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。 NX:\iJD)1U
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一、基础 >RpMw!NT
1、说明:创建数据库 k72NXagh
CREATE DATABASE database-name YNKvR
2、说明:删除数据库 +V[;DOlll
drop database dbname 'Z#>K*
3、说明:备份sql server zG^$-L.n
--- 创建 备份数据的 device tT]mMlKJ
USE master 5N bq9YY
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 1\)lD(J\C
--- 开始 备份 Nei i$
BACKUP DATABASE pubs TO testBack kVG+Wr7l0F
4、说明:创建新表 HnsLYY\
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Q:b0!
根据已有的表创建新表: HNlW.y"
A:create table tab_new like tab_old (使用旧表创建新表) $'<$:;4b3
B:create table tab_new as select col1,col2... from tab_old definition only VRSBf;?
5、说明:删除新表 *m`x/_y+
drop table tabname eYUq0~3
6、说明:增加一个列 lk
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Alter table tabname add column col type ua_,c\iL
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。 W%o! m,zFM
7、说明:添加主键: Alter table tabname add primary key(col) A0v@L6m-O
说明:删除主键: Alter table tabname drop primary key(col) *Gj`1#Z$
8、说明:创建索引:create [unique] index idxname on tabname(col....) Ag8lI+
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删除索引:drop index idxname :/t_5QN
注:索引是不可更改的,想更改必须删除重新建。 8|5+\1!#/)
9、说明:创建视图:create view viewname as select statement 6Lg#co}9
删除视图:drop view viewname C#3&,G W
10、说明:几个简单的基本的sql语句 0V`~z-#
选择:select * from table1 where 范围 F|o1r
插入:insert into table1(field1,field2) values(value1,value2) NdXC8
删除:delete from table1 where 范围 R9QW%!:,\2
更新:update table1 set field1=value1 where 范围 d5R2J:dI
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %Q;:nVt
排序:select * from table1 order by field1,field2 [desc] mC?}:WM@
总数:select count as totalcount from table1 1|:;~9n<t
求和:select sum(field1) as sumvalue from table1 uX&h~qE/
平均:select avg(field1) as avgvalue from table1 lZ <D,&
最大:select max(field1) as maxvalue from table1 2^:iU{
最小:select min(field1) as minvalue from table1 If8
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11、说明:几个高级查询运算词 3Ljj|5.q
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A: UNION 运算符 G9K& }_,
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。 >enP~uW[#
B: EXCEPT 运算符 ,_=LV
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。 ?`6Mfpvj96
C: INTERSECT 运算符 &>K|F >7q
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。 IMpL+W.
注:使用运算词的几个查询结果行必须是一致的。 ~SsfkM"
12、说明:使用外连接 |t;Ktl
A、left outer join: Ay%]l| Gm
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。 nB5^
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 g9d/nRX&
B:right outer join: D}-HWJQA3
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。 P*hYh5a
C:full outer join: bQI.Qk
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。 1 CV?
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二、提升 {>TAnb?n
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) N4{g[[ T
法一:select * into b from a where 1<>1 A.r.tf}:
法二:select top 0 * into b from a m2ph8KC
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Hd
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insert into b(a, b, c) select d,e,f from b; :?i,!0#"
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) F*NHy.Y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (/t{z=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. fWDTP|DV
4、说明:子查询(表名1:a 表名2:b) gT,iH.
