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。 &Wz:-G7<n
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一、基础 PjZvLK@a9)
1、说明:创建数据库 J*&=J6
CREATE DATABASE database-name /~huTKA}
2、说明:删除数据库 LF.~rmPa
drop database dbname HtYR 0J
3、说明:备份sql server 4m!3P"$
--- 创建 备份数据的 device j?hyN@ns
USE master pz}hh^]t
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' tUF]f6
--- 开始 备份 Zw
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BACKUP DATABASE pubs TO testBack bK%tQeT
4、说明:创建新表 KBHKcFk
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) /r@
根据已有的表创建新表: YgOgYo{E!
A:create table tab_new like tab_old (使用旧表创建新表) L=!kDU
B:create table tab_new as select col1,col2... from tab_old definition only QGG(I7{-
5、说明:删除新表 3CuoBb8
drop table tabname @wJa33QT
6、说明:增加一个列 S,v >*AF
Alter table tabname add column col type 8B+^vF
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。 _H<OfAO
7、说明:添加主键: Alter table tabname add primary key(col) J$*["y`+
说明:删除主键: Alter table tabname drop primary key(col) `2,_"9Z(
8、说明:创建索引:create [unique] index idxname on tabname(col....) J,KTc'[
删除索引:drop index idxname -mo
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注:索引是不可更改的,想更改必须删除重新建。 vUx$[/<
9、说明:创建视图:create view viewname as select statement T\CQ
删除视图:drop view viewname @Hdg-f>y]
10、说明:几个简单的基本的sql语句 (`/i1#nR
选择:select * from table1 where 范围 Z@O
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插入:insert into table1(field1,field2) values(value1,value2) 6v)eM=
删除:delete from table1 where 范围 ^F9zS`Yz2
更新:update table1 set field1=value1 where 范围 R*eM 1
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 2#}IGZ`Yp/
排序:select * from table1 order by field1,field2 [desc] qA/3uA!z
总数:select count as totalcount from table1 b+apN ph
求和:select sum(field1) as sumvalue from table1 `^k<.O
平均:select avg(field1) as avgvalue from table1 MtTHKp
最大:select max(field1) as maxvalue from table1 L>GYj6D9
最小:select min(field1) as minvalue from table1 O[B_7
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11、说明:几个高级查询运算词 zb,`K*Z{
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A: UNION 运算符 8>;o MM
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。 Yx c >+mx
B: EXCEPT 运算符 3-%~{(T/
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。 @soW f
C: INTERSECT 运算符 vJ}
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。 {j*+:Gj0V
注:使用运算词的几个查询结果行必须是一致的。 9gayu<J
12、说明:使用外连接 IFoN<<7/2$
A、left outer join: oioN0EuDk
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。 Ps4A
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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 ` &7?+s
B:right outer join: ]r5Xp#q2
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。 1K',Vw_
C:full outer join: iqP0=(^m
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。 xl=|]8w
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二、提升 {z
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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) Gfch|Q^INy
法一:select * into b from a where 1<>1 !`E2O*g
法二:select top 0 * into b from a '-TFr NO;h
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) o|E(_Y4d
insert into b(a, b, c) select d,e,f from b; Kx!|4ya,
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) scwlW
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 s_kd@?=`x
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 1&E&8In]$r
4、说明:子查询(表名1:a 表名2:b) P"<ad
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) H8k| >4
5、说明:显示文章、提交人和最后回复时间 .W:], 5e
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b cu|q&
6、说明:外连接查询(表名1:a 表名2:b) 'Q,<_L"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8Wp1L0$B
7、说明:在线视图查询(表名1:a ) CMUphS-KE
select * from (SELECT a,b,c FROM a) T where t.a > 1; `&JA7UD>
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 Py<vN!
select * from table1 where time between time1 and time2 <-7Ha_#
select a,b,c, from table1 where a not between 数值1 and 数值2 x9s`H)
9、说明:in 的使用方法 13
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select * from table1 where a [not] in ('值1','值2','值4','值6') ]2
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 K2v)"|T)
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) {a%cU[q
11、说明:四表联查问题: FQ^uX]<3j
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 ..... ^S$w,
12、说明:日程安排提前五分钟提醒 5OE?;PJ(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ?q`mr_x%?
