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。 DwK$c^2q{.
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一、基础 +.rE|)BPy
1、说明:创建数据库 m?1r@!/y
CREATE DATABASE database-name ay`R jT
2、说明:删除数据库 ;>fM?ae5
drop database dbname ]3Ibl^J
3、说明:备份sql server /n:Q>8^n'W
--- 创建 备份数据的 device b_u;
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USE master %sPq*w.
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' U-$nwji
--- 开始 备份 Okd. ~
BACKUP DATABASE pubs TO testBack %h;1}SFl0
4、说明:创建新表 dB QCr{7
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ccx0aC3@I
根据已有的表创建新表: DMSC(Sz
A:create table tab_new like tab_old (使用旧表创建新表) >z%WW&Z'
B:create table tab_new as select col1,col2... from tab_old definition only YY$Z-u(
5、说明:删除新表 ,Ij/
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drop table tabname ??LE0i
6、说明:增加一个列 9+8N-LZ
Alter table tabname add column col type bb+iUV|Do
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 f]C^{Uk#
7、说明:添加主键: Alter table tabname add primary key(col) - (q7"h
说明:删除主键: Alter table tabname drop primary key(col) et(AO)uv6
8、说明:创建索引:create [unique] index idxname on tabname(col....) " ub0}p4V
删除索引:drop index idxname r^ '
注:索引是不可更改的,想更改必须删除重新建。 RMid}BRE
9、说明:创建视图:create view viewname as select statement DK'S4%;Sp
删除视图:drop view viewname \C2HeA\#SW
10、说明:几个简单的基本的sql语句 Bt1v7M
选择:select * from table1 where 范围 79k+R9m
插入:insert into table1(field1,field2) values(value1,value2) P?jI:'u!R.
删除:delete from table1 where 范围 NF-@Q@
更新:update table1 set field1=value1 where 范围 4af^SZ)l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! `D$RL*C;M`
排序:select * from table1 order by field1,field2 [desc] j0n.+CO-{
总数:select count as totalcount from table1 )(c%QWz
求和:select sum(field1) as sumvalue from table1 |TF6&$>d
平均:select avg(field1) as avgvalue from table1 !kH 1|
最大:select max(field1) as maxvalue from table1 0,8RA_Ca}
最小:select min(field1) as minvalue from table1 C~nL3w
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11、说明:几个高级查询运算词 rZ.z!10
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A: UNION 运算符 SP>&+5AydX
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。 N-Bw&hEZ
B: EXCEPT 运算符 K!2%8Ej,J
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。 w6-<HPW<S
C: INTERSECT 运算符 |0X~D}r|J
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。 !\OX}kHX5
注:使用运算词的几个查询结果行必须是一致的。 *_HF %JYMZ
12、说明:使用外连接 # $'H?lO
A、left outer join: M!%|IKw
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。 -3m!970
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 t8.3
B:right outer join: afu!.}4Ct
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。 ,Vof<,x0
C:full outer join: }KNBqPo4B
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。 ZqjLZ9?q
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二、提升 Pmd5P:n*,
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) M7-2;MZ
法一:select * into b from a where 1<>1 "x0KiIoPk
法二:select top 0 * into b from a ?N@[R];
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) zH#urF6<
insert into b(a, b, c) select d,e,f from b; 9ESV[
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) .&8a ;Q?c
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 $ERiBALN:
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. :oiHf:
4、说明:子查询(表名1:a 表名2:b) %&s4YD/{
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) O3#eQs
5、说明:显示文章、提交人和最后回复时间 o]GZq..
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {M\n
6、说明:外连接查询(表名1:a 表名2:b) ;0uiO.
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8kE3\#);\
7、说明:在线视图查询(表名1:a ) l?Ibq} [~
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7?);wh 7`
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 T`]P5Bk8r
select * from table1 where time between time1 and time2 R D?52\
select a,b,c, from table1 where a not between 数值1 and 数值2
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9、说明:in 的使用方法 $s 'n]]Wq
select * from table1 where a [not] in ('值1','值2','值4','值6') ,"YTG*ky
10、说明:两张关联表,删除主表中已经在副表中没有的信息 JBLh4c3
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 6fCHd10!