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) (IA:4E}
5、说明:显示文章、提交人和最后回复时间 -OKXfN]
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b U<'z,Px6
6、说明:外连接查询(表名1:a 表名2:b) IA}.{zY~|
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2|`Mb~E;
7、说明:在线视图查询(表名1:a ) s=z$;1C
select * from (SELECT a,b,c FROM a) T where t.a > 1; u~mpZ"9$ 3
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 I+jc
select * from table1 where time between time1 and time2 |O"Pb`V+
select a,b,c, from table1 where a not between 数值1 and 数值2 'gsO}xj
9、说明:in 的使用方法 yHZ&5
select * from table1 where a [not] in ('值1','值2','值4','值6') Wv,?xm
10、说明:两张关联表,删除主表中已经在副表中没有的信息 %(s2{$3
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ma"M? aM
11、说明:四表联查问题: A v;NQt8ut
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 1 7iw`@
12、说明:日程安排提前五分钟提醒 Y'R/|:YL@
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 c^5fhmlt
13、说明:一条sql 语句搞定数据库分页 twa H20
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 2&AX_#P
14、说明:前10条记录 Q2Uk0:M
select top 10 * form table1 where 范围 <YCR^?hJSi
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) i=fhK~Jd
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) gxC`Ml
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 :z|$K^)7Z
(select a from tableA ) except (select a from tableB) except (select a from tableC) W4h ]4X
17、说明:随机取出10条数据 Z hCjY
select top 10 * from tablename order by newid() )_?H BTG
18、说明:随机选择记录 UCo<ie\V
select newid() j2 >WHh
19、说明:删除重复记录 K;TTGK
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) (@O,U
20、说明:列出数据库里所有的表名 yC!>7@m
select name from sysobjects where type='U' D?H|O[
21、说明:列出表里的所有的 x'%vL",%
select name from syscolumns where id=object_id('TableName') 8*uaI7;*
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。 !&v"+ K3lU
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 9R&.$5[W(s
显示结果: |;U3pq)
type vender pcs eV0eMDY5
电脑 A 1 *;lb<uLv
电脑 A 1 xz7CnW1
光盘 B 2 F^=y+}]=
光盘 A 2 jo0XOs
手机 B 3 /u"Iq8QA
手机 C 3 Ie8K[ >
23、说明:初始化表table1 jd`]]FAww
TRUNCATE TABLE table1 NG4@L1f%
24、说明:选择从10到15的记录 7&V3f=aj6
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc x3jjtjf
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三、技巧 &G3$q,`H
1、1=1,1=2的使用,在SQL语句组合时用的较多 }UG<_bE|
"where 1=1" 是表示选择全部 "where 1=2"全部不选, (YYwn@NGj
如: 'sk M$jr
if @strWhere !='' ;b_<5S
begin vgr5j
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ^vOEG;TR<-
end 5?E;YyA
else ZCfd<NS?
begin clIn}wQ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' X{h[
end 2D3mTpw
我们可以直接写成 Ka"1gbJ|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere oV~S4|9:
2、收缩数据库 z qd1G(tO
--重建索引 g+C~}M_7
DBCC REINDEX CY!H)6k
DBCC INDEXDEFRAG (W9 K:]}
--收缩数据和日志 7?
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DBCC SHRINKDB w&&)v~Y_
DBCC SHRINKFILE .O{_^~w_q
3、压缩数据库 mx2Ov u
dbcc shrinkdatabase(dbname) 7~H$p X
4、转移数据库给新用户以已存在用户权限 ;$4:
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exec sp_change_users_login 'update_one','newname','oldname' M%Q_;\?]
go AJP-7PPD
5、检查备份集 [-#q'S
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' _IvqZ/6Y(
6、修复数据库 cZw_^@!
ALTER DATABASE [dvbbs] SET SINGLE_USER u$ ^r(.EV
GO :QMpp}G
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9*CRMkPrd
GO %V-Hy ;V
ALTER DATABASE [dvbbs] SET MULTI_USER C{V,=Fo^
GO GbC JGqOR
7、日志清除 }5QUIK~NA
SET NOCOUNT ON U(<~("ocN
DECLARE @LogicalFileName sysname, `3dGn.M
@MaxMinutes INT, n." XiXsN
@NewSize INT k{^iv:
USE tablename -- 要操作的数据库名 O*Z-3l
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 *uF Iw}C/
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 01+TVWKX
@NewSize = 1 -- 你想设定的日志文件的大小(M) R>,_C7]u
-- Setup / initialize '5 9{VA6h
DECLARE @OriginalSize int *
a VT
SELECT @OriginalSize = size c>#3{}X|x%
FROM sysfiles #5^S@}e
WHERE name = @LogicalFileName >V&GL{
