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。 wK7w[Xt
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一、基础 ;tVd+[8
1、说明:创建数据库 u"(NN9s
CREATE DATABASE database-name )^ZC'[93
2、说明:删除数据库 3<+ZA-2
drop database dbname >
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3、说明:备份sql server v]EZYEXFL)
--- 创建 备份数据的 device @vyEN.K%mm
USE master 3N-
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Uq_lT,
--- 开始 备份 2t_g\Q
BACKUP DATABASE pubs TO testBack XPqGv=CN
4、说明:创建新表 \wsVO"/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )W
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根据已有的表创建新表: ,cS#
A:create table tab_new like tab_old (使用旧表创建新表) TP {\V>*Yz
B:create table tab_new as select col1,col2... from tab_old definition only fX 1%I
5、说明:删除新表 K mH))LIv
drop table tabname 8..|-<w
6、说明:增加一个列 f3G:J<cL
Alter table tabname add column col type A03io8D6
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。 X>yDj]*4P
7、说明:添加主键: Alter table tabname add primary key(col) ZCj1Cz]"l<
说明:删除主键: Alter table tabname drop primary key(col) F"k`PF*b
8、说明:创建索引:create [unique] index idxname on tabname(col....) bAH<h
删除索引:drop index idxname ^*`#+*C
注:索引是不可更改的,想更改必须删除重新建。 A :KZyd"Z
9、说明:创建视图:create view viewname as select statement /eH37H
删除视图:drop view viewname ]
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10、说明:几个简单的基本的sql语句 qQ^CSn98J
选择:select * from table1 where 范围 BRM `/s
插入:insert into table1(field1,field2) values(value1,value2) `r-Jy{!y4
删除:delete from table1 where 范围 EC8Z. Uu
更新:update table1 set field1=value1 where 范围 8g!79q\c4
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! x$` lQ%
排序:select * from table1 order by field1,field2 [desc] [(_,\:L${
总数:select count as totalcount from table1
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求和:select sum(field1) as sumvalue from table1 I50LysM
平均:select avg(field1) as avgvalue from table1 dR.?Kv(,E
最大:select max(field1) as maxvalue from table1 fXWE4^jU
最小:select min(field1) as minvalue from table1 L-E?1qhP>
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11、说明:几个高级查询运算词 G\MeJSt*
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A: UNION 运算符 B *O/>=_
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。 }JST(d&
B: EXCEPT 运算符 kI!@J6
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。 oY0b8=[
C: INTERSECT 运算符 n:wAxU
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。 @OT$* Qh
注:使用运算词的几个查询结果行必须是一致的。 #tHYCSr]
12、说明:使用外连接 =dHdq D
A、left outer join: dtY8>klI
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 8g)$%Fy+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 CQ. C{
B:right outer join: M0lJyzJ
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。 h_P[B
C:full outer join: qS! Lt3+
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。 NY<qoV
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二、提升 uwI"V|g%a&
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) mD% qDKI
法一:select * into b from a where 1<>1 :TP4f
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法二:select top 0 * into b from a m%})H"5
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) qvo!nr7
insert into b(a, b, c) select d,e,f from b; %pOxt<
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)
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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 G$'UK
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. D`[@7$t
4、说明:子查询(表名1:a 表名2:b) n(# yGzq
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) ltkARc3
5、说明:显示文章、提交人和最后回复时间 H1q,w|O9j
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ewn\'RLZ"@
6、说明:外连接查询(表名1:a 表名2:b) 9eHqOmz
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c jf1GYwuW*
7、说明:在线视图查询(表名1:a ) P(I%9
select * from (SELECT a,b,c FROM a) T where t.a > 1; g.!k>_g`
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 0Cf'\2
select * from table1 where time between time1 and time2 ^Tj{}<yT
select a,b,c, from table1 where a not between 数值1 and 数值2 H)Me!^@[D
9、说明:in 的使用方法 zBq&/?
select * from table1 where a [not] in ('值1','值2','值4','值6') J9tV|0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 NQuqM`LSQ
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ct=K.m@E%X
11、说明:四表联查问题: J,:;\Xhl
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 ..... !PeSnO
12、说明:日程安排提前五分钟提醒 GSSmlJ`
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 N$t<&5+
13、说明:一条sql 语句搞定数据库分页 P"}"q ![
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 m*B4a9f
14、说明:前10条记录 B0Z>di:
select top 10 * form table1 where 范围 \v=@'
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) t OJyj49^a
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) = vF!