11、说明:四表联查问题: M 5`hMfg
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 .....
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12、说明:日程安排提前五分钟提醒 x,fL656t
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 WSGho(\
13、说明:一条sql 语句搞定数据库分页 k<NxI\s8]
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 .S4%Q9l
14、说明:前10条记录 GLMpWD`Wo
select top 10 * form table1 where 范围 Dz8aJ6g
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.) }KEr@h,N
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) *u < ZQq
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 +/" \.wYv
(select a from tableA ) except (select a from tableB) except (select a from tableC) bU/YU0ZIT
17、说明:随机取出10条数据 'T;;-M3*
select top 10 * from tablename order by newid() -D%mVe)&+
18、说明:随机选择记录 Ry? f; s
select newid() ~mv5{C
19、说明:删除重复记录 N:Ir63X*#
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ksUF(lYk
20、说明:列出数据库里所有的表名 Q^* 33
select name from sysobjects where type='U' .>LJ(Sx9b
21、说明:列出表里的所有的 O]Yz7
select name from syscolumns where id=object_id('TableName') \l`{u)V
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。 bL+}n8B
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 6)>otB8)J
显示结果: ofPv?_@
type vender pcs vcaPd}nf
电脑 A 1 Wv~&Qh}
电脑 A 1 n9R0f9:*
光盘 B 2 =hY/Yr%P
光盘 A 2 4U u`1gtz
手机 B 3 I~;H'7|e
手机 C 3 -zI9E!24
23、说明:初始化表table1 5Yww,s
TRUNCATE TABLE table1 oY7jj=z#T
24、说明:选择从10到15的记录 tk>J
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 6qWWfm/6
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三、技巧 oArJ%Y>
1、1=1,1=2的使用,在SQL语句组合时用的较多 `;j$]
"where 1=1" 是表示选择全部 "where 1=2"全部不选, % iZM9Q&NC
如: l kyK
if @strWhere !='' 2IUd?i3~l
begin Ch:EL-L
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere nlaW$b{=
end P]armg%
else t+{vbS0
begin '|<S`,'#hg
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' &:1q3gDm
end \xQu*M:!
我们可以直接写成 7:<A_OLi
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere +oL@pp0
2、收缩数据库 \1QY=}
--重建索引 G.PRPl
DBCC REINDEX 'K#ndCGJ$
DBCC INDEXDEFRAG %joL}f[
--收缩数据和日志 JV_VM{w{K
DBCC SHRINKDB f[ia0w5 m
DBCC SHRINKFILE
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3、压缩数据库 DgY
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dbcc shrinkdatabase(dbname) sz%_9;`dpL
4、转移数据库给新用户以已存在用户权限 mkl^2V13~
exec sp_change_users_login 'update_one','newname','oldname' 1I)oT-~
go fPPmUM^C9
5、检查备份集 T''<y S
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' B&6lG!K'?
6、修复数据库 |68k9rq
ALTER DATABASE [dvbbs] SET SINGLE_USER i4nFjz
GO tBX71d
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK B-PX/Q
GO 5L_`Fw\l
ALTER DATABASE [dvbbs] SET MULTI_USER v G9>e&Be
GO "\=Phqw
7、日志清除 cLw|[!5:
SET NOCOUNT ON ? Dn}
DECLARE @LogicalFileName sysname, l@ (:Q!Sk
@MaxMinutes INT, \-f/\P/ w
@NewSize INT bZ``*{I/
USE tablename -- 要操作的数据库名 q alrG2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ivj=?[c|
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 4I&Mdt<^D
@NewSize = 1 -- 你想设定的日志文件的大小(M) u8M_2r
-- Setup / initialize beSU[
DECLARE @OriginalSize int XUD Ztxa
SELECT @OriginalSize = size gga}mqMv=
FROM sysfiles "F6gV;{Bt
WHERE name = @LogicalFileName /bPs0>5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + KSHq0A6/q%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + S4'<kF0z
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' *[|+5LVn
FROM sysfiles }W&9} 9p"
WHERE name = @LogicalFileName {8oGWQgrj
CREATE TABLE DummyTrans F\|4zM
(DummyColumn char (8000) not null) 1ANb=X|hig
DECLARE @Counter INT, b6p'%;Y/
@StartTime DATETIME, , 2xv
@TruncLog VARCHAR(255) N"suR}9%
SELECT @StartTime = GETDATE(), '2ZvK
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' i'4.w?O Z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) R<(xWH
EXEC (@TruncLog) 4 Tw~4b
-- Wrap the log if necessary. s~9n13z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Vu=/<;-N
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) C,GZ
AND (@OriginalSize * 8 /1024) > @NewSize t,IOq[Vtk
BEGIN -- Outer loop. 8ZLHN',
SELECT @Counter = 0 D9?.Ru0.
