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。 Ix~rBD9
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一、基础 Iv u'0vF
1、说明:创建数据库 Wq?vAnLbk
CREATE DATABASE database-name <oSx'_dc
2、说明:删除数据库 Jyp7+M]
drop database dbname p[;@9!t
3、说明:备份sql server 8~O0P=
--- 创建 备份数据的 device B3I0H6O
USE master >LB*5
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' z$Qy<_l
--- 开始 备份 \3hFb,/4k
BACKUP DATABASE pubs TO testBack y(Em+YTD
4、说明:创建新表 6=*n$l#}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) xhB-gG=
根据已有的表创建新表: _,f7D/dq
A:create table tab_new like tab_old (使用旧表创建新表) nB}eJD|
B:create table tab_new as select col1,col2... from tab_old definition only 7&(h_}Z
5、说明:删除新表 tq L2' (=
drop table tabname ,pUB[w\
6、说明:增加一个列 }*vE/W
Alter table tabname add column col type ']Z%6_WF
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。 kPO+M~+n
7、说明:添加主键: Alter table tabname add primary key(col) w8#ji 1gX
说明:删除主键: Alter table tabname drop primary key(col) i8#:y`ai
8、说明:创建索引:create [unique] index idxname on tabname(col....) n1b^o~agwC
删除索引:drop index idxname Ql,WKoj*
注:索引是不可更改的,想更改必须删除重新建。 <@y(ikp>
9、说明:创建视图:create view viewname as select statement `X B$t?xi
删除视图:drop view viewname /4upw`35]
10、说明:几个简单的基本的sql语句 c @KNyBy2
选择:select * from table1 where 范围 >GmO8dK
插入:insert into table1(field1,field2) values(value1,value2) 6.a|w}C`
删除:delete from table1 where 范围 <y#@v G
更新:update table1 set field1=value1 where 范围 N37CAbw0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! U?
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排序:select * from table1 order by field1,field2 [desc] #E#@6ZomT
总数:select count as totalcount from table1 (^]3l%Ed
求和:select sum(field1) as sumvalue from table1 /PG%Y]l0b
平均:select avg(field1) as avgvalue from table1 ^KV:.up6
最大:select max(field1) as maxvalue from table1 lXD=uRCI
最小:select min(field1) as minvalue from table1 .sb0|3&
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11、说明:几个高级查询运算词 shiw;.vR{B
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A: UNION 运算符 ziv+*Qn_b4
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ?ea5k*#a
B: EXCEPT 运算符 Ml)<4@
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 :z\||f
C: INTERSECT 运算符 kZfj"+p_S
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 eu//Q'W
注:使用运算词的几个查询结果行必须是一致的。 *g4Uo{
12、说明:使用外连接 ![eipOX
A、left outer join: HaR x(p0
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ~RV9'v4
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {5+ 39=(
B:right outer join: (R9"0WeF
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 2<d'!cm
C:full outer join: nk;+L
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 j|b$b,rF\
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二、提升 wp@6RJ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) kc2
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法一:select * into b from a where 1<>1 jV<5GWq
法二:select top 0 * into b from a +^.xLTX`$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Wxi;Tq9C@_
insert into b(a, b, c) select d,e,f from b; 8[a N5M]
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) v7D0E[)~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 $-\%%n0>6
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ${97G#
4、说明:子查询(表名1:a 表名2:b) <Rz[G+0S=
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) X@7:FzU9
5、说明:显示文章、提交人和最后回复时间 .73sY5hdTN
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b V h5\'Sn
6、说明:外连接查询(表名1:a 表名2:b) gA 19f
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c x$pz(Q&v
7、说明:在线视图查询(表名1:a ) _6]tbni?v
select * from (SELECT a,b,c FROM a) T where t.a > 1; Mv:\T%]
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:z'
select * from table1 where time between time1 and time2 8rNf4]5@X(
select a,b,c, from table1 where a not between 数值1 and 数值2 -.Zy(
9、说明:in 的使用方法 y-Lm^GW4
select * from table1 where a [not] in ('值1','值2','值4','值6') J?jxD/9Yb
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Iomx"y]9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) oMNBK/X_
11、说明:四表联查问题: {<cgeH
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 ..... KSUhB
12、说明:日程安排提前五分钟提醒
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 +KIBbXF7
13、说明:一条sql 语句搞定数据库分页 _9S"rH[
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 -@~4: o
14、说明:前10条记录 ,<TJh[TzC6
select top 10 * form table1 where 范围 #.LI`nYA
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.) Ol;"}3*Z*
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) m,F4N$
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 59V8cO+qH
(select a from tableA ) except (select a from tableB) except (select a from tableC) U?EXPi6 1Z
17、说明:随机取出10条数据 Bo0T}P~
select top 10 * from tablename order by newid() V]Uc@7S/
18、说明:随机选择记录 9rM#w"E?<
select newid() _#
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19、说明:删除重复记录 q{!ft9|K\d
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ?` 2z8uD/
20、说明:列出数据库里所有的表名 7bR[.|T
select name from sysobjects where type='U' i3>_E <"9
21、说明:列出表里的所有的 >=3oe.$)
select name from syscolumns where id=object_id('TableName') w ;:{
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 *QoQ$alHH
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 ~Yre(8+M
显示结果: \3x+Z!
