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。 J@p[v3W
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一、基础 `<b 3e(A
1、说明:创建数据库 q`"gT;3S
CREATE DATABASE database-name qD7#q]
2、说明:删除数据库 `[VoW2CLH+
drop database dbname 3xp%o5K
3、说明:备份sql server 1ncY"S/VO
--- 创建 备份数据的 device % ]r@vjeyd
USE master xo7H^!_
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' d_1w
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--- 开始 备份 EoIP#Cnd1
BACKUP DATABASE pubs TO testBack ?9OiF-:n
4、说明:创建新表 0Evmq3,9
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {-7];e
根据已有的表创建新表: +>44'M^Z|(
A:create table tab_new like tab_old (使用旧表创建新表) T%
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B:create table tab_new as select col1,col2... from tab_old definition only @m1v B!
5、说明:删除新表 x AkM_<
drop table tabname R`!x<J
6、说明:增加一个列 ^r}^-
Alter table tabname add column col type ~ NKw}6
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。 2\CFt;fk
7、说明:添加主键: Alter table tabname add primary key(col) Z[ZqQ` 7N
说明:删除主键: Alter table tabname drop primary key(col) 8e[kE>tS._
8、说明:创建索引:create [unique] index idxname on tabname(col....) Do=*bZ;A
删除索引:drop index idxname #- f7hg*
注:索引是不可更改的,想更改必须删除重新建。 TPvS+_<oL{
9、说明:创建视图:create view viewname as select statement =HQH;c"
删除视图:drop view viewname aq oT
10、说明:几个简单的基本的sql语句 `5=0f}E
选择:select * from table1 where 范围 ZV,n-M =
插入:insert into table1(field1,field2) values(value1,value2) 7K
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删除:delete from table1 where 范围 t
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更新:update table1 set field1=value1 where 范围 %kKe"$)0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! &owBmpz
排序:select * from table1 order by field1,field2 [desc] _udH(NC
总数:select count as totalcount from table1 B&O931E7
求和:select sum(field1) as sumvalue from table1 m%qah>11
平均:select avg(field1) as avgvalue from table1 ^z"90-V^
最大:select max(field1) as maxvalue from table1 ,l.O @
最小:select min(field1) as minvalue from table1 ]+
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11、说明:几个高级查询运算词 o'D{ql
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A: UNION 运算符 Pi40w+/
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 [JO'ta
B: EXCEPT 运算符 {h7*a=
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 600-e;p
C: INTERSECT 运算符 BN|+2D+S
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 #T99p+O
注:使用运算词的几个查询结果行必须是一致的。 I}kx;!*b
12、说明:使用外连接 k8GcHqNHx
A、left outer join: :@`Ll;G
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 z<m,Xj4w
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c f:KKOLm
B:right outer join: =xS(Er`r
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 n^UrHHOL
C:full outer join: iKv{)5
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 05TZ
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二、提升 <fJoHS
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6HCP1`gg
法一:select * into b from a where 1<>1 q\x*@KQgM
法二:select top 0 * into b from a "qu%$L
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) : N> 5{
insert into b(a, b, c) select d,e,f from b; V+nqQ~pJ&
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) :05>~bn>pC
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 k10dkBoEX
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. pV=X
4、说明:子查询(表名1:a 表名2:b) :eo2t>zF-<
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) Om\?<aul
5、说明:显示文章、提交人和最后回复时间 0N;Pb(%7UU
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "e&S*8QhM
6、说明:外连接查询(表名1:a 表名2:b) k =ru)
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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 z%}^9
7、说明:在线视图查询(表名1:a ) (fUXJ$
select * from (SELECT a,b,c FROM a) T where t.a > 1; cZe,l1$
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 S"!nM]2L
select * from table1 where time between time1 and time2 #W @6@Mv
select a,b,c, from table1 where a not between 数值1 and 数值2 erdWGUfQOe
9、说明:in 的使用方法 r\F`xtR(
select * from table1 where a [not] in ('值1','值2','值4','值6') x&8HBF'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 S=U*is
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) jI_TN5
11、说明:四表联查问题: d?$FAy'o5
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 ..... _Su?
