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。 )?!vJb"
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一、基础 L@)b%Q@a
1、说明:创建数据库 E}xz7u
CREATE DATABASE database-name 3I'M6WA
2、说明:删除数据库 l9M#]*{
drop database dbname f28gE7Y\a
3、说明:备份sql server f?/|;Zo4
--- 创建 备份数据的 device [z
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USE master n@G:e-m{A
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \e`6=Q%
--- 开始 备份 FBR$,j;Y
BACKUP DATABASE pubs TO testBack 1<XiD3H;
4、说明:创建新表 kA7~Yu5|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) c%q}"Y0oh
根据已有的表创建新表: R=][>\7]}
A:create table tab_new like tab_old (使用旧表创建新表) Qh)|FQ[s$r
B:create table tab_new as select col1,col2... from tab_old definition only !L&=?CX
5、说明:删除新表 Zp/qs
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drop table tabname |#DC.Ga!
6、说明:增加一个列 O!#L#u53
Alter table tabname add column col type .Ws iOJU
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。 *6 I =oE
7、说明:添加主键: Alter table tabname add primary key(col) ,Hik (22
说明:删除主键: Alter table tabname drop primary key(col) IeRl6r%:
8、说明:创建索引:create [unique] index idxname on tabname(col....) ZTQ$Ol+{q
删除索引:drop index idxname NYSj^k;^(z
注:索引是不可更改的,想更改必须删除重新建。 -IpV'%nX;
9、说明:创建视图:create view viewname as select statement IgzCh
删除视图:drop view viewname ^
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10、说明:几个简单的基本的sql语句 DBj;P|L_
选择:select * from table1 where 范围 _ 4~ng#M*
插入:insert into table1(field1,field2) values(value1,value2) gp#bQ
删除:delete from table1 where 范围 4f@havFIJ
更新:update table1 set field1=value1 where 范围 J]n7| L
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! u\Nw:Uu i
排序:select * from table1 order by field1,field2 [desc] "'Q" (S
总数:select count as totalcount from table1 kr/1Dsr4
求和:select sum(field1) as sumvalue from table1 {u(}ED#p
平均:select avg(field1) as avgvalue from table1 qB+:#Yrx/
最大:select max(field1) as maxvalue from table1 ,xAM[h&
最小:select min(field1) as minvalue from table1 +t7c&td\
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11、说明:几个高级查询运算词 FT|/WZR
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A: UNION 运算符 ~aauW?
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 +WV_`Rx#
B: EXCEPT 运算符 dVj'
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Y\z^\k
C: INTERSECT 运算符 ;qMnO_E
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ZbZAx:L
注:使用运算词的几个查询结果行必须是一致的。 (/9.+V_
12、说明:使用外连接 ;qT!fuN;
A、left outer join: g|GvJ)VX
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ^| FVc48{
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Ru
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B:right outer join: wB1|r{
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 K-"HcHuF
C:full outer join: t[f9Z
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 s0`|G|.}
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二、提升 Ul$X%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) wH(vX<W-E
法一:select * into b from a where 1<>1 FkJ>]k
法二:select top 0 * into b from a T
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =7J|KoKK
insert into b(a, b, c) select d,e,f from b; DiYJlD&
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) )bIK0h
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Q#J>vwi=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. [o[v"e\w
4、说明:子查询(表名1:a 表名2:b) .J1Hg
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) ) v[Knp'
5、说明:显示文章、提交人和最后回复时间 u':0"5}
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 11@2 ;vw
6、说明:外连接查询(表名1:a 表名2:b) bWC~Hv
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .
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7、说明:在线视图查询(表名1:a ) Z_^Kl76D
select * from (SELECT a,b,c FROM a) T where t.a > 1; p^zEfLTU
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 Z@.ol Y
select * from table1 where time between time1 and time2 Z#TgFQ3u
select a,b,c, from table1 where a not between 数值1 and 数值2 P^_d$
9、说明:in 的使用方法 pRxlvVt
select * from table1 where a [not] in ('值1','值2','值4','值6') =:n[{/O=
10、说明:两张关联表,删除主表中已经在副表中没有的信息 8O.:3%D~
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ev;5?9\E
11、说明:四表联查问题: kq1M<lk
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 ..... u>Axq3F
12、说明:日程安排提前五分钟提醒 uZ2v;]\Y6
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 a9@l8{)RX
13、说明:一条sql 语句搞定数据库分页 #Zavdkw=d
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 e/HX,sf_g
14、说明:前10条记录 ;aRWJG
select top 10 * form table1 where 范围 W-]yKSob
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.) t1RwB23
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 1O3<%T#LOZ
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 *l?%
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(select a from tableA ) except (select a from tableB) except (select a from tableC) l~6 SR
17、说明:随机取出10条数据 _9O }d
select top 10 * from tablename order by newid() o%~K4 M".