type vender pcs cxIAI=JK
电脑 A 1 z\K-KD{Ad
电脑 A 1 WqHp23
光盘 B 2 1([?EfC
光盘 A 2 }#nd&ND
手机 B 3 .8wF>
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手机 C 3 S=$ \S9
23、说明:初始化表table1 %)e&"mq!|
TRUNCATE TABLE table1 hF1Lj=x
24、说明:选择从10到15的记录 ]v_u2f'
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (62Sc]
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三、技巧 A|m0.'/
1、1=1,1=2的使用,在SQL语句组合时用的较多 QjTs$#eMW
"where 1=1" 是表示选择全部 "where 1=2"全部不选, {Ut,xi
如: V} h)e3X
if @strWhere !='' $wk(4W8E
begin Lv #}Gm
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Zb+n\sv4
end IYhn*
else ^[q/w<_j~
begin m4R:KjN*
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' $-39O3
end ^+Vf*YY
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我们可以直接写成 /^`do3a}
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere LXRIo2ynuw
2、收缩数据库 o3le[6C/8=
--重建索引 A=np?wc
DBCC REINDEX 6L-3cxqf\
DBCC INDEXDEFRAG o\nFSGkn
--收缩数据和日志 -I~\
DBCC SHRINKDB `L3{y/U'
DBCC SHRINKFILE \{o<-S;h
3、压缩数据库 1Q$/L+uJ5
dbcc shrinkdatabase(dbname) ^fbzlu?G4-
4、转移数据库给新用户以已存在用户权限 6Zv-kG
exec sp_change_users_login 'update_one','newname','oldname' e`?o`@vO,
go = @ 1{LF;
5、检查备份集 hE +M|#o
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' =r~ExW}+
6、修复数据库 x,
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ALTER DATABASE [dvbbs] SET SINGLE_USER |doG}C
GO eX'V#K#C
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK xBE}/F$45
GO SYgkYR
ALTER DATABASE [dvbbs] SET MULTI_USER I8\R7s3
GO Z5"5Ge-M
7、日志清除 O
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SET NOCOUNT ON S]gV! Q4%
DECLARE @LogicalFileName sysname, iVb7>d9}
@MaxMinutes INT, Wyb+K)Tg
@NewSize INT es\Fn#?O
USE tablename -- 要操作的数据库名 I@(3~ Ab
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 26=G%F6
@MaxMinutes = 10, -- Limit on time allowed to wrap log. w[u>*I
@NewSize = 1 -- 你想设定的日志文件的大小(M) f/sLQdK,
-- Setup / initialize H4W!@"e
DECLARE @OriginalSize int (:RYd6i
SELECT @OriginalSize = size sLc,Dx"+
FROM sysfiles QGnUPiD^
WHERE name = @LogicalFileName O*>`md?MH
SELECT 'Original Size of ' + db_name() + ' LOG is ' + F1%^,;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4!-/m7%eF
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' w$jSlgUHy)
FROM sysfiles q( %)^C
WHERE name = @LogicalFileName $,nidK!"
