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。 d98ZC+q
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一、基础 hQfxz,X
1、说明:创建数据库 b|*A%?m
CREATE DATABASE database-name |3MqAvPJ
2、说明:删除数据库 i.Qy0
drop database dbname m+Yj"RMx&
3、说明:备份sql server g.N~81A
--- 创建 备份数据的 device <zK9J?ZQW>
USE master ,9f$an
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @BN cIJk9
--- 开始 备份 |f~p3KCfV
BACKUP DATABASE pubs TO testBack 'I_\ELb_
4、说明:创建新表 {^bs
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) r=+r5k"`
根据已有的表创建新表: H{P"$zj`l
A:create table tab_new like tab_old (使用旧表创建新表) M+ gYKPP
B:create table tab_new as select col1,col2... from tab_old definition only |vnfY;
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5、说明:删除新表 <c6C+OWT,
drop table tabname jn#
6、说明:增加一个列 <5~} !N X`
Alter table tabname add column col type Ee##:I[z
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。 b&!7(Q[ sT
7、说明:添加主键: Alter table tabname add primary key(col) Au,}5=+`P
说明:删除主键: Alter table tabname drop primary key(col) 56m|gZcC
8、说明:创建索引:create [unique] index idxname on tabname(col....) $vdGkz@6
删除索引:drop index idxname Z;W`deA
注:索引是不可更改的,想更改必须删除重新建。 fmvv
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9、说明:创建视图:create view viewname as select statement '+|{4-V
删除视图:drop view viewname m(8t |~S
10、说明:几个简单的基本的sql语句 @fbB3
选择:select * from table1 where 范围 H0s,tTK8
插入:insert into table1(field1,field2) values(value1,value2) g!O(@Sqp1
删除:delete from table1 where 范围 m4*Rr
更新:update table1 set field1=value1 where 范围 cV5Lp4wY?
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ?zN v7Bj
排序:select * from table1 order by field1,field2 [desc] (+ 9_nAgZ,
总数:select count as totalcount from table1 HQ+:0"B
求和:select sum(field1) as sumvalue from table1 xS,#TU;)Ol
平均:select avg(field1) as avgvalue from table1 GjA;o3(
最大:select max(field1) as maxvalue from table1 @M"h_Z1#
最小:select min(field1) as minvalue from table1 pVw)"\S%
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11、说明:几个高级查询运算词 u[^(s_
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A: UNION 运算符 M*E4:A9_M
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。 r$6z{Na\[
B: EXCEPT 运算符
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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。 fdCsn:
C: INTERSECT 运算符 M,PZ|=V6a
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。 BjJ$I^
注:使用运算词的几个查询结果行必须是一致的。 t.>vLzrU
12、说明:使用外连接 ;EE*#"IJ
A、left outer join: xk}YeNVj
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 OXzJ%&h
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Ni GK|Z
B:right outer join: 1z$;>+g<
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。 >0SF79-RE
C:full outer join: w'.ny<Pe
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。 Vl?R?K=`~J
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二、提升 oHbEHS61
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 'd1E~A
法一:select * into b from a where 1<>1 #Qy*zU#9
法二:select top 0 * into b from a Sz"J-3b^
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) gNzQ"W=
insert into b(a, b, c) select d,e,f from b; nKh._bvfX
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) kkFE9:[-c&
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6A/Nlk.
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^C@uP9g
4、说明:子查询(表名1:a 表名2:b) xZL`<3?
