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。 F'Vl\qPt
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一、基础 kV<)>Gs
1、说明:创建数据库 2C&%UZim;P
CREATE DATABASE database-name d+)L\
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2、说明:删除数据库 |}Lgo"cTC
drop database dbname &1Iy9&y
3、说明:备份sql server B)NB6dCp
--- 创建 备份数据的 device (ytkq(
USE master I(S6DkU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' N#ObxOE6T"
--- 开始 备份 \mGM#E
BACKUP DATABASE pubs TO testBack Ji=iq=S7
4、说明:创建新表 r $2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) AXI:h"so
根据已有的表创建新表: J8'zvH&I
A:create table tab_new like tab_old (使用旧表创建新表) m@?e
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B:create table tab_new as select col1,col2... from tab_old definition only Z}f_\d'
5、说明:删除新表 S!cXc/H-R
drop table tabname 1i2O]e!
6、说明:增加一个列 jgIzB1H
Alter table tabname add column col type 3S?+G)qKo
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。 hdb4E|'A
7、说明:添加主键: Alter table tabname add primary key(col) ?^Ux+mVE
说明:删除主键: Alter table tabname drop primary key(col) U0T N8O}Z
8、说明:创建索引:create [unique] index idxname on tabname(col....) R:p,Hav<q
删除索引:drop index idxname g{(nt5|^l
注:索引是不可更改的,想更改必须删除重新建。 x~^nlnKVf
9、说明:创建视图:create view viewname as select statement WGK::?
删除视图:drop view viewname *RM'0[1F4
10、说明:几个简单的基本的sql语句 Uc2#so$9
选择:select * from table1 where 范围 Z;s-t\C
插入:insert into table1(field1,field2) values(value1,value2) g&wQ^
删除:delete from table1 where 范围 v,B\+q/
更新:update table1 set field1=value1 where 范围 _Y=yR2O
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! i|GC 'XD@
排序:select * from table1 order by field1,field2 [desc] ARo5 Ss{
总数:select count as totalcount from table1 q"oNB-bz
求和:select sum(field1) as sumvalue from table1 S#dS5OX
平均:select avg(field1) as avgvalue from table1 }IL@j A
最大:select max(field1) as maxvalue from table1 tT:yvU@a
最小:select min(field1) as minvalue from table1 U @|_5[nl
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11、说明:几个高级查询运算词 xcA:Q`c.{
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A: UNION 运算符 8E{>czF"
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。 PMcyQ2R->
B: EXCEPT 运算符 !C?z$5g
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 \9^@,kfP
C: INTERSECT 运算符 "N_?yA#(j
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 tAUMSr|?
注:使用运算词的几个查询结果行必须是一致的。 nc)`ISI
12、说明:使用外连接 H_^c K
A、left outer join: 7O#>N}|
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 W{d/m;<@N
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1\uS~RR
B:right outer join: <Vb{QOgc;
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 {{\HU0g>&
C:full outer join: Z%R^;8 !~
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Dl{Pd`D
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二、提升 %s>E@[s
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) /Z_QCj
法一:select * into b from a where 1<>1 KMZ`Wn=
法二:select top 0 * into b from a rf@81Ds
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) |*i-Q @
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insert into b(a, b, c) select d,e,f from b; WW=7QCi
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ?|\Lm3%J
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 h>?OWI
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. kTV D4Z=
4、说明:子查询(表名1:a 表名2:b) HFOp4
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) oLoa71Q}
5、说明:显示文章、提交人和最后回复时间 Z/x~:u_
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b bkTj
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6、说明:外连接查询(表名1:a 表名2:b) hkG<I';M?M
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c gN%R-e0
7、说明:在线视图查询(表名1:a ) `Ec+i
select * from (SELECT a,b,c FROM a) T where t.a > 1; MZ'HMYed
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 C'ZU .Y
select * from table1 where time between time1 and time2 {YFru6$
select a,b,c, from table1 where a not between 数值1 and 数值2 ||f4f3R'
9、说明:in 的使用方法 "2J;~
select * from table1 where a [not] in ('值1','值2','值4','值6') szHUHW~;J
10、说明:两张关联表,删除主表中已经在副表中没有的信息 4~4Hst#^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) F<[8!^l(z