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 hg<[@Q%$o
(select a from tableA ) except (select a from tableB) except (select a from tableC) P{%Urv{U
17、说明:随机取出10条数据 F/LMk8RgR
select top 10 * from tablename order by newid() -~JYfj@
18、说明:随机选择记录 Vh=U/{Rp1
select newid() 6!itr"
19、说明:删除重复记录 Ja&S_'P[
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) *]R5bj.!o
20、说明:列出数据库里所有的表名 Z;1r=p#s
select name from sysobjects where type='U' W?wt$'
21、说明:列出表里的所有的 \I}EWI
select name from syscolumns where id=object_id('TableName') _4nm h0q4
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ='+I dn#5
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 8Ed axeDq
显示结果: Nr*X1lJ6
type vender pcs P {n*X
电脑 A 1 L[nDjQn"
电脑 A 1 OR
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光盘 B 2 R:Ih#2R
光盘 A 2 2T?Y
手机 B 3 t54?<-
手机 C 3 I][&*V1
23、说明:初始化表table1 Np$&8v+en
TRUNCATE TABLE table1 8*#$3e
24、说明:选择从10到15的记录 T2rBH]5
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc PrfG
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三、技巧 %*Mr ^=
1、1=1,1=2的使用,在SQL语句组合时用的较多 E6O!e<ze^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 6L\]Ee
如: lEHXh2
if @strWhere !='' 9v-Y*\!w.
begin ,:'JJZg@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere @Y.r ,q
end H-u
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else |sFd5X
begin kF,ME5%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 6`7bk35B
end Pn.DeoHme
我们可以直接写成 {5c?_U
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere m`q&[:
2、收缩数据库 -}!mi V
--重建索引 :wg=H
DBCC REINDEX ~&MDfpl
DBCC INDEXDEFRAG olxxs(
--收缩数据和日志 A! HJ
DBCC SHRINKDB
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DBCC SHRINKFILE %t!S 7UD
3、压缩数据库 Lr8|S
dbcc shrinkdatabase(dbname) >35w"a7S
4、转移数据库给新用户以已存在用户权限 , u%V%
exec sp_change_users_login 'update_one','newname','oldname' ]W2#8:i
go kRX?o'U~C
5、检查备份集 &s?uMWR
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?r8hl.Z>
6、修复数据库 0pEM0M
ALTER DATABASE [dvbbs] SET SINGLE_USER Lq;iR
GO <BZC5b6
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK L1(-xNUo_i
GO A9K$:mL<2
ALTER DATABASE [dvbbs] SET MULTI_USER F?H=2mzKbz
GO Pz:,de~5Qm
7、日志清除 h:?qd
SET NOCOUNT ON CqZHs
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DECLARE @LogicalFileName sysname, ^QJJ2 jZ
@MaxMinutes INT, GQA\JYw|oY
@NewSize INT |?g-8":H8P
USE tablename -- 要操作的数据库名 M
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 NqOX);'L0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. } -;)G~h/"
@NewSize = 1 -- 你想设定的日志文件的大小(M) ]Z6? m
-- Setup / initialize oxL<\4)WJ
DECLARE @OriginalSize int +YW;63"o
SELECT @OriginalSize = size .n YlYY'
FROM sysfiles to&,d`k=-
WHERE name = @LogicalFileName s>L.V2!$0
SELECT 'Original Size of ' + db_name() + ' LOG is ' + CyYr5 Dz
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Kn@#5MC
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 5<v1v&
FROM sysfiles F4z#u2~TC
WHERE name = @LogicalFileName MO7R3PP
CREATE TABLE DummyTrans (g X8iKl
(DummyColumn char (8000) not null) T7.SjR6X>
DECLARE @Counter INT, |D/a}Av>B
@StartTime DATETIME, ~:f..|JM
@TruncLog VARCHAR(255) Lkx~>U
SELECT @StartTime = GETDATE(), nC%qdzT
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' mS![J69(
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ?jlz:Z4
EXEC (@TruncLog) >jIn&s!}
-- Wrap the log if necessary. {dpDQP +!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired <Ohi+a%6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _ ~\} fY
AND (@OriginalSize * 8 /1024) > @NewSize QOg >|"KL
BEGIN -- Outer loop. -XV+F@`Md
SELECT @Counter = 0 Q]N&^ E
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) z
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BEGIN -- update -/{FGbpR;
INSERT DummyTrans VALUES ('Fill Log') YJ"D"QD
DELETE DummyTrans *w*>\ZhOm
SELECT @Counter = @Counter + 1 ?-mOAHW0q
END 'gs P9
EXEC (@TruncLog) s*yl&El/
END p2t04p!
