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。 rO YD[+
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一、基础 ~Nf|,{[(5
1、说明:创建数据库
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CREATE DATABASE database-name )vpYVr-
2、说明:删除数据库 cd=K=P}p
drop database dbname rq Uk_|Xa
3、说明:备份sql server /0$405
--- 创建 备份数据的 device a*:GCGe
USE master %NTJih`
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' /k(wb4Hv
--- 开始 备份 u } +?'B)
BACKUP DATABASE pubs TO testBack FvO,* r9
4、说明:创建新表 Oi]B%Uxy=
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) fVVD}GM=
根据已有的表创建新表: P,xJVo\
A:create table tab_new like tab_old (使用旧表创建新表) =BJe}AV
B:create table tab_new as select col1,col2... from tab_old definition only mahNQ5 W*)
5、说明:删除新表 =+I-9=
drop table tabname <M}O&?N
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6、说明:增加一个列 @ &Od1X
Alter table tabname add column col type 2@@evQ
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。 P2|+7D:
7、说明:添加主键: Alter table tabname add primary key(col) uu"hu||0_
说明:删除主键: Alter table tabname drop primary key(col) k@h0 }%
8、说明:创建索引:create [unique] index idxname on tabname(col....) P=L@!F+s
删除索引:drop index idxname & JJ*?Dl
注:索引是不可更改的,想更改必须删除重新建。 O{Mn\M6
9、说明:创建视图:create view viewname as select statement :z *jl'L
删除视图:drop view viewname x9S9%JG :
10、说明:几个简单的基本的sql语句 ?;.=o?e9
选择:select * from table1 where 范围 @A<~bod
插入:insert into table1(field1,field2) values(value1,value2) JfK4|{@
删除:delete from table1 where 范围 SU6Aq?`@
更新:update table1 set field1=value1 where 范围 *OIBMx#qxn
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! I_ kA!^
排序:select * from table1 order by field1,field2 [desc] n3qRt
总数:select count as totalcount from table1 )CmHC3
求和:select sum(field1) as sumvalue from table1 Zb|a\z8 ?
平均:select avg(field1) as avgvalue from table1 Mn<s9ITS-
最大:select max(field1) as maxvalue from table1 @`8a3sL)
最小:select min(field1) as minvalue from table1 ?Zk;NL9
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11、说明:几个高级查询运算词 3 `mtc@*
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A: UNION 运算符 12_7UWZ"
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。 8G9( )UF.
B: EXCEPT 运算符 0
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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。 .+<Ka0
C: INTERSECT 运算符 eH[i<Z
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。 x5Fo?E
注:使用运算词的几个查询结果行必须是一致的。 zA:q/i
12、说明:使用外连接 jUgx
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A、left outer join: A wk1d
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。 ;sq xFF@
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 zK{}
B:right outer join: ?r5a*
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。 r.6?|
C:full outer join: ,?Zy4-
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。 53pT{2]zAi
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二、提升 x;-D}#
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) }UQ,B
法一:select * into b from a where 1<>1 @LDs$"f9=
法二:select top 0 * into b from a n2Mpo\2
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) IiE^HgM
insert into b(a, b, c) select d,e,f from b; ccp9nXv
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) Q9B!0G.-bs
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 V0&7MY *
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 01uj-!D$@
4、说明:子查询(表名1:a 表名2:b) &GvSgdttv
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) ~l{Qz0&
5、说明:显示文章、提交人和最后回复时间 W}}ZP];
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ! hEZV&y
6、说明:外连接查询(表名1:a 表名2:b) nZc6
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c m_BpY9c]5