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12、说明:日程安排提前五分钟提醒 [@eNb^R
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 zbOEF
13、说明:一条sql 语句搞定数据库分页 qq]ZkT}
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 JY(_}AAu
14、说明:前10条记录 $*Njvr7
select top 10 * form table1 where 范围 &DYHkG
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.) OHdCt
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) J)6RXt*!
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 5%rD7/7N
(select a from tableA ) except (select a from tableB) except (select a from tableC) Eyxw.,rB/
17、说明:随机取出10条数据 a<k x95
select top 10 * from tablename order by newid() .8<bz4
18、说明:随机选择记录 5)wz `OS
select newid() w6F4o;<PR
19、说明:删除重复记录 q=M!YWz
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) S#/[>Cb
20、说明:列出数据库里所有的表名 ^cz#PNB
select name from sysobjects where type='U' 'gxSHqeI2
21、说明:列出表里的所有的 5%mc|
select name from syscolumns where id=object_id('TableName') <Qe30_<K
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。 c_s=>z
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 r{pTMcDS
显示结果: C&^"]-t
type vender pcs L%# #U'e3
电脑 A 1 vj]-p=
电脑 A 1 v/
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光盘 B 2 <S:SIaf0
光盘 A 2 'JsP9>)
手机 B 3 :EJ+#
手机 C 3 Psij*%I4
23、说明:初始化表table1 h\Ck""&
TRUNCATE TABLE table1 ?lKFcm
24、说明:选择从10到15的记录 U;<07
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 3WZ]9v{k
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三、技巧 <Td4 o&JR
1、1=1,1=2的使用,在SQL语句组合时用的较多 Wf^6:
"where 1=1" 是表示选择全部 "where 1=2"全部不选, $vnshU8/v
如: cT'D2Yeq
if @strWhere !='' FaYDa
begin GS_'&Yj
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 3Kc
end d/vF^v*o0X
else =B@owx
begin rK;F]ei
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +@ga
end eGwrSF#a)
我们可以直接写成 9^h0D}#@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9YS &RBJu
2、收缩数据库 &x
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--重建索引 _5 Zhv-7
DBCC REINDEX p}$VBl$'
DBCC INDEXDEFRAG BUqe~E|I
--收缩数据和日志 ~mP#V
DBCC SHRINKDB \R#]}g0!
DBCC SHRINKFILE bnt>j0E
3、压缩数据库 1K.i>]}>
dbcc shrinkdatabase(dbname) Q%o:*(x[O
4、转移数据库给新用户以已存在用户权限 *~~ >?
exec sp_change_users_login 'update_one','newname','oldname' u )cc
go g)c<\%
5、检查备份集 uO8z .
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' DUUQz:?{J
6、修复数据库 >0z(+}]3z
ALTER DATABASE [dvbbs] SET SINGLE_USER e~w-v"'
GO 7SO i9JU_
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO FJDx80J
ALTER DATABASE [dvbbs] SET MULTI_USER o{5es
GO th]1>
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7、日志清除 ys`"-o[*
SET NOCOUNT ON \ws<W7
DECLARE @LogicalFileName sysname, zRSIJ!A~
@MaxMinutes INT, %g1:yx
@NewSize INT 'yd<<BM`
USE tablename -- 要操作的数据库名 D|lp3\`%
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 |giV<Sj
@MaxMinutes = 10, -- Limit on time allowed to wrap log. $a|C/s+}7>
@NewSize = 1 -- 你想设定的日志文件的大小(M) LxaR1E(Cc'
-- Setup / initialize qOAK`{b
DECLARE @OriginalSize int Qxr&zT7f
SELECT @OriginalSize = size #\U;,r
FROM sysfiles w7aC=B/{?i
WHERE name = @LogicalFileName <2@V$$Qg.~
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <3i2(k
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ;/T=ctIs
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' k`ulDQu
FROM sysfiles u
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WHERE name = @LogicalFileName %s<7M@]f
CREATE TABLE DummyTrans b3]QH
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(DummyColumn char (8000) not null) 8L]em&871
DECLARE @Counter INT, >Z@^R7_W
@StartTime DATETIME, F)rU*i7
@TruncLog VARCHAR(255) Nr 5h%<`I
SELECT @StartTime = GETDATE(), 3.,O7 k7y
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' S?TyC";!