13、说明:一条sql 语句搞定数据库分页 wO
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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 l]cQ7g5
14、说明:前10条记录 $yJfAR
select top 10 * form table1 where 范围 ga%77t|jm3
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Q"uu&JC
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) B`Pi\1H6%
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 B)*%d7=x
(select a from tableA ) except (select a from tableB) except (select a from tableC) NYRNop( N#
17、说明:随机取出10条数据 UkQocZdZ
select top 10 * from tablename order by newid() FiL
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18、说明:随机选择记录 qILr+zH
select newid() 5J3kQ;5Q?
19、说明:删除重复记录 '-{jn+,
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2V 'Tt3
20、说明:列出数据库里所有的表名 =z.AQe+
select name from sysobjects where type='U' 6Wp:W1E{`
21、说明:列出表里的所有的 =wc[r?7
select name from syscolumns where id=object_id('TableName') Hq8.O/Y"=
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 G9Ezm*I;:
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ST.W{:X
显示结果: r&;AG@N/
type vender pcs O[5ti=W
电脑 A 1 )I_I?e
电脑 A 1 ;rbn/6
光盘 B 2 E"!*ASN
光盘 A 2 beoMLHp
手机 B 3 so?1lG
手机 C 3 `dhK$jYD
23、说明:初始化表table1 "w1jr 6"
TRUNCATE TABLE table1 f}4h}Cq
24、说明:选择从10到15的记录 hG]20n2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc E}+A)7mA
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三、技巧 CJ b~~
1、1=1,1=2的使用,在SQL语句组合时用的较多 cj)~7 WF
"where 1=1" 是表示选择全部 "where 1=2"全部不选, eS|p3jk;
如: 2"T&Fp<
if @strWhere !='' @hv]
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begin -Zh+5;8g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere f5v|}gMAX
end *']RYu?X
else @ck2j3J/
begin 6dp~19T^
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' To+{9"$,
end 8*ysuL#
我们可以直接写成 xPv&(XZR
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere nq;)!Wry
2、收缩数据库 U_?RN)>j
--重建索引 b04~z&Xv
DBCC REINDEX B~IOM
DBCC INDEXDEFRAG fA^ O
--收缩数据和日志 ub%q<sE*
DBCC SHRINKDB vPi+8)
DBCC SHRINKFILE l=yO]a\QZ
3、压缩数据库 ?{V[bm
dbcc shrinkdatabase(dbname) |r%P.f:y{X
4、转移数据库给新用户以已存在用户权限 ~+Y;jAdU
exec sp_change_users_login 'update_one','newname','oldname' $- L)>"
go s*@.qN
5、检查备份集 w;"'l]W
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' f &|SGD*
6、修复数据库 5P4>xv[
ALTER DATABASE [dvbbs] SET SINGLE_USER CT : ac64
GO |bh:x{h
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK LY MfoXp
GO 8V nZ@*
ALTER DATABASE [dvbbs] SET MULTI_USER UJI1n?~
GO RK0IkRXQd
7、日志清除 6lPGop]js]
SET NOCOUNT ON Q=[&~^Y)
DECLARE @LogicalFileName sysname, C-7.Sa
@MaxMinutes INT, `i-&Z`
@NewSize INT ]iPdAwc.1
USE tablename -- 要操作的数据库名 %rsW:nl
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ]pt @
@MaxMinutes = 10, -- Limit on time allowed to wrap log. S@_GjCpn
@NewSize = 1 -- 你想设定的日志文件的大小(M) ?@#<>7V
-- Setup / initialize nC w1H kW
DECLARE @OriginalSize int %K%z<R8
SELECT @OriginalSize = size c-,/qn/
FROM sysfiles LQe<mZ<
WHERE name = @LogicalFileName ]=/f`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _Z%C{~,7)x
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8LL);"$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' >9DgsA`'
FROM sysfiles AjpQb~\
WHERE name = @LogicalFileName 1g@kHq
CREATE TABLE DummyTrans lUrchLoDt
(DummyColumn char (8000) not null) rRMC<.=
DECLARE @Counter INT, vDemY"wz
@StartTime DATETIME, S=o/n4@}
@TruncLog VARCHAR(255) E5rNC/Ul$$
SELECT @StartTime = GETDATE(), pD{Li\LY
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1+]e?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ,70|I{,Km
EXEC (@TruncLog) @!-= :<h
-- Wrap the log if necessary. k~H-:@
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired /{lls2ycW%
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ]ba<4:[Go
AND (@OriginalSize * 8 /1024) > @NewSize #f[yp=uI:
BEGIN -- Outer loop.