7、说明:在线视图查询(表名1:a ) D ]
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select * from (SELECT a,b,c FROM a) T where t.a > 1; apgKC;
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 -1`}|t;
select * from table1 where time between time1 and time2 _#+l?\u
select a,b,c, from table1 where a not between 数值1 and 数值2 1uR@ZK
9、说明:in 的使用方法 q;IuV&B
select * from table1 where a [not] in ('值1','值2','值4','值6') C dPQhv)m
10、说明:两张关联表,删除主表中已经在副表中没有的信息 D%c^j9' 1
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) pSIXv%1J
11、说明:四表联查问题: Wa.!eAe}
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 ..... E|SmvIV-
12、说明:日程安排提前五分钟提醒 \Y!=O=za]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,:MUf]Ky
13、说明:一条sql 语句搞定数据库分页 NYs<`6P:Y
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 8>D*U0sNl
14、说明:前10条记录 B,%KvL&xMX
select top 10 * form table1 where 范围
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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.) 4^4T#f2=e
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) B4+c3M\$V
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 ua &uR7
(select a from tableA ) except (select a from tableB) except (select a from tableC) 1/qD5 *`Y
17、说明:随机取出10条数据 8 ph1xQ'
select top 10 * from tablename order by newid() jVN=_Y}\
18、说明:随机选择记录 d(R8^v/L
select newid() Fm6]mz%~u#
19、说明:删除重复记录 GK6CnSV8d
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) UX.rzYM&T
20、说明:列出数据库里所有的表名 )1R[X!KQ7
select name from sysobjects where type='U' Tyb'p9
21、说明:列出表里的所有的 0Q8iX)
select name from syscolumns where id=object_id('TableName') g}K/ba'
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。 $=^}J6
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type '&K' 0qG
显示结果:
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type vender pcs E?|NYu#I6
电脑 A 1 \u[5O@v#
电脑 A 1 !8W0XUqh+
光盘 B 2 X.,R%>O}`P
光盘 A 2 a|3+AWL%
手机 B 3 R\#5;W^
手机 C 3 3pL4Zhf
23、说明:初始化表table1 R[fQ$` M
TRUNCATE TABLE table1 c'Z)uquvP
24、说明:选择从10到15的记录 TL7qOA7^X
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 6"}F
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三、技巧 f;l}Z|dok6
1、1=1,1=2的使用,在SQL语句组合时用的较多 5nceOG8
"where 1=1" 是表示选择全部 "where 1=2"全部不选, U~@;2\
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如: >c5
if @strWhere !='' ^gpd '*b
begin qNrLM!Rj
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Fl{~#]
end xy$aFPH!-
else T?.l_"%%d
begin D+ jvF
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' :P+7ti@
end f4NN?"W)
我们可以直接写成 vS3Y9|-:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere XtBEVqrhi
2、收缩数据库 R"CF xo
--重建索引 `zl,|}u)
DBCC REINDEX g}a+%Obb
DBCC INDEXDEFRAG OPqhdqo
--收缩数据和日志 ]iFW>N*a
DBCC SHRINKDB D@[#7:rHL
DBCC SHRINKFILE -HuIz6
3、压缩数据库 HJpx,NU'
dbcc shrinkdatabase(dbname) ?6x&A t
4、转移数据库给新用户以已存在用户权限 yGC
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exec sp_change_users_login 'update_one','newname','oldname' }NdLd!
go |o(te
5、检查备份集 f.oY:3h:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' xUa9>=JU{
6、修复数据库 hjk]?MC
ALTER DATABASE [dvbbs] SET SINGLE_USER o:
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GO U-f8D
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?>vkY^/
GO O~x{p,s
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ALTER DATABASE [dvbbs] SET MULTI_USER ;<E?NBV^
GO ]rg-=Y k
7、日志清除 ymqn1ja1
SET NOCOUNT ON O<Ay`p5
DECLARE @LogicalFileName sysname, !/|B4Yv
@MaxMinutes INT, Ag2Q!cq
@NewSize INT H/8u?OC
USE tablename -- 要操作的数据库名 > #9
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 BrzTOkeyG
@MaxMinutes = 10, -- Limit on time allowed to wrap log. j/E(*Hv
@NewSize = 1 -- 你想设定的日志文件的大小(M) J\'f5)k