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ^&1O:G*"
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 7(.Z8AO
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' M;ADL|
FROM sysfiles x@rQ7K>
WHERE name = @LogicalFileName eeCG#NFY5
DROP TABLE DummyTrans vZTXvdF
SET NOCOUNT OFF *{fs{gFw9
8、说明:更改某个表 =r ^_D=
exec sp_changeobjectowner 'tablename','dbo' ;]=w6'dP!
9、存储更改全部表 @g5y_G{SP
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %wOkp`1-
@OldOwner as NVARCHAR(128), Nv36#^Z
@NewOwner as NVARCHAR(128) <Jhd%O
AS G|1.qHP[F
DECLARE @Name as NVARCHAR(128) /^nIOAeE
DECLARE @Owner as NVARCHAR(128) |3,WiK='
DECLARE @OwnerName as NVARCHAR(128) C){Q;`M-<
DECLARE curObject CURSOR FOR jj]\]6@+P
select 'Name' = name, .UL2(0
'Owner' = user_name(uid) A[;deHg=
from sysobjects 8ex;g^e
where user_name(uid)=@OldOwner /CsP@f_Gw
order by name ;i6~iLY
OPEN curObject H"AL@=
FETCH NEXT FROM curObject INTO @Name, @Owner /ie&uWy
WHILE(@@FETCH_STATUS=0) (=7"zECq#
BEGIN nI6ompTX
if @Owner=@OldOwner 8Zsaq1S
begin \~%+)a%%
set @OwnerName = @OldOwner + '.' + rtrim(@Name) zs#-E_^%M
exec sp_changeobjectowner @OwnerName, @NewOwner !9/`PcNIpy
end
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-- select @name,@NewOwner,@OldOwner `Fr ,,Q81\
FETCH NEXT FROM curObject INTO @Name, @Owner 2\1+M)
END .i4aM;Qy
close curObject 8~C}0H
deallocate curObject m1%rm-M
GO
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10、SQL SERVER中直接循环写入数据 hp'oiR;~w
declare @i int SQcic]Ep
set @i=1 Y%"$v0D
while @i<30 (X"5x]7]
begin >EJ{ *
insert into test (userid) values(@i) KZ7B2
set @i=@i+1 )Ac,F6w
end -@w,tbc$
小记存储过程中经常用到的本周,本月,本年函数 ~+4lmslR
Dateadd(wk,datediff(wk,0,getdate()),-1) GE!nf6>Km
Dateadd(wk,datediff(wk,0,getdate()),6) :;eOhZ=_
Dateadd(mm,datediff(mm,0,getdate()),0) EZB0qZIp
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) /=6_2t#vA
Dateadd(yy,datediff(yy,0,getdate()),0) [l5jPL}6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2T2<I/")O
上面的SQL代码只是一个时间段 .euAN8L
Dateadd(wk,datediff(wk,0,getdate()),-1) nb/q!8
Dateadd(wk,datediff(wk,0,getdate()),6) -1Li&K7
就是表示本周时间段. j
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下面的SQL的条件部分,就是查询时间段在本周范围内的: fL2P6N@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) <h/q^| tZ{
而在存储过程中 fW2NYQP$:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) WMtFXkf6"
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Ro2V-6/