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。 XRi37|p
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一、基础 fDAT#nlyp
1、说明:创建数据库 C)ic;!$Qhb
CREATE DATABASE database-name V6_~"pRR=
2、说明:删除数据库 L&&AK`Ur3l
drop database dbname w`[`:H_z
3、说明:备份sql server 5Q,j+
--- 创建 备份数据的 device Dlz1"|SF
USE master }j{Z
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' gUme({h&|
--- 开始 备份 oiQ:&$y
BACKUP DATABASE pubs TO testBack ^(KDtc
4、说明:创建新表 t? Q
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) &U\//
根据已有的表创建新表: qUk-BG8^
A:create table tab_new like tab_old (使用旧表创建新表) 7V&ly{</
B:create table tab_new as select col1,col2... from tab_old definition only luJNdA:t&
5、说明:删除新表 De<i
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drop table tabname G)&!f)6
6、说明:增加一个列 _po5j;"_O
Alter table tabname add column col type rLA^ &P:
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。 TjOK8
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7、说明:添加主键: Alter table tabname add primary key(col) rq:sy=;
说明:删除主键: Alter table tabname drop primary key(col) s` =&l
8、说明:创建索引:create [unique] index idxname on tabname(col....) !{vZvy"
删除索引:drop index idxname Pb<6-Jc[
注:索引是不可更改的,想更改必须删除重新建。 n>xuef
9、说明:创建视图:create view viewname as select statement iB + _+A
删除视图:drop view viewname @>+`1C
10、说明:几个简单的基本的sql语句 -`5L;cxwk4
选择:select * from table1 where 范围 XI"IEwB
插入:insert into table1(field1,field2) values(value1,value2) L$^)QxH7
删除:delete from table1 where 范围 >J{e_C2ZS
更新:update table1 set field1=value1 where 范围 hHgH'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! rVwW%&
排序:select * from table1 order by field1,field2 [desc] *vT Abk$
总数:select count as totalcount from table1 tv5N
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求和:select sum(field1) as sumvalue from table1 |Rz}bsrZ
平均:select avg(field1) as avgvalue from table1 #I#_gjJkx
最大:select max(field1) as maxvalue from table1 kb!W|l"PN
最小:select min(field1) as minvalue from table1 %DKC/%
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11、说明:几个高级查询运算词 XpPcQIM*
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A: UNION 运算符 Yn>FSq^Wp-
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。 M-(,*6Q
B: EXCEPT 运算符 1jd.tup
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。 %yK- Q,'O
C: INTERSECT 运算符 _)6r@fZ.p
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。 r(<91~Ww
注:使用运算词的几个查询结果行必须是一致的。 NRI[|
12、说明:使用外连接 eh,_g.
A、left outer join: ;rl61d}NH#
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。 3&R1C>JS ]
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 fONycXM]
B:right outer join: ?gCP"~
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。 57EL&V%j
C:full outer join: X$eR RSW
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 uM9Gj@_
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二、提升 Rb0{W]opt+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 1";s#Jq
法一:select * into b from a where 1<>1 ]'Gz~Z%>F
法二:select top 0 * into b from a K{XE|g
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Mtn{63cK
insert into b(a, b, c) select d,e,f from b; uJa.]J~L=
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) <&HHo>rl
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ]+>Kl>@
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 0CI\Yd=
4、说明:子查询(表名1:a 表名2:b) %K0Wm#)
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) jVna;o)
5、说明:显示文章、提交人和最后回复时间 7?8+h
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Ym2Ac>I4
6、说明:外连接查询(表名1:a 表名2:b) )Jh:~9L%='
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c bL|$\'S
7、说明:在线视图查询(表名1:a ) pxCQ=0k
select * from (SELECT a,b,c FROM a) T where t.a > 1; &Y3ZGRT
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 0Y8Cz /$
select * from table1 where time between time1 and time2 67U6`9d
select a,b,c, from table1 where a not between 数值1 and 数值2 &&C'\,ZK5
9、说明:in 的使用方法 [S0wwWU |0
select * from table1 where a [not] in ('值1','值2','值4','值6') P.djR)YI
10、说明:两张关联表,删除主表中已经在副表中没有的信息 JO~62='J
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) azG"Mt|7Z
11、说明:四表联查问题: b]*OGp4]5
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 ..... }\1IsK~P
12、说明:日程安排提前五分钟提醒 &td
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 N w/it*f
13、说明:一条sql 语句搞定数据库分页 -}RGz_LO/
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 "om[S :ai
14、说明:前10条记录 8&CQx*
select top 10 * form table1 where 范围 xEufbFAN?