-- Setup / initialize bS55/M w
DECLARE @OriginalSize int ^U,C])n
SELECT @OriginalSize = size a_b+RMy
FROM sysfiles By}ZHK94I
WHERE name = @LogicalFileName ,,#6SR(n
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %P#|
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + a8k`Wog
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' {c drMP@""
FROM sysfiles K!E\v4
WHERE name = @LogicalFileName p_apVm\t_
CREATE TABLE DummyTrans f6Y-ss;'
(DummyColumn char (8000) not null) F%%mcmHD#
DECLARE @Counter INT, wZ`{ i
@StartTime DATETIME, Z7e"4wA
@TruncLog VARCHAR(255) AAB_Ytf
SELECT @StartTime = GETDATE(), ,MHF
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' o`'4EVw*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) I\j-
EXEC (@TruncLog) Zny9TP
-- Wrap the log if necessary. {%,4P_m
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired >^<;;8Xh
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) i-dosY`81
AND (@OriginalSize * 8 /1024) > @NewSize YX3NZW2i
BEGIN -- Outer loop. BuC\Bd^0
SELECT @Counter = 0 ?"?AH/E D
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 'C:i5?zh(q
BEGIN -- update Rx.5;2m
INSERT DummyTrans VALUES ('Fill Log') h_\W7xt
DELETE DummyTrans 7W&XcF
SELECT @Counter = @Counter + 1 )RWukr+
END UKB/>:R
EXEC (@TruncLog) +9<:z\B|
END 9uX15a
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]A l)>
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |B^Picu
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ke/4l?zs
FROM sysfiles eU]I !pI<
WHERE name = @LogicalFileName F)/4#[
DROP TABLE DummyTrans FS('*w&bP
SET NOCOUNT OFF <5ULu(b&$
8、说明:更改某个表 7v.O Lp
exec sp_changeobjectowner 'tablename','dbo' evVxzU&
9、存储更改全部表 8S[bt@v
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch u`!Dp$P
@OldOwner as NVARCHAR(128), ~=otdJ
@NewOwner as NVARCHAR(128) #D>:'ezm
AS FZ8Qj8
DECLARE @Name as NVARCHAR(128) F6h IG G
DECLARE @Owner as NVARCHAR(128) [w+1<ou;j
DECLARE @OwnerName as NVARCHAR(128) u{l4O1k/c
DECLARE curObject CURSOR FOR UCTc$3
select 'Name' = name, 1$m{)Io2(
'Owner' = user_name(uid) 2)
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from sysobjects UvqnNA
where user_name(uid)=@OldOwner Zl]@;*u
order by name E2S#REB4
OPEN curObject <l+hcYam
FETCH NEXT FROM curObject INTO @Name, @Owner cVmF'g
WHILE(@@FETCH_STATUS=0) I0^oaccM
BEGIN 2%H_%Zu9
if @Owner=@OldOwner jOK!k
begin sY]pszjT
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [~n|R Oo
exec sp_changeobjectowner @OwnerName, @NewOwner Sj8fo^K50
end aan(69=jz
-- select @name,@NewOwner,@OldOwner p}X *HJq$
FETCH NEXT FROM curObject INTO @Name, @Owner 5,Co(K
END *Rc?rMF !
close curObject ,bB}lU)
deallocate curObject plNw>rFa
GO YelF)Na
10、SQL SERVER中直接循环写入数据 {?3i^Q=V
declare @i int l#p?lBm1
set @i=1 <v\x<ul6
while @i<30 rQPO+
begin t+0/$
insert into test (userid) values(@i) s)sT\crP@
set @i=@i+1 [DtMT6F3
end Z 2$S'}F
小记存储过程中经常用到的本周,本月,本年函数 IiX2O(*ZE
Dateadd(wk,datediff(wk,0,getdate()),-1) |]Y6*uEX<
Dateadd(wk,datediff(wk,0,getdate()),6) @?0))@kPc3
Dateadd(mm,datediff(mm,0,getdate()),0) RE]*fRe7#
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) GW.Y=S
Dateadd(yy,datediff(yy,0,getdate()),0) ?]TtUoY=)F
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) r -uu`=,
上面的SQL代码只是一个时间段 D<*)^^
Dateadd(wk,datediff(wk,0,getdate()),-1) Q7mikg=1-
Dateadd(wk,datediff(wk,0,getdate()),6) ZA'0q
就是表示本周时间段. -KqMSf&9
下面的SQL的条件部分,就是查询时间段在本周范围内的: 'loko#6
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) /c7jL4oD
而在存储过程中 (^<skx>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) =#&+w[4?&.
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) N)KN!!