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。 Fc~'TBf,,`
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一、基础 QM3,'?ekRH
1、说明:创建数据库 f|^dD`
CREATE DATABASE database-name 5MFxo63
2、说明:删除数据库 ,jXM3?>B
drop database dbname O^/Maa/D1
3、说明:备份sql server FMkOo2{
--- 创建 备份数据的 device A7(hw~+@
USE master u` oq(?|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Fk(JSiU
--- 开始 备份 ?)bS['^1)
BACKUP DATABASE pubs TO testBack |mdi]TL
4、说明:创建新表 kb[P\cRa
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) iA8U Yd3Q
根据已有的表创建新表: >=]'hyn]]
A:create table tab_new like tab_old (使用旧表创建新表) f;/QJ
B:create table tab_new as select col1,col2... from tab_old definition only /Q,{?';~
5、说明:删除新表 }2K $^uR
drop table tabname c/B'jPt
6、说明:增加一个列 66^ycZCH
Alter table tabname add column col type &1+X\c+tb
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。
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7、说明:添加主键: Alter table tabname add primary key(col) qwIa?!8o
说明:删除主键: Alter table tabname drop primary key(col) 4iW'kuK
8、说明:创建索引:create [unique] index idxname on tabname(col....) D:Q
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删除索引:drop index idxname *Z m^
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注:索引是不可更改的,想更改必须删除重新建。 )tCX
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9、说明:创建视图:create view viewname as select statement -n'F v@U
删除视图:drop view viewname )c l5B{1P
10、说明:几个简单的基本的sql语句 aM7uBx\8 5
选择:select * from table1 where 范围 >A0k 8T
插入:insert into table1(field1,field2) values(value1,value2) "NgoaG~!YO
删除:delete from table1 where 范围 PrudhUI^
更新:update table1 set field1=value1 where 范围 rr#K"SP
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Vd=yr'?
排序:select * from table1 order by field1,field2 [desc] =6aS&B(SN
总数:select count as totalcount from table1 .VTy[|o
求和:select sum(field1) as sumvalue from table1 K}6dg<
平均:select avg(field1) as avgvalue from table1 Cy*|&=>j
最大:select max(field1) as maxvalue from table1 l>Ub!^;
最小:select min(field1) as minvalue from table1 0IQ'3_
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11、说明:几个高级查询运算词 F:6SPY
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A: UNION 运算符 FQ>`{%>
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}\[Gr
B: EXCEPT 运算符 q>w)"Dd
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。 cBo{/Tn:
C: INTERSECT 运算符 }K8/-d6
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。 wvrrMGU)a
注:使用运算词的几个查询结果行必须是一致的。 #
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12、说明:使用外连接 JHf
A、left outer join: *D'$"@w3
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 4%1D}9hO6
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c rQ=,y>-*
B:right outer join: U^qt6$bK
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。 S1/`th
C:full outer join: " R8KQj
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。 Hcc"b0>}{
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二、提升 ;Ag
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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) _-5,zPR
法一:select * into b from a where 1<>1 rp5(pV7*
法二:select top 0 * into b from a <cA/<3k)
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) o[H{(f1%
insert into b(a, b, c) select d,e,f from b; %F kMv
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) v\`9;QV5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 p-+K4
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 8EVgoJ.
4、说明:子查询(表名1:a 表名2:b) "_2Ng<2
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)
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5、说明:显示文章、提交人和最后回复时间 TNQP"9[?
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b s}pIk.4ot!
6、说明:外连接查询(表名1:a 表名2:b) D1nq2GwS
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c w,R[C\#J
7、说明:在线视图查询(表名1:a ) !?^b[
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select * from (SELECT a,b,c FROM a) T where t.a > 1; 2>*%q%81
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 e[Abp~@M1
select * from table1 where time between time1 and time2 H5D*|42
select a,b,c, from table1 where a not between 数值1 and 数值2 -48vJR*tC
9、说明:in 的使用方法 vP+@z-O
select * from table1 where a [not] in ('值1','值2','值4','值6') g@\fZTO
10、说明:两张关联表,删除主表中已经在副表中没有的信息
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) @-OnHE
11、说明:四表联查问题: k1VT /u
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 ..... V^Hu3aUx8
12、说明:日程安排提前五分钟提醒 =}PdH`S
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 .'a&33J
13、说明:一条sql 语句搞定数据库分页 )]#aa uC+
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 Z@Ae$ '9H
14、说明:前10条记录 5XLs} :
select top 10 * form table1 where 范围 b=3H
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.) _,</1~.