CREATE TABLE DummyTrans Ru$%gh>v
(DummyColumn char (8000) not null) /'bX}H(dq
DECLARE @Counter INT, {@[#0gPH
@StartTime DATETIME, @={
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@TruncLog VARCHAR(255) pwA~?$B1
SELECT @StartTime = GETDATE(), =TA8]7S~U
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 7LiyA<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) a._>?rVy
EXEC (@TruncLog) vJ>o9:(6
-- Wrap the log if necessary. ((6?b5[
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {v2[x W
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Ys<z%
AND (@OriginalSize * 8 /1024) > @NewSize q<cxmo0S
BEGIN -- Outer loop. >oapw5~5
SELECT @Counter = 0 <Kk?BRxi
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Xc<Hm
BEGIN -- update hwSxdT6
INSERT DummyTrans VALUES ('Fill Log') ?2K~']\S
DELETE DummyTrans l=<},_]{
SELECT @Counter = @Counter + 1 u&e?3qKX(
END w3"%d~/[x
EXEC (@TruncLog) n9V8A[QJ
END 5e^z]j1Yv
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 5a:YzQ4
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + <'~6L#>,<
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' S>d7q
FROM sysfiles %<MI]D
WHERE name = @LogicalFileName !j9(%,PR
DROP TABLE DummyTrans J$S*QCo
SET NOCOUNT OFF Qa"4^s
8、说明:更改某个表 "J2v8c
exec sp_changeobjectowner 'tablename','dbo' &
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9、存储更改全部表 }&^1")2t
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch pbGv\SF
@OldOwner as NVARCHAR(128), tQ)l4Y 8
@NewOwner as NVARCHAR(128) >KJE *X@s
AS A"IaFXB
DECLARE @Name as NVARCHAR(128) vg5fMH9ZZ
DECLARE @Owner as NVARCHAR(128) &Zo+F]3d
DECLARE @OwnerName as NVARCHAR(128) D 75;Y;E
DECLARE curObject CURSOR FOR \OkJX_7
select 'Name' = name, E4<#6q
'Owner' = user_name(uid) g+-^6UG
from sysobjects e+y%M
where user_name(uid)=@OldOwner w^[:wzF0
order by name '_" S/X+v
OPEN curObject <WL] (-9I:
FETCH NEXT FROM curObject INTO @Name, @Owner ?8q4texf[
WHILE(@@FETCH_STATUS=0) 1|$J>
BEGIN )00jRuF
if @Owner=@OldOwner w=thaF.
begin s^/2sjoL
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5oo6d4[
exec sp_changeobjectowner @OwnerName, @NewOwner [2ri=lf,
end ;VbB]aUg
-- select @name,@NewOwner,@OldOwner }*7Gq
FETCH NEXT FROM curObject INTO @Name, @Owner 3w+ +F@(
END Gg%pU+'T
close curObject od*#)
deallocate curObject >P-'C^:V=
GO 9!6u Yf+
10、SQL SERVER中直接循环写入数据 |wuN`;gc"
declare @i int <4N E)!#
set @i=1 Q;kl-upn~8
while @i<30 a,e;(/#\7
begin U :8cz=#
insert into test (userid) values(@i) uIR
set @i=@i+1 u\)q.`
end }+F@A`Bm&
小记存储过程中经常用到的本周,本月,本年函数 5Trc#i<\
Dateadd(wk,datediff(wk,0,getdate()),-1) Iz&<rL;s
Dateadd(wk,datediff(wk,0,getdate()),6) '<AE%i,
Dateadd(mm,datediff(mm,0,getdate()),0) (mx}6A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) !ozHS_
Dateadd(yy,datediff(yy,0,getdate()),0) E>F6!qYm
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) peVzF'F
上面的SQL代码只是一个时间段 #/)U0IR)
Dateadd(wk,datediff(wk,0,getdate()),-1) r<'B\.#tp>
Dateadd(wk,datediff(wk,0,getdate()),6) %< Jj[F
就是表示本周时间段. %/R[cj8
下面的SQL的条件部分,就是查询时间段在本周范围内的: /.(F\2+A
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) FmQiy+.|
而在存储过程中 QG09=GQ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) T )bMHk
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ~jJe|zg>