18、说明:随机选择记录 n xh/&%
select newid() &A5[C{x
19、说明:删除重复记录 y1"^S
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) #u=O 5%.
20、说明:列出数据库里所有的表名 .&yWHdQC:
select name from sysobjects where type='U' wmcp`8w.
21、说明:列出表里的所有的 tv=FFfQ
select name from syscolumns where id=object_id('TableName') qf&a<[p~
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。 1\608~ZH
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 5$"[gdt)T
显示结果: {8bY7NH|
type vender pcs Bzy=@]`
电脑 A 1 OB
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电脑 A 1 $5"-s]
光盘 B 2 @
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光盘 A 2 'a{5}8+8
手机 B 3 em9]WSfZ@`
手机 C 3 8^"|-~#<
23、说明:初始化表table1 qyBK\WqaP
TRUNCATE TABLE table1 )J6b:W
24、说明:选择从10到15的记录 fi4/@tV?$L
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc %/4_|@<'
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三、技巧 {FmFu$z+[
1、1=1,1=2的使用,在SQL语句组合时用的较多 u/:Sf*;?
"where 1=1" 是表示选择全部 "where 1=2"全部不选, "vRqtEBO@
如: gMK3o8B/
if @strWhere !='' dv9Pb5i
begin nu9k{owB T
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere e4W];7_K!
end 4!s k3Cw{
else e"H+sM26-
begin {)[g
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Umwg
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end ; o@`l$O
我们可以直接写成 H=BR
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere j83Y'VJJC
2、收缩数据库 ~V-
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--重建索引 }]GK@nn7
DBCC REINDEX 5sCky)N
DBCC INDEXDEFRAG b!HFv;^N
--收缩数据和日志 ;WAu]C|
DBCC SHRINKDB _ktSTzH0
DBCC SHRINKFILE ?d#(ian
3、压缩数据库 ?'#;Y"RT
dbcc shrinkdatabase(dbname) (X7yNIPfA
4、转移数据库给新用户以已存在用户权限 HY| SLk/E
exec sp_change_users_login 'update_one','newname','oldname' ,Y5 4(>>%
go #<>E+r+
5、检查备份集 zr9Pm6Rl
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &E'>+6
6、修复数据库 RkV3_c
ALTER DATABASE [dvbbs] SET SINGLE_USER Sm_:SF!<D6
GO ^A<.s_
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK n *0F
GO o%>nu
ALTER DATABASE [dvbbs] SET MULTI_USER nMoF;AdKm
GO Oc+L^}elJ
7、日志清除 U"kK]Stk<
SET NOCOUNT ON td$6:)
DECLARE @LogicalFileName sysname, xENA:j?kF
@MaxMinutes INT, 44{:UhJkx
@NewSize INT 3K:Xxkk
USE tablename -- 要操作的数据库名 XBt0Ez
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 knZd}?I*
@MaxMinutes = 10, -- Limit on time allowed to wrap log. `/Jr8J_
@NewSize = 1 -- 你想设定的日志文件的大小(M) "lzg@=$|)
-- Setup / initialize 5e8-?w%e
DECLARE @OriginalSize int g\nL
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SELECT @OriginalSize = size A"ph!* i{
FROM sysfiles kRa$jD^?