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) 6$b"tdP
5、说明:显示文章、提交人和最后回复时间 >wM%|j'
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b SA{A E9y
6、说明:外连接查询(表名1:a 表名2:b) ZsUxO%jP
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c :j
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7、说明:在线视图查询(表名1:a ) xue-5 '
select * from (SELECT a,b,c FROM a) T where t.a > 1; lb&tAl"D
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ?U2ed)zzw
select * from table1 where time between time1 and time2 }jfU qqFd
select a,b,c, from table1 where a not between 数值1 and 数值2 MlsF?"H p
9、说明:in 的使用方法 @=b0>^\m
select * from table1 where a [not] in ('值1','值2','值4','值6') Hv<%_t_/
10、说明:两张关联表,删除主表中已经在副表中没有的信息 l8%x(N4
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) iH(
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11、说明:四表联查问题: WUdKj
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... *6q8kQsz^1
12、说明:日程安排提前五分钟提醒 czb(&><
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 .F?yt5{5No
13、说明:一条sql 语句搞定数据库分页 Yq#I#
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 y^hpmTB3"
14、说明:前10条记录 lVXgp'!#j
select top 10 * form table1 where 范围 _jK\+Zf
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) HPCgv?E3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 7J,W#Ql)5
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 {{[).o/
(select a from tableA ) except (select a from tableB) except (select a from tableC) ^QB/{9 #
17、说明:随机取出10条数据 |RwD]2H
select top 10 * from tablename order by newid() CjOaw$s
18、说明:随机选择记录 B8|=P&L7N
select newid() o]}b#U8S
19、说明:删除重复记录 pt(GpbtWK
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) zV4%F"-
20、说明:列出数据库里所有的表名 [t<^WmgtxL
select name from sysobjects where type='U' #'^p-Jdm
21、说明:列出表里的所有的 Yiu)0\ o
select name from syscolumns where id=object_id('TableName') Q9 kKk
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`=ESz
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 27E6S)zv
显示结果: p2!x8`IB*
type vender pcs -deY,%
电脑 A 1 -d%bc?
电脑 A 1 H<%7aOwO2
光盘 B 2 o]MQ)\r
光盘 A 2 }%y_LcL
手机 B 3 xh@H@Q\
手机 C 3 ?9v!UT
23、说明:初始化表table1 y*\ M7}](
TRUNCATE TABLE table1 h^~eTi;c]Q
24、说明:选择从10到15的记录 ~0|~Fg
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc eOD;@4lR
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三、技巧 6}x^T)R
1、1=1,1=2的使用,在SQL语句组合时用的较多 `wB(J%w
"where 1=1" 是表示选择全部 "where 1=2"全部不选, vjZX8KAiZ
如: EiP_V&\
if @strWhere !='' 5xLuu KG
begin _myam3[W
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere !;'U5[}8
end ')bx1gc(?
else o&;+!Si@T
begin {NKDmeg:D
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' y= cBpC
end [_L:.,]g8
我们可以直接写成 ]Vl*!,(i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %I(N
2、收缩数据库
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--重建索引 O<iE,PN)
DBCC REINDEX r&1N8o
DBCC INDEXDEFRAG e@Z(z^V
--收缩数据和日志 6N~~:Gt
DBCC SHRINKDB yXppu[=
DBCC SHRINKFILE ^%#v
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3、压缩数据库 O jE wJ$$
dbcc shrinkdatabase(dbname) !z(POK
4、转移数据库给新用户以已存在用户权限 +%?_1bGX>
exec sp_change_users_login 'update_one','newname','oldname' Bu>srX9f
go )f(#Fn
5、检查备份集 -:a
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' iIcO_ZyA
6、修复数据库 "]kaaF$U%
ALTER DATABASE [dvbbs] SET SINGLE_USER V`S6cmwdc\
GO 8cfxKUS
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK uzho>p[ae
GO H `),PY2
ALTER DATABASE [dvbbs] SET MULTI_USER +X
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GO q^([ & +
7、日志清除 K}`.?6O
SET NOCOUNT ON ZaH<\`=%
DECLARE @LogicalFileName sysname, qK.8^{b
@MaxMinutes INT, jf*M}Q1jHE
@NewSize INT zg)Z2?K|;u
USE tablename -- 要操作的数据库名 t \DS}3pv
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 w;}P<K
@MaxMinutes = 10, -- Limit on time allowed to wrap log. s#)fnNQ,
@NewSize = 1 -- 你想设定的日志文件的大小(M) B\KvKT|\
-- Setup / initialize , YTuZS
DECLARE @OriginalSize int 1f~unb\Gg
SELECT @OriginalSize = size o`M7:8G
FROM sysfiles Xy_+L_h^
WHERE name = @LogicalFileName D7[ 8*^
SELECT 'Original Size of ' + db_name() + ' LOG is ' + #XQEfa
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 'Xxt[Jy
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ,hT t]w
FROM sysfiles 3PpycJ}
WHERE name = @LogicalFileName -zN*2T
CREATE TABLE DummyTrans QI=",vmau
(DummyColumn char (8000) not null) oSx]wZZ
DECLARE @Counter INT, _9Iz'-LgB
@StartTime DATETIME, oq^#mJL
@TruncLog VARCHAR(255) s$&:F4=?