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <?!%dV{z
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Q1DiEg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' IXR%IggJA
FROM sysfiles ,u.A[{@py
WHERE name = @LogicalFileName `>k7^!Ds
CREATE TABLE DummyTrans P0-K/_g
(DummyColumn char (8000) not null) 1]7v3m
DECLARE @Counter INT, p4Xhs@.k
@StartTime DATETIME, ;O({|mpS\
@TruncLog VARCHAR(255) : Z3]Dk;y
SELECT @StartTime = GETDATE(), nTz(
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' d s}E|Q
DBCC SHRINKFILE (@LogicalFileName, @NewSize) e.;B?0QrV
EXEC (@TruncLog) l_T5KV
-- Wrap the log if necessary. k|
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Dwah_ p8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) vVbS
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AND (@OriginalSize * 8 /1024) > @NewSize u4:6zU/{
BEGIN -- Outer loop. '5P:;zw
SELECT @Counter = 0 :U'Oc3l#Y
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) c+UZ UgP
BEGIN -- update ~fz9PoC
INSERT DummyTrans VALUES ('Fill Log') I -V=Z:
DELETE DummyTrans z*/}rk4i
SELECT @Counter = @Counter + 1 sfCU"O2G
END ^<Sy{KY
EXEC (@TruncLog) t\-;n:p-
END [}"m4+
SELECT 'Final Size of ' + db_name() + ' LOG is ' + XJ?zP=UK
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + (gUxS.zU
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' hDTM\>.c;s
FROM sysfiles <A]
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WHERE name = @LogicalFileName nD{{/_"'
DROP TABLE DummyTrans ]Q{MF- EKj
SET NOCOUNT OFF XC[bEp$
8、说明:更改某个表 <+ckE2j
exec sp_changeobjectowner 'tablename','dbo' 5Ja[p~^L
9、存储更改全部表 G 2FD'Sf
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch WL<f!
@OldOwner as NVARCHAR(128), PE2O$:b\
@NewOwner as NVARCHAR(128) U~<~>^[
AS HhB'
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DECLARE @Name as NVARCHAR(128) w?M` gl8r
DECLARE @Owner as NVARCHAR(128) >jm^MS=
DECLARE @OwnerName as NVARCHAR(128) !JPZ7_nn
DECLARE curObject CURSOR FOR qD5)AdCGO
select 'Name' = name, uBo~PiJ2"
'Owner' = user_name(uid) #!]~E@;E
from sysobjects OH vV_
where user_name(uid)=@OldOwner ;VPYWss
order by name ljk,R
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OPEN curObject B..> *Xb
FETCH NEXT FROM curObject INTO @Name, @Owner zR }vw{
WHILE(@@FETCH_STATUS=0) @}A3ie'w
BEGIN uSNlI78D
if @Owner=@OldOwner 8Y~\:3&1<
begin ~G8haN4
set @OwnerName = @OldOwner + '.' + rtrim(@Name) <f@
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exec sp_changeobjectowner @OwnerName, @NewOwner -KiI&Q
end O[HBw~
-- select @name,@NewOwner,@OldOwner 7u[$
FETCH NEXT FROM curObject INTO @Name, @Owner lBOxB/`
END ?xzDz
close curObject s"0Hz"[^=
deallocate curObject r?=3TAA
GO nb U?:=P
10、SQL SERVER中直接循环写入数据 jGOE
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declare @i int 4Kn)5>
set @i=1 :&$WWv
while @i<30 )<^G]ajn
begin VJ|80?4h
insert into test (userid) values(@i) !FbW3p f
set @i=@i+1 l AZBlO
end z6bIv}
小记存储过程中经常用到的本周,本月,本年函数 #|acRZ9
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Dateadd(wk,datediff(wk,0,getdate()),-1) -o`|A767
Dateadd(wk,datediff(wk,0,getdate()),6) $R/@%U)-o
Dateadd(mm,datediff(mm,0,getdate()),0) WD?COUEox
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &^])iG,Ew
Dateadd(yy,datediff(yy,0,getdate()),0) 9lSs;zm{Q
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) `:EU~4s\
上面的SQL代码只是一个时间段 IFF3gh42.
Dateadd(wk,datediff(wk,0,getdate()),-1) (Z at|R.F
Dateadd(wk,datediff(wk,0,getdate()),6) ;%$wA5"2M
就是表示本周时间段. G'6f6i|<I@
下面的SQL的条件部分,就是查询时间段在本周范围内的: `'/1Ij+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) >twog}%
而在存储过程中 6g%~~hX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ,\0>d}eh!
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6)
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