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) nNXgW
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 *'"^NSJ
(select a from tableA ) except (select a from tableB) except (select a from tableC) |AC1\)2tT
17、说明:随机取出10条数据 '_b.\_s-d
select top 10 * from tablename order by newid() y*MF&mQ[
18、说明:随机选择记录 ]jpu,jz:
select newid() f-nz{U
19、说明:删除重复记录 Y'e eA 2O
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) \p%3vRwS%p
20、说明:列出数据库里所有的表名 sZ?mP;Q
select name from sysobjects where type='U' :a:l
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21、说明:列出表里的所有的 #Wu*3&a]yU
select name from syscolumns where id=object_id('TableName')
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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。 ~n}k\s~|4
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 :$+-3_oLMQ
显示结果: S(:l+JP
type vender pcs t20PP4FWM
电脑 A 1 ^*\XgX
电脑 A 1 a6kV!,.U
光盘 B 2 <'G~8tA%v
光盘 A 2 ~ H6r.:]
手机 B 3 _4 cvX
手机 C 3 <_(/X,kBK
23、说明:初始化表table1 c)0amM
TRUNCATE TABLE table1 $wYFEz
24、说明:选择从10到15的记录 >hH0Q5aL
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,ZS6jZ
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三、技巧 ](F#`zUQ
1、1=1,1=2的使用,在SQL语句组合时用的较多 9_sA&2P{uV
"where 1=1" 是表示选择全部 "where 1=2"全部不选, rxme(9M
如: MQ)L:R`L
if @strWhere !='' sdCvG R e
begin P=1I<Pew
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere J9T3nTfL
end %6--}bY^
else M# 18H<]
begin .@-$5Jw
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' qaim6a
end 21RP=0Q:
我们可以直接写成 t*@z8<H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere KgN)JD>
2、收缩数据库 ps$7bN C
--重建索引 LK"
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DBCC REINDEX fIGFHZy,
DBCC INDEXDEFRAG e|4&b@
--收缩数据和日志 *._|- L
DBCC SHRINKDB Dup;e&9g
DBCC SHRINKFILE .d/:30Y
3、压缩数据库 PQ|69*2G
dbcc shrinkdatabase(dbname) 7w;O}axI
4、转移数据库给新用户以已存在用户权限 2BCtJ`S`
exec sp_change_users_login 'update_one','newname','oldname' 5sPywk{
go LI)!4(WH
5、检查备份集 ,
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' +\Q?w?DE|
6、修复数据库 m*X[ Jtr
ALTER DATABASE [dvbbs] SET SINGLE_USER 'B0{U4?
GO |w}xl'>q
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK _tr<}PnZ
GO U}SXJH&&E
ALTER DATABASE [dvbbs] SET MULTI_USER a(]`F(L
GO L !4t[hhe=
7、日志清除 Q!,<@b)
SET NOCOUNT ON $;G{Pyp
DECLARE @LogicalFileName sysname, /=uMk]h
@MaxMinutes INT, Vx_rc%'
@NewSize INT f.GETw
USE tablename -- 要操作的数据库名 a{Esw`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ;IK[Y{W/
@MaxMinutes = 10, -- Limit on time allowed to wrap log. rw)kAe31
@NewSize = 1 -- 你想设定的日志文件的大小(M) 0ult7s}
-- Setup / initialize /J)l /oI
DECLARE @OriginalSize int Jw~( G9G
SELECT @OriginalSize = size ``ekR6[ 8c
FROM sysfiles *Ywpz^2?:
WHERE name = @LogicalFileName T!W~n
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + sS
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + aAu>Tn86D.
