN@<"
光盘 A 2 Z>rY9VvWD
手机 B 3 eVXXn)>
手机 C 3 C 0w+
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23、说明:初始化表table1 TQa}Ps
TRUNCATE TABLE table1 r"7n2
24、说明:选择从10到15的记录 m#7(<#
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >Fel) a
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三、技巧 :KLXrr
1、1=1,1=2的使用,在SQL语句组合时用的较多 xA] L0h]
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ]?Ef0?44
如: + ?1GscJ
if @strWhere !='' 8Lo#{`
begin j|eA*UE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere EYAaK^ &
end \(o"/*
else oaoTd$/5
begin /R)wM#&
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Tg\bpLk0=
end YDt+1Kw}D
我们可以直接写成 @AsJnf$y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere +a1x;
2、收缩数据库 Cm}2 >eH
--重建索引 LFp "Waiv
DBCC REINDEX o5 L ^
DBCC INDEXDEFRAG F@w; .e!
--收缩数据和日志 MY&Jdmga
DBCC SHRINKDB D Ez,u^
DBCC SHRINKFILE 25^?|9o 7
3、压缩数据库 <wH+\
dbcc shrinkdatabase(dbname) p9(y b
4、转移数据库给新用户以已存在用户权限 D &@]
exec sp_change_users_login 'update_one','newname','oldname' \/A.j|by,>
go g)D_!iz
5、检查备份集 Fnw:alWr
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' dAo;y.3
6、修复数据库 Rj8%% G-pt
ALTER DATABASE [dvbbs] SET SINGLE_USER k+3qX'fd
GO 8%?y)K^
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK rqdwQ
GO !rvEo =^
ALTER DATABASE [dvbbs] SET MULTI_USER ~wc:/UM|
GO v9*m0|T0M
7、日志清除 JxAQ,oOO
SET NOCOUNT ON e[S`Dm"i)'
DECLARE @LogicalFileName sysname, I2cz:U7
@MaxMinutes INT, 7s9h:/Lu
@NewSize INT wj|Zn+{"nF
USE tablename -- 要操作的数据库名 Vz{+3vfra6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ]Bw0Qq F#
@MaxMinutes = 10, -- Limit on time allowed to wrap log. sDY~jP[Oa
@NewSize = 1 -- 你想设定的日志文件的大小(M) IK~&`n](>
-- Setup / initialize [6/QUD8
DECLARE @OriginalSize int 0XHQ5+"8
SELECT @OriginalSize = size M6Fo.eeK3
FROM sysfiles Q?{%c[s
WHERE name = @LogicalFileName U84W(X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + P]E-Wp'p
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + j0jl$^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' q'2vE;z Kb
FROM sysfiles \l%xuT
WHERE name = @LogicalFileName jG5HW*>k0
CREATE TABLE DummyTrans nB[-KS
(DummyColumn char (8000) not null) ~(5r+Z}*`
DECLARE @Counter INT, k9|5TLXq?
@StartTime DATETIME, ]I*c:(qwu
@TruncLog VARCHAR(255) `?Rq44=
SELECT @StartTime = GETDATE(), U$rMZk
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' H=t"qEp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 2iAC_"n
EXEC (@TruncLog) p{FI_6db
-- Wrap the log if necessary. Bf_$BCyGW
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired '`];=QY9pg
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) |@qw
AND (@OriginalSize * 8 /1024) > @NewSize 3r\8v`^>
BEGIN -- Outer loop. [,%=\%5
SELECT @Counter = 0 l6viP}R
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 2hE(h
BEGIN -- update C*9X;+S0J
INSERT DummyTrans VALUES ('Fill Log') 1I+9?fa
DELETE DummyTrans FhE{khc#
SELECT @Counter = @Counter + 1 gr=h!'m
END %x)bZ=An
EXEC (@TruncLog) M[uWX=
END s?SspuV
SELECT 'Final Size of ' + db_name() + ' LOG is ' + x 3@-E
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ao(T81
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 1GY2aZ@
FROM sysfiles %|Ps|iV
WHERE name = @LogicalFileName [U\?+@E*
DROP TABLE DummyTrans a"8[,A3
SET NOCOUNT OFF sdu?#O+c1
8、说明:更改某个表 }`"`VLh
exec sp_changeobjectowner 'tablename','dbo' W&z jb>0b0
9、存储更改全部表 kc,"w\ ai
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch BFLef3~.0
@OldOwner as NVARCHAR(128), 5J5si<v25
@NewOwner as NVARCHAR(128) /
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AS w =^.ICyb@
DECLARE @Name as NVARCHAR(128) :Pud%}'
DECLARE @Owner as NVARCHAR(128) c:R?da
DECLARE @OwnerName as NVARCHAR(128) ?J[3_!"t
DECLARE curObject CURSOR FOR "fFSZ@,r
select 'Name' = name, _|HhT^\P
'Owner' = user_name(uid) 1uF$$E6[
from sysobjects QYJ
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where user_name(uid)=@OldOwner 2*Z2uV^
order by name 8*ZsR)!
OPEN curObject rIb+c=|F
FETCH NEXT FROM curObject INTO @Name, @Owner 49$P
WHILE(@@FETCH_STATUS=0) <LX\s*M)
BEGIN J[ds.~ $
if @Owner=@OldOwner gN&i&%*!
begin pO]gf$
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5dBftTv?
exec sp_changeobjectowner @OwnerName, @NewOwner %36x'Dn?
end *zfgO pK
-- select @name,@NewOwner,@OldOwner :yay:3qv
FETCH NEXT FROM curObject INTO @Name, @Owner h8rW"8Th
END 6&3,fSP
close curObject !,4ag1
deallocate curObject V0ze7tSG[f
GO 8^mE<
10、SQL SERVER中直接循环写入数据 |rm elQ-
declare @i int kmB!NxF>)F
set @i=1 !^J;S%MB:K
while @i<30 !iXRt" )
begin \1EuHQ?
insert into test (userid) values(@i) -(VJ,)8t2
set @i=@i+1 ul{x|R
end mh
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小记存储过程中经常用到的本周,本月,本年函数 Ts iJK
Dateadd(wk,datediff(wk,0,getdate()),-1) |diI(2w
Dateadd(wk,datediff(wk,0,getdate()),6) U'jt'(
Dateadd(mm,datediff(mm,0,getdate()),0) ~^t@TMk$
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) z^Q'GBoBA
Dateadd(yy,datediff(yy,0,getdate()),0) XxqGsGx4
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <}a?<):S
上面的SQL代码只是一个时间段 +X?ErQm
Dateadd(wk,datediff(wk,0,getdate()),-1) ~ELY$G.xl
Dateadd(wk,datediff(wk,0,getdate()),6) =w2 4(S
就是表示本周时间段. PK*Wu<<
下面的SQL的条件部分,就是查询时间段在本周范围内的: K+g[E<x\=
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) X-pbSq~5
而在存储过程中 [g}Cve#i
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) _0H oJ
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0zt]DCdY