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.) b`;Cm)@X!)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) GyfKSj;
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 O"wo&5b_
(select a from tableA ) except (select a from tableB) except (select a from tableC) HIda%D
17、说明:随机取出10条数据 ?>My&yB
select top 10 * from tablename order by newid() AmrVxn4
18、说明:随机选择记录 H% FP!03
select newid() 9{Igw"9ck
19、说明:删除重复记录 3il$V78|
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) FJFO0Hb6
20、说明:列出数据库里所有的表名 bd2QQ1[1vh
select name from sysobjects where type='U' !Oi':OQG
21、说明:列出表里的所有的 2rHQ7
select name from syscolumns where id=object_id('TableName') p+-IvU
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。 K1p. {
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 :mt<]Oy3
显示结果: i"mQ
type vender pcs sAnb
电脑 A 1 }(K1=cEaL
电脑 A 1 &d]@$4u$;
光盘 B 2 wJu9.
光盘 A 2 z}Um$'. =
手机 B 3 A.(e=;0bu
手机 C 3 p[}~Z|(
23、说明:初始化表table1 HE0m#
TRUNCATE TABLE table1 I/u>Gt
24、说明:选择从10到15的记录 B?4Iu)bCxI
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5>hXqNjP2
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三、技巧 TY?O$d2b3
1、1=1,1=2的使用,在SQL语句组合时用的较多 m=a^t
"where 1=1" 是表示选择全部 "where 1=2"全部不选, a'O-0]g,
如: g*!1S
if @strWhere !='' Bve',.xH
begin eV"Uv3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere dV
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end .UvDew/Y
else >u]9(o7I
begin ((M>To_l
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' fh`}~ aQ
end MjbgAH-
我们可以直接写成 h)s&Nqg1B
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere M^G9t*I
2、收缩数据库 9U3 .=J
--重建索引 <@c@`K
DBCC REINDEX .R^ R|<x
DBCC INDEXDEFRAG iu2O/l#r
--收缩数据和日志 Z:diM$Z?7
DBCC SHRINKDB d+"F(R9
DBCC SHRINKFILE cv. j
3、压缩数据库 h-U]?De5\
dbcc shrinkdatabase(dbname) qKE +,g'
4、转移数据库给新用户以已存在用户权限 yh'*eli
exec sp_change_users_login 'update_one','newname','oldname' -J0I2D
go S|?P#.=GX
5、检查备份集 g'2}Y5m$`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' @.,'A[D!K
6、修复数据库 GGUwS
ALTER DATABASE [dvbbs] SET SINGLE_USER +jO#?J
GO bGK-?BE5+A
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ^ Z3y
GO &PX!'%X68h
ALTER DATABASE [dvbbs] SET MULTI_USER . HAFKB;
GO :_Iz(
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7、日志清除 u/xP$
SET NOCOUNT ON 2iC BF-,
DECLARE @LogicalFileName sysname, T
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@MaxMinutes INT, ?QtM|e
@NewSize INT ]C{N4Ni^Z
USE tablename -- 要操作的数据库名 .N7&Jy
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7^1K4%IPl
@MaxMinutes = 10, -- Limit on time allowed to wrap log. t0Inf
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@NewSize = 1 -- 你想设定的日志文件的大小(M) |nU%H=Rs/
-- Setup / initialize t{`uN
DECLARE @OriginalSize int Jgy6 !qUn_
SELECT @OriginalSize = size B] Koi1B
FROM sysfiles %.8(R
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WHERE name = @LogicalFileName t| B<F t^
SELECT 'Original Size of ' + db_name() + ' LOG is ' + "V5_B^Gzb]
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + m8INgzVTC
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' - %?>1n
FROM sysfiles C#P>3"
WHERE name = @LogicalFileName bAUYJPRpy
CREATE TABLE DummyTrans ,^jQBD4={
(DummyColumn char (8000) not null) ,V''?@
DECLARE @Counter INT, c?6(mU\x
@StartTime DATETIME, +~7[T/v+n
@TruncLog VARCHAR(255) [8vqw(2Tm(
SELECT @StartTime = GETDATE(), `%~f5<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' dP"cm0
DBCC SHRINKFILE (@LogicalFileName, @NewSize) /=QsZ,~xo
EXEC (@TruncLog) Wxgs66
-- Wrap the log if necessary. =@nW;PUZ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired X5= Ki
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ]qx!51S
AND (@OriginalSize * 8 /1024) > @NewSize X?] Mzcu
BEGIN -- Outer loop.