WHERE name = @LogicalFileName jtpN o~O
SELECT 'Original Size of ' + db_name() + ' LOG is ' + &'2l_b
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z:gsguX
FROM sysfiles AG%es0D[H
WHERE name = @LogicalFileName {cHTg04
CREATE TABLE DummyTrans K{h]./%
(DummyColumn char (8000) not null) { 3P!b|V>
DECLARE @Counter INT, o@~gg*
@StartTime DATETIME, }4`YdN
@TruncLog VARCHAR(255) xT(.#9
SELECT @StartTime = GETDATE(), GuDD7~qxY
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' }33Au-%*
DBCC SHRINKFILE (@LogicalFileName, @NewSize) .%h_W\M<l
EXEC (@TruncLog) U]&%EqLS
-- Wrap the log if necessary. -*j;
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired BeCr){,3
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) t$D[,$G9
AND (@OriginalSize * 8 /1024) > @NewSize ]>!_OCe&
BEGIN -- Outer loop. |8+rUFkU8
SELECT @Counter = 0 L| qY
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ArKrsI#H-
BEGIN -- update j*\MUR=
INSERT DummyTrans VALUES ('Fill Log') p)]^>-L
DELETE DummyTrans
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SELECT @Counter = @Counter + 1 @d9*<>@:
END C>-"*Lt
EXEC (@TruncLog) &G,v*5N8$K
END L7'n<$F
SELECT 'Final Size of ' + db_name() + ' LOG is ' + KiHAm|,
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 7cQw?C
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ht!:e>z&4
FROM sysfiles goWt!,&f
WHERE name = @LogicalFileName uB! P>v6
DROP TABLE DummyTrans R
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SET NOCOUNT OFF V:np cKpu
8、说明:更改某个表 iKO~#9OF
exec sp_changeobjectowner 'tablename','dbo' [qo*,CRz
9、存储更改全部表 Qd=/e pkm
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8[XNFFUZs
@OldOwner as NVARCHAR(128), TQfY%GKg(
@NewOwner as NVARCHAR(128) "K]4j]yU
AS @}}1xP4Sr
DECLARE @Name as NVARCHAR(128) ^U1+D^AJ
DECLARE @Owner as NVARCHAR(128) yrb%g~ELGn
DECLARE @OwnerName as NVARCHAR(128) I*t}gvUt9
DECLARE curObject CURSOR FOR _J`M>W)8
select 'Name' = name, '7%9Sqx
'Owner' = user_name(uid) ?q7Gs)B=^'
from sysobjects -O6o^Dk
where user_name(uid)=@OldOwner 8;bOw
order by name 4K,&Q/Vdd7
OPEN curObject SxyFFt
FETCH NEXT FROM curObject INTO @Name, @Owner %|||M=akk
WHILE(@@FETCH_STATUS=0) 7]
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BEGIN C_;6-Q%V
if @Owner=@OldOwner w%"q=V
begin Cq'r
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) lTNkm Q
exec sp_changeobjectowner @OwnerName, @NewOwner -UE-v
end |MGw$
-- select @name,@NewOwner,@OldOwner AS398L
FETCH NEXT FROM curObject INTO @Name, @Owner #6nA^K}
END IEj`:]d
close curObject $xwF;:)
deallocate curObject cwM0Z6
GO f5eX%FR
10、SQL SERVER中直接循环写入数据 zj}efv<e
declare @i int w}0PtzOe
set @i=1 Z!6G(zz:>
while @i<30 ~Y$1OA8
begin Il[WXt<S
insert into test (userid) values(@i) $NSYQF%aO
set @i=@i+1 O5"80z38[
end VzNH%
小记存储过程中经常用到的本周,本月,本年函数 r,\(Y@I
Dateadd(wk,datediff(wk,0,getdate()),-1) *+ayC{!
Dateadd(wk,datediff(wk,0,getdate()),6) nfR5W~%*:
Dateadd(mm,datediff(mm,0,getdate()),0) PI?[
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) pgarGaeq
Dateadd(yy,datediff(yy,0,getdate()),0) 9)`wd&!
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) P^r8JhDJ
上面的SQL代码只是一个时间段 q1j[eru
Dateadd(wk,datediff(wk,0,getdate()),-1) "5FeP;
Dateadd(wk,datediff(wk,0,getdate()),6) 37DvI&
就是表示本周时间段. SJmri]4K
下面的SQL的条件部分,就是查询时间段在本周范围内的: 23m+"4t
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Obm\h*$
而在存储过程中 :>u{BG;=79
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) e!yt<[ph
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0Oq1ay^