11、说明:四表联查问题: n^K]R}S
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 ..... UpILr\3U
12、说明:日程安排提前五分钟提醒 Eh+lLtZ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 vq}V0-
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13、说明:一条sql 语句搞定数据库分页 J']W7!p
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 5>
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14、说明:前10条记录 E2MpMR
select top 10 * form table1 where 范围 aH_&=/-Tz
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.) Dp8(L ]6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) S(pfd2^
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 F+GQ l
(select a from tableA ) except (select a from tableB) except (select a from tableC) <S
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17、说明:随机取出10条数据 PLD!BD
select top 10 * from tablename order by newid() s6I]H
18、说明:随机选择记录 <OUApp H
select newid() >:=TS"}yS}
19、说明:删除重复记录 /.r($Sg^
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) B}W^s;h
20、说明:列出数据库里所有的表名 1K>4i. X
select name from sysobjects where type='U' Rjf|
21、说明:列出表里的所有的 ?k#%AM
select name from syscolumns where id=object_id('TableName') qF?S[Z;
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。 <qBPN{'a"
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 dZ*o H#B
显示结果: LBg#KQ@
type vender pcs )lbF'.i
电脑 A 1 pmC@ fB
电脑 A 1 @azS)4L
光盘 B 2 &m`
光盘 A 2 (<12&=WxE
手机 B 3 wZ^/-
手机 C 3 [kCn6\_<V
23、说明:初始化表table1 2rxdRg'YLQ
TRUNCATE TABLE table1 z,)Fvs4U.
24、说明:选择从10到15的记录 m#Cp.|>kP4
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc *;Vq0a!
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三、技巧 O1z>A
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, HN:{rAIfc
如: }~7>S5
if @strWhere !='' $hL0/T-m
begin m2;%|QE(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |:\h3M
end z, OMR`W
else &HWH
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begin zVIzrz0
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 7
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end }5~;jN=k
我们可以直接写成 X@arUs7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ,GK>|gNsb
2、收缩数据库 m>iuy:ti
--重建索引 ~Sh}\&3p
DBCC REINDEX '@$?A>.cj
DBCC INDEXDEFRAG \R~Lf+q
--收缩数据和日志 dgO2fI
DBCC SHRINKDB 5+U~ZW0|+
DBCC SHRINKFILE I0Vm^\8
3、压缩数据库 :7R\"@V4
dbcc shrinkdatabase(dbname) sIyLW
4、转移数据库给新用户以已存在用户权限 U}UIbJD*=
exec sp_change_users_login 'update_one','newname','oldname' +G?3j ,a\
go )T>a|.
5、检查备份集 3}"VUS0wh
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <Sz9: hg-
6、修复数据库 Ss8`;>
ALTER DATABASE [dvbbs] SET SINGLE_USER A3Su&0uaB
GO 9(m^^
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &?~> I[^~
GO -/h$Yb
ALTER DATABASE [dvbbs] SET MULTI_USER , 7}Ri
GO $lO\eQGxB
7、日志清除 }Iu 6]?|'
SET NOCOUNT ON 1Ao"DxZHy7
DECLARE @LogicalFileName sysname, "MyYu}AD
@MaxMinutes INT, o:?IT/>
@NewSize INT 7QQnvoP
USE tablename -- 要操作的数据库名 R8ZW1
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 pM>.z9
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >9|Q,/b0
@NewSize = 1 -- 你想设定的日志文件的大小(M) 3mx7[Q
-- Setup / initialize blLX ncyD
DECLARE @OriginalSize int ztu N0}'
SELECT @OriginalSize = size ;$W|FpR2
FROM sysfiles +ux,cx.U"
WHERE name = @LogicalFileName (j2]:BVu
SELECT 'Original Size of ' + db_name() + ' LOG is ' + z8gp<5=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + n.XT-X^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ?f a/}|T
FROM sysfiles towQoqv
WHERE name = @LogicalFileName Z!*Wn`d-k
CREATE TABLE DummyTrans W{k}ogI;
(DummyColumn char (8000) not null) %cBJ haR{(
DECLARE @Counter INT, -1fT2e
@StartTime DATETIME, ,\Cy'TSz
@TruncLog VARCHAR(255) 6n>+cX>E
SELECT @StartTime = GETDATE(), kg_TXB
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Z{%h6""
DBCC SHRINKFILE (@LogicalFileName, @NewSize) }APf^Ry
EXEC (@TruncLog) f}o`3v*z
-- Wrap the log if necessary. d=q2Or
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired eQMY3/#
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) W4Zi?@L>'
AND (@OriginalSize * 8 /1024) > @NewSize c: _l+CgeH
BEGIN -- Outer loop. ?:UDK?