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]V_A4Df
BEGIN -- update Ip:54
INSERT DummyTrans VALUES ('Fill Log') wy0?*)~
DELETE DummyTrans #V%98|"
SELECT @Counter = @Counter + 1 v(!:HK0oeT
END YRFz]
EXEC (@TruncLog) B?- poB&
END -
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + 9 <{C9
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + =:]v~Ehq
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' :9Jy/7/
FROM sysfiles /zoy,t-i
WHERE name = @LogicalFileName ??U/Qi180
DROP TABLE DummyTrans \"Y,1in#
SET NOCOUNT OFF H-U_
8、说明:更改某个表 V)N{Fr)&
exec sp_changeobjectowner 'tablename','dbo' XmwAYf
9、存储更改全部表 u3GBAjPsIk
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ~BX=n9
@OldOwner as NVARCHAR(128), "WUS?Q
@NewOwner as NVARCHAR(128) m[74 p
AS 75lh07
DECLARE @Name as NVARCHAR(128) ^gZ,A]
DECLARE @Owner as NVARCHAR(128) d7
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DECLARE @OwnerName as NVARCHAR(128) /XEW]/4
DECLARE curObject CURSOR FOR JXYZ5&[
select 'Name' = name, > pP&/
'Owner' = user_name(uid) "=T&SY
from sysobjects dRnf
where user_name(uid)=@OldOwner XWyP'\
order by name \Z&Nd;o
OPEN curObject -THMTRFz
FETCH NEXT FROM curObject INTO @Name, @Owner 'A3skznX{
WHILE(@@FETCH_STATUS=0) fe,6YXUf
BEGIN =I)43ahd
if @Owner=@OldOwner ~~ rR< re
begin !hhL",
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~rJG4U
exec sp_changeobjectowner @OwnerName, @NewOwner |E.BGdS
end [nP s
-- select @name,@NewOwner,@OldOwner /:'>-253
FETCH NEXT FROM curObject INTO @Name, @Owner n2hV}t9O
END G0Qw&
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close curObject Vm>E F~ r
deallocate curObject >MYDwH
GO 9;?u%
10、SQL SERVER中直接循环写入数据 ~"CGur P
declare @i int }Mt1C~{(
set @i=1 7K:V<vX5
while @i<30 HP1QI/*v
begin \'4~@
insert into test (userid) values(@i) bAGKi.
set @i=@i+1 G9 O6Fi
end ow.!4kx{ d
小记存储过程中经常用到的本周,本月,本年函数 wz*iwd-
Dateadd(wk,datediff(wk,0,getdate()),-1) (Y@T5-!D
Dateadd(wk,datediff(wk,0,getdate()),6) $?G@ijk,
Dateadd(mm,datediff(mm,0,getdate()),0) |#kY_d)10
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) rUj\F9*5#
Dateadd(yy,datediff(yy,0,getdate()),0) q1( [mHZ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) n]ba1t8ZA
上面的SQL代码只是一个时间段 '=n?^EPE3
Dateadd(wk,datediff(wk,0,getdate()),-1) 4^F%bXJ)
Dateadd(wk,datediff(wk,0,getdate()),6) N+rU|iMa.
就是表示本周时间段. '#Au~5
下面的SQL的条件部分,就是查询时间段在本周范围内的: =I@t%Y
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) r(46jV.sD:
而在存储过程中 L2ydyXIsd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) K+F"V W*?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) _!@:@e)yB{