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' -yDs<
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FROM sysfiles .k4W_9
WHERE name = @LogicalFileName `bKA+c,f
CREATE TABLE DummyTrans D\/xu-&
(DummyColumn char (8000) not null) NrDi
DECLARE @Counter INT, @5)
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@StartTime DATETIME, xyr+_k-x&q
@TruncLog VARCHAR(255) (wmBjQ]B<
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 9{j66
DBCC SHRINKFILE (@LogicalFileName, @NewSize) c.\O/N
EXEC (@TruncLog) 2}?wYI*:5|
-- Wrap the log if necessary. *]J dHO
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 7t9c7HLuj/
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) gqib:q;r
AND (@OriginalSize * 8 /1024) > @NewSize W\f9jfD
BEGIN -- Outer loop. ?GaI6?lbn
SELECT @Counter = 0 5P5A,K
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `</=AY>
BEGIN -- update cKvAR5|
INSERT DummyTrans VALUES ('Fill Log') xg*\j)_}
DELETE DummyTrans vWPM:1A
SELECT @Counter = @Counter + 1 )&b}^1
END }.fZy&_
EXEC (@TruncLog) duZ|mT8Q==
END Gd]5xl
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + f}evw K[S
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + (1saof*p%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' llTQ\7zP
FROM sysfiles i}
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WHERE name = @LogicalFileName E-5ij,bHv3
DROP TABLE DummyTrans |IyM"UH
SET NOCOUNT OFF MX4 :e>dtd
8、说明:更改某个表 Fyi?,,
exec sp_changeobjectowner 'tablename','dbo' 7$Z)fkx.
9、存储更改全部表 JO<gN=
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8o%<.]
@OldOwner as NVARCHAR(128), )zk?yY6
@NewOwner as NVARCHAR(128) S?,KgMVM
AS HlOAo:8'
DECLARE @Name as NVARCHAR(128) Q+y-*1
DECLARE @Owner as NVARCHAR(128) di)noQXkB-
DECLARE @OwnerName as NVARCHAR(128) !DY2{Wb
DECLARE curObject CURSOR FOR ?vL^:f["
select 'Name' = name, 4X(1
'Owner' = user_name(uid) On2Vf*G@|
from sysobjects ]XpU'/h>q;
where user_name(uid)=@OldOwner 1A)wbH)
order by name U:etcnb4w>
OPEN curObject |2+F I<v4
FETCH NEXT FROM curObject INTO @Name, @Owner eJVOVPg<,
WHILE(@@FETCH_STATUS=0) $Nt]${0
BEGIN mTb2d?NS
if @Owner=@OldOwner n'x`oI)-
begin g[D,\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) nCSd:1DY
exec sp_changeobjectowner @OwnerName, @NewOwner ShsP]$Yp
end -67f33
-- select @name,@NewOwner,@OldOwner /FNj|7s
FETCH NEXT FROM curObject INTO @Name, @Owner yoQ?lh
END i+T0}M<
close curObject wzLiVe-
deallocate curObject &s6(3k
GO *fuGVA
10、SQL SERVER中直接循环写入数据 ]mJAKycE%
declare @i int [u9S+:7"
set @i=1 +2k|g2
while @i<30 7Hr4yh[j&
begin d= T9mj.@
insert into test (userid) values(@i) pFv[z':&Q
set @i=@i+1 (>Q9jNW
end ~:RDw<PWp
小记存储过程中经常用到的本周,本月,本年函数 R^Eu}?<f
Dateadd(wk,datediff(wk,0,getdate()),-1) TF}4X;3Dsy
Dateadd(wk,datediff(wk,0,getdate()),6) N-?|]4e/
Dateadd(mm,datediff(mm,0,getdate()),0) ekk&TTp#
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7gR;
Dateadd(yy,datediff(yy,0,getdate()),0)
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2M(PH]D
上面的SQL代码只是一个时间段 Y[8co<p
Dateadd(wk,datediff(wk,0,getdate()),-1) c402pj
Dateadd(wk,datediff(wk,0,getdate()),6) U*+!w@
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就是表示本周时间段. :Ro"
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下面的SQL的条件部分,就是查询时间段在本周范围内的: 'y@ 2,9v
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ^>R| R1&
而在存储过程中 |EEz>ci
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) H|Fqc=qp
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0f#a_