SELECT @Counter = 0 vRm;H|[%S
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ."9v1kW
BEGIN -- update 2 &R-zG
INSERT DummyTrans VALUES ('Fill Log') ;hRo}
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DELETE DummyTrans [IiwpC
SELECT @Counter = @Counter + 1
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END *ozeoX'5D
EXEC (@TruncLog) ZVeY`o(uE
END la
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + C]{43
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + YrA#NTB_o
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' + -U7ogs
FROM sysfiles |',MgA
WHERE name = @LogicalFileName yY8q{\G
DROP TABLE DummyTrans =EFF2M`F
SET NOCOUNT OFF xqIt?v2c
8、说明:更改某个表 $l Y
exec sp_changeobjectowner 'tablename','dbo' Fz-Bd*uS
9、存储更改全部表 o ;.j_
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $n!saPpxS
@OldOwner as NVARCHAR(128), NCBS=L:
@NewOwner as NVARCHAR(128) `ez_
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AS k|1/gd5
DECLARE @Name as NVARCHAR(128) 1H%LUA
DECLARE @Owner as NVARCHAR(128) Ow<=K:^
DECLARE @OwnerName as NVARCHAR(128) $5:j" )$,
DECLARE curObject CURSOR FOR waldLb>7D
select 'Name' = name, k/cQJz
'Owner' = user_name(uid) ?PLf+S
from sysobjects Hcuvu[)T"
where user_name(uid)=@OldOwner `}"*i_0-5'
order by name ;ZB[g78%R%
OPEN curObject Q
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FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) e5C560
BEGIN }>>BKn
if @Owner=@OldOwner v-EcJj%
begin 1%t9ic
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Y@F@k(lOo
exec sp_changeobjectowner @OwnerName, @NewOwner mZ'`XAS ~;
end cV=h8F
-- select @name,@NewOwner,@OldOwner (m25ZhW
FETCH NEXT FROM curObject INTO @Name, @Owner Z_Hc":4i
END YrFB~z.V
close curObject F:1w%#6av
deallocate curObject ^ola5w D
GO k#&d`?X
10、SQL SERVER中直接循环写入数据 NO8)XJ3s
declare @i int SVo:%mX
set @i=1 z\{ y[3-
while @i<30 *#w+*ywVZH
begin C8%q?.nH=
insert into test (userid) values(@i) w>J|416
set @i=@i+1 GeD^-.^
end b+9M? k"
小记存储过程中经常用到的本周,本月,本年函数 ;i@,TU
Dateadd(wk,datediff(wk,0,getdate()),-1) +\2{{~_z
Dateadd(wk,datediff(wk,0,getdate()),6) cE$7CSR
Dateadd(mm,datediff(mm,0,getdate()),0) 9])dLL0
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) V)=!pT
Dateadd(yy,datediff(yy,0,getdate()),0) Z~CL|=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) s,)Z8H
上面的SQL代码只是一个时间段 9s7sn*aB#5
Dateadd(wk,datediff(wk,0,getdate()),-1) *shE-w;C
Dateadd(wk,datediff(wk,0,getdate()),6) xp.~i*!`
就是表示本周时间段. 3{O^q/R
下面的SQL的条件部分,就是查询时间段在本周范围内的: FIDV5Y/f
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) |9Q4VY'";
而在存储过程中 }vgeQh-G
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) uzr(gFd
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Q,S~+bD(z