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SELECT @Counter = 0 C;ME"4,(
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Hi U/fi`
BEGIN -- update #v4^,$k>
INSERT DummyTrans VALUES ('Fill Log') fT<3~Z>m
DELETE DummyTrans To-$)GQ@W
SELECT @Counter = @Counter + 1 #IeG/t(
END \*pS4vy5x
EXEC (@TruncLog) p*JP='p
END @P[%6 d
SELECT 'Final Size of ' + db_name() + ' LOG is ' + mS.!lkV
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ds@K%f(.?w
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 7,Q7`}gBf
FROM sysfiles ,t|_Nc
WHERE name = @LogicalFileName MfA%Xep
DROP TABLE DummyTrans j`_Z`eG
SET NOCOUNT OFF e.(RhajB
8、说明:更改某个表 iztgk/(+G
exec sp_changeobjectowner 'tablename','dbo' 89W8cJ$yW
9、存储更改全部表 >n1UK5QD
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch "o@R}_4]q
@OldOwner as NVARCHAR(128), -*2b/=$u
@NewOwner as NVARCHAR(128) \2Kl]G(w%y
AS aw7pr464
DECLARE @Name as NVARCHAR(128) xX~m Fz0C
DECLARE @Owner as NVARCHAR(128) 5oOs.(m|*C
DECLARE @OwnerName as NVARCHAR(128) [7[$P.MS{
DECLARE curObject CURSOR FOR ]ed7Q3lq
select 'Name' = name, \\ZhM
'Owner' = user_name(uid) r%LG>c`^
from sysobjects [p)2!]y
where user_name(uid)=@OldOwner MW0CqMi]T
order by name 7e{w,.ny!
OPEN curObject 1M[|9nWUC
FETCH NEXT FROM curObject INTO @Name, @Owner UaHN*@
WHILE(@@FETCH_STATUS=0) fUJe{C<H
BEGIN 5!6}g<z&L
if @Owner=@OldOwner f%REN3=5K
begin GB}X
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ke'OT>8
exec sp_changeobjectowner @OwnerName, @NewOwner }-vP~I
end ^SS9BQ*m
-- select @name,@NewOwner,@OldOwner ^(:n a6C
FETCH NEXT FROM curObject INTO @Name, @Owner j>~@vq
END (e<p^TJ]
close curObject `2'*E\
deallocate curObject
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GO + Cq&~<B
10、SQL SERVER中直接循环写入数据 /|<0,oz oJ
declare @i int r?`7i'
set @i=1 jQ(%LYX$
while @i<30 [VouG{
begin 3W3d $
insert into test (userid) values(@i) H$&P=\8n
set @i=@i+1 By<~h/uJ
end =.9tRq
小记存储过程中经常用到的本周,本月,本年函数 ^.Q/iXgh
Dateadd(wk,datediff(wk,0,getdate()),-1) ?!bWUVC)_
Dateadd(wk,datediff(wk,0,getdate()),6) ~$bQ;`,L
Dateadd(mm,datediff(mm,0,getdate()),0) S7CD#Y[s
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 24Htr/lPCT
Dateadd(yy,datediff(yy,0,getdate()),0) =[Tf9uQY
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <"S/M]9
上面的SQL代码只是一个时间段 JZ-M<rcC
Dateadd(wk,datediff(wk,0,getdate()),-1) b~K-mjJI
Dateadd(wk,datediff(wk,0,getdate()),6) u_$Spbc]/
就是表示本周时间段. >k
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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: mPi{:
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ML
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而在存储过程中 d UiS0Qs}
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) fy!,cK};
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) jLBwPI_g