DBCC SHRINKFILE (@LogicalFileName, @NewSize) (|H1zO
EXEC (@TruncLog) Qz6Ry\u
-- Wrap the log if necessary. Ni"n_Yun
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Dg(882#_
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =w&JDj
AND (@OriginalSize * 8 /1024) > @NewSize J;"66ue(d
BEGIN -- Outer loop. aF2vw{wT}
SELECT @Counter = 0 T v2d?y
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &cy@Be}|T
BEGIN -- update 0RmQfD>
INSERT DummyTrans VALUES ('Fill Log') t:|knZq
DELETE DummyTrans P(B:tg
SELECT @Counter = @Counter + 1 KtH-QQDluj
END nHiE$Y
EXEC (@TruncLog) $}kT)+K
END Z#w@ /!"}T
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :ZrE/3_S
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + !##OQ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' *UM=EQaYk
FROM sysfiles +*/XfPlr|
WHERE name = @LogicalFileName 5y3V duE
DROP TABLE DummyTrans p1^k4G
SET NOCOUNT OFF X@`kuWIUw
8、说明:更改某个表 ZmM/YPy
exec sp_changeobjectowner 'tablename','dbo' 5`] ;[M9
9、存储更改全部表 E2J.t`H
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch !58j xh
@OldOwner as NVARCHAR(128), qRy<W
@NewOwner as NVARCHAR(128) ~@g7b`t=la
AS yKSvg5lLy
DECLARE @Name as NVARCHAR(128) 3!]S8Y*LQP
DECLARE @Owner as NVARCHAR(128) s az<NT
DECLARE @OwnerName as NVARCHAR(128) DdO$&/`)YP
DECLARE curObject CURSOR FOR Npu#.)G
select 'Name' = name, nSUQ Eho<
'Owner' = user_name(uid) 5~ho1Ud
from sysobjects p) #7K
where user_name(uid)=@OldOwner )q#1C]7m*
order by name cO}`PD$i
OPEN curObject gzdR|IBa
FETCH NEXT FROM curObject INTO @Name, @Owner yc ize2>q
WHILE(@@FETCH_STATUS=0) Z*,Nt6;e
BEGIN +"8AmN4
if @Owner=@OldOwner ;Oh abbj*
begin jpg$5jZ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) sJA` A
exec sp_changeobjectowner @OwnerName, @NewOwner E"8cB]`|8
end H<6TN^
-- select @name,@NewOwner,@OldOwner )<Cf,R
FETCH NEXT FROM curObject INTO @Name, @Owner xz9xt
END yMz%s=rh
close curObject f;";P
deallocate curObject 2|Of$oMc
GO 3eOwy~
10、SQL SERVER中直接循环写入数据 UvwO/A\Gv
declare @i int hRKAs
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set @i=1 ZcT%H*Ib]9
while @i<30 jV:Krk6T<
begin c-1Hxd YD
insert into test (userid) values(@i) ~CTe5PX c
set @i=@i+1 zB,Vi-)vH
end
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小记存储过程中经常用到的本周,本月,本年函数 8 cN[t.S
Dateadd(wk,datediff(wk,0,getdate()),-1) 4rpx
Dateadd(wk,datediff(wk,0,getdate()),6) kl(id8r
Dateadd(mm,datediff(mm,0,getdate()),0) btb$C
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) w0`aW6t#
Dateadd(yy,datediff(yy,0,getdate()),0) _T[7N|'O
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) a g=,oYn
上面的SQL代码只是一个时间段 G.ag$KF
Dateadd(wk,datediff(wk,0,getdate()),-1) 0[ (Z48
Dateadd(wk,datediff(wk,0,getdate()),6) (7v]bqfw
就是表示本周时间段. AHa%?wb
下面的SQL的条件部分,就是查询时间段在本周范围内的: lt:xN?--A?
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) u;-_%?
而在存储过程中 HfQZRDH
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) /HlLfW
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) &35 6