SELECT @StartTime = GETDATE(), :f 1*-y
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 'r(}7>~fC
DBCC SHRINKFILE (@LogicalFileName, @NewSize) -XkCbxZ
EXEC (@TruncLog) Q;)[~p
-- Wrap the log if necessary. 'F5&f9A
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired qI^6}PB
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 3"6lPUS
AND (@OriginalSize * 8 /1024) > @NewSize u~bk~3.I
BEGIN -- Outer loop. lyF~E
SELECT @Counter = 0 DN;g2R`f
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) f lR6^6E
BEGIN -- update CbS- Rz:
INSERT DummyTrans VALUES ('Fill Log') D;.-e
DELETE DummyTrans jXSo{
SELECT @Counter = @Counter + 1 &}OaiTzEmc
END )f*&}SV
EXEC (@TruncLog) $*H_0w Qc
END pLDseEr<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ht!o_0{~
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + a+uSCs[C
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ",w@_}z:
FROM sysfiles ^UEI`_HO0
WHERE name = @LogicalFileName t}c ymX~
DROP TABLE DummyTrans P"XF|*^U
SET NOCOUNT OFF QuT8(s1Q!
8、说明:更改某个表 % E3
exec sp_changeobjectowner 'tablename','dbo' |k^'}n
9、存储更改全部表 =v:vc~G6
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch }NMA($@A
@OldOwner as NVARCHAR(128), DJS0;!#
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@NewOwner as NVARCHAR(128) ;Lu%v%BM
AS x5.HdKV
DECLARE @Name as NVARCHAR(128) pBL,kqYNA>
DECLARE @Owner as NVARCHAR(128) ^QpP'
DECLARE @OwnerName as NVARCHAR(128) 2h IM!wQ
DECLARE curObject CURSOR FOR Uk`ym
select 'Name' = name, i'H{cN6
'Owner' = user_name(uid) {SY@7G]
from sysobjects ~ZweP$l
where user_name(uid)=@OldOwner ]EnB`g(4;
order by name E<:XHjm
OPEN curObject ?k TVC
FETCH NEXT FROM curObject INTO @Name, @Owner }cn46L%/
WHILE(@@FETCH_STATUS=0) VY<$~9a&1
BEGIN 58DkVQ 6
if @Owner=@OldOwner Zz!XH8sH
begin O6pswMhAc
set @OwnerName = @OldOwner + '.' + rtrim(@Name) }JeGjpAcV
exec sp_changeobjectowner @OwnerName, @NewOwner g"EvMv&
end M/EEoK^K@
-- select @name,@NewOwner,@OldOwner )iNMjg
FETCH NEXT FROM curObject INTO @Name, @Owner 9s>q4_D
END WldlN?[j
close curObject }rj.N98
deallocate curObject 4c_TrNwP
GO Pv17wUB
10、SQL SERVER中直接循环写入数据 ~pO6C*"
declare @i int yH|[K=?S[
set @i=1 9E'fM
while @i<30 P(l$5x]g,
begin B5GT^DaT
insert into test (userid) values(@i) JF!JY( U,
set @i=@i+1 Ew5(U`]
end mKugb_d?
小记存储过程中经常用到的本周,本月,本年函数 b|^g51v
Dateadd(wk,datediff(wk,0,getdate()),-1) umaF}}-Q{
Dateadd(wk,datediff(wk,0,getdate()),6) Dq/_^a/1
Dateadd(mm,datediff(mm,0,getdate()),0) )a
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) -*~= 4m<
Dateadd(yy,datediff(yy,0,getdate()),0) `O?Kftv*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) i,r O3Jn
上面的SQL代码只是一个时间段 DzydS=`w
Dateadd(wk,datediff(wk,0,getdate()),-1) Hbu8gqu
Dateadd(wk,datediff(wk,0,getdate()),6) 48hu=,)81*
就是表示本周时间段. x$Y44v'>
下面的SQL的条件部分,就是查询时间段在本周范围内的: $N'AZY]4]
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ]-QY,
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而在存储过程中 ,pM~Phmp
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) J -tOO
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 7I;xRo|