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SELECT @Counter = 0 R_lNC]b0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) CyE.q^Wm
BEGIN -- update ]}9EBf
INSERT DummyTrans VALUES ('Fill Log') iU &V}p
DELETE DummyTrans :%Bo)0a9
SELECT @Counter = @Counter + 1 5<u+2x8|
END (GZm+?
EXEC (@TruncLog) g\ke,r6
END 7>.^GD
SELECT 'Final Size of ' + db_name() + ' LOG is ' + +}^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + '=oV
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' QF>H>=Za=
FROM sysfiles P<bA~%<7"[
WHERE name = @LogicalFileName (T@ov~@
DROP TABLE DummyTrans te1lUQ
SET NOCOUNT OFF A2B&X}K|U
8、说明:更改某个表 8!1o,=I$
exec sp_changeobjectowner 'tablename','dbo' % R'eV<
9、存储更改全部表 3vy5JTCz~
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch j"f]pzg&
@OldOwner as NVARCHAR(128), )%Y$FLB
@NewOwner as NVARCHAR(128) XOxm<3gXn
AS UZ
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DECLARE @Name as NVARCHAR(128) NoMEe<
DECLARE @Owner as NVARCHAR(128) S"lcePN
DECLARE @OwnerName as NVARCHAR(128) f6DPah#
DECLARE curObject CURSOR FOR Dhq7qz
select 'Name' = name, ;$86.2S>B
'Owner' = user_name(uid) f1JvP\I0Q
from sysobjects fd(>[RP?
where user_name(uid)=@OldOwner <{'':/tXI
order by name
BYu|loc
OPEN curObject e Q0bx&
FETCH NEXT FROM curObject INTO @Name, @Owner ?L_#AdK
WHILE(@@FETCH_STATUS=0) *FO']D
BEGIN ~Su>^T(?-
if @Owner=@OldOwner Jg7IGU(dct
begin ,Qp58u2V
set @OwnerName = @OldOwner + '.' + rtrim(@Name) nwz}&nR
exec sp_changeobjectowner @OwnerName, @NewOwner 1 }:k w
end hj-M
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-- select @name,@NewOwner,@OldOwner E;%{hAD{
FETCH NEXT FROM curObject INTO @Name, @Owner 0O[q6!&]
END #u#s'W
close curObject Nz2}Ma 2
deallocate curObject ZV&=B%J bs
GO %!WQ;(
10、SQL SERVER中直接循环写入数据 wLW!_D,/R
declare @i int J9{B
set @i=1 p_[k^@$
while @i<30 a-hF/~84S:
begin ym-212wl
insert into test (userid) values(@i) ]Qj65]
set @i=@i+1 ~fr1O`8
end jLZ+HYyG9
小记存储过程中经常用到的本周,本月,本年函数 U,)+wZJ
Dateadd(wk,datediff(wk,0,getdate()),-1) Dtn|$g,
Dateadd(wk,datediff(wk,0,getdate()),6) +&JF|#FQ`
Dateadd(mm,datediff(mm,0,getdate()),0) puDy&T
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) rGx1>xd(k
Dateadd(yy,datediff(yy,0,getdate()),0) +-5CM0*&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) No j6Ina
上面的SQL代码只是一个时间段 bw+~5pqM
Dateadd(wk,datediff(wk,0,getdate()),-1) GX(p7ZgB2
Dateadd(wk,datediff(wk,0,getdate()),6) F+9|D
就是表示本周时间段. &7}-Xvc
下面的SQL的条件部分,就是查询时间段在本周范围内的: HAP9XC(F]
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) O75ioO0
而在存储过程中 D*heYh
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) BoFJ8Ukq|
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 7HFw*;