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。 Cp=DdmR
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一、基础 <x@brXA
1、说明:创建数据库 / =&HunaxI
CREATE DATABASE database-name Q
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2、说明:删除数据库 f{MXH&d 1\
drop database dbname ,<s'/8Ik
3、说明:备份sql server [t/7hx"2t
--- 创建 备份数据的 device AeR3wua
USE master %Ez=
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Q$Qs$
--- 开始 备份 'D(| NYY
BACKUP DATABASE pubs TO testBack H+y(W5|2/X
4、说明:创建新表 `wz@l:e
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) kaf4GME]
根据已有的表创建新表: xU+c?OLi
A:create table tab_new like tab_old (使用旧表创建新表) <|9s {z
B:create table tab_new as select col1,col2... from tab_old definition only `6;%HbP$W+
5、说明:删除新表 :"5'l>la
drop table tabname |LA@guN
6、说明:增加一个列 KR4X&d6
Alter table tabname add column col type B|U*2|e
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 k"X<gA
7、说明:添加主键: Alter table tabname add primary key(col) T {Q]
说明:删除主键: Alter table tabname drop primary key(col) - ` F#MN
8、说明:创建索引:create [unique] index idxname on tabname(col....) Y1? wf.
删除索引:drop index idxname NF+^
注:索引是不可更改的,想更改必须删除重新建。 It>8XKS
9、说明:创建视图:create view viewname as select statement F33&A<(,
删除视图:drop view viewname FJJ+*3(
10、说明:几个简单的基本的sql语句 _tDSG]
选择:select * from table1 where 范围 a<-NB9o~v
插入:insert into table1(field1,field2) values(value1,value2) 3p`*'j 2R
删除:delete from table1 where 范围 7qj<|US
更新:update table1 set field1=value1 where 范围 21i ?$ uU
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! cnJ(Fv_F$
排序:select * from table1 order by field1,field2 [desc] &?C%
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总数:select count as totalcount from table1 s<,[xkMB
求和:select sum(field1) as sumvalue from table1 H:byCFN-
平均:select avg(field1) as avgvalue from table1 tmEF7e`(o
最大:select max(field1) as maxvalue from table1 &U/7D!^X
最小:select min(field1) as minvalue from table1 F;$z[z
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11、说明:几个高级查询运算词 t;X
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A: UNION 运算符 -DD2
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。 /NRdBN
B: EXCEPT 运算符 L-Qc[L
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。 K. [2uhB)
C: INTERSECT 运算符 Xm,w.|dx
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。 1KwUp0%&
注:使用运算词的几个查询结果行必须是一致的。 iV<4#aBg
12、说明:使用外连接 )fSO|4
A、left outer join: S%J $.ge
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。 =_~bSEqyRI
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 :uwB)G
B:right outer join: sk*AlSlM
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。 &Luq}^u
C:full outer join: n<RvL^T=
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。 m/}(dT;
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二、提升 @BCws)
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~1e?9D
法一:select * into b from a where 1<>1 _Q&O#f
法二:select top 0 * into b from a T^FeahA7;
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) peW4J<,
insert into b(a, b, c) select d,e,f from b; >a;0<Ui&Q
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) qy@v,a
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 UC&f
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. D|m]]B
4、说明:子查询(表名1:a 表名2:b) 4#D=+70'
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) 'u"r^o?
5、说明:显示文章、提交人和最后回复时间 +M@p)pyu
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b MP"Pqt
6、说明:外连接查询(表名1:a 表名2:b) hH Kd+QpI
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c `s[77V>
7、说明:在线视图查询(表名1:a ) =e\E{K'f@
select * from (SELECT a,b,c FROM a) T where t.a > 1; &oi*]:<FNe
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 !<`}mE!:
select * from table1 where time between time1 and time2 l6o?(!:!%
select a,b,c, from table1 where a not between 数值1 and 数值2 ['1JNUX
9、说明:in 的使用方法 7-Bttv{
select * from table1 where a [not] in ('值1','值2','值4','值6') <zUU`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 %&EDh2w>
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) )X-~+X91S
11、说明:四表联查问题: Iu(j"b#
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 ..... t<sy7e='
12、说明:日程安排提前五分钟提醒 N=4`jy =
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 QN!.~>
13、说明:一条sql 语句搞定数据库分页 1 /@lZ
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 }~/u%vI@M5
14、说明:前10条记录 Wk3R6
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select top 10 * form table1 where 范围 MZ9{*y[z
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.) z +NxO!y
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) oEfy{54
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 @|A
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(select a from tableA ) except (select a from tableB) except (select a from tableC) s^O>PEX&<I
17、说明:随机取出10条数据 E<=h6Ha
select top 10 * from tablename order by newid() C8^=7HEB
18、说明:随机选择记录 `{1`>5
select newid() (jQ]<q%P
19、说明:删除重复记录 tzl`|UwF
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) #s"|8#
20、说明:列出数据库里所有的表名 AH?T}t2
select name from sysobjects where type='U' T2Duz,
21、说明:列出表里的所有的 5Z
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select name from syscolumns where id=object_id('TableName') uLr9*nxd
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。 <\0+*`">g
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
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显示结果: X0G
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type vender pcs fK-tvP0}*
电脑 A 1 "v%|&@
电脑 A 1 R
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光盘 B 2 XLG6f(B= F
光盘 A 2 {~cG'S Y%
手机 B 3 z'iAj
手机 C 3 -s]
23、说明:初始化表table1 JQ9JWu%a
TRUNCATE TABLE table1 ;;6e
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24、说明:选择从10到15的记录 ,Oqd4NS
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc /K+GM8rtE
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三、技巧 E05RqnqBn0
1、1=1,1=2的使用,在SQL语句组合时用的较多 iEe<+Eyns
"where 1=1" 是表示选择全部 "where 1=2"全部不选, -wA^ao
如: G5;N#^myJ
if @strWhere !='' f[S$Gu4-
begin
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ry99R|/d1
end pUTC~|j%:
else V%kZ-P*
begin {'(1c)q>
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 0iy-FV;J
end kqyVUfX$3
我们可以直接写成 )Fa6'M
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere C3m](%?
2、收缩数据库 A4kYEA
--重建索引 ez2rCpA
DBCC REINDEX K/^70;/!.
DBCC INDEXDEFRAG d5b \kR r
--收缩数据和日志 _PI w""ssr
DBCC SHRINKDB I $5*Puy#
DBCC SHRINKFILE IUK!b2!`
3、压缩数据库 +y}4^3Vx^
dbcc shrinkdatabase(dbname) 1m$< %t.>
4、转移数据库给新用户以已存在用户权限 C`)n\?:Sth
exec sp_change_users_login 'update_one','newname','oldname' !21#NCw
go {9 PeBc
5、检查备份集 SfHs,y6
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' M@R_t(&=
6、修复数据库 x37pj)i/
ALTER DATABASE [dvbbs] SET SINGLE_USER L%3m_'6QP
GO xt{f+c@P
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK X?B9Z8
GO NZj_7j|o9
ALTER DATABASE [dvbbs] SET MULTI_USER ^:c:~F6J
GO h[Hn*g
7、日志清除 M=HP!hn
SET NOCOUNT ON MV+S.`R
DECLARE @LogicalFileName sysname, )JYt zc
@MaxMinutes INT, #gHs!b-g@
@NewSize INT |?a 4Nl?
USE tablename -- 要操作的数据库名 n\U3f M>N
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ]GSs{'UhB
@MaxMinutes = 10, -- Limit on time allowed to wrap log. !'ylh8}
@NewSize = 1 -- 你想设定的日志文件的大小(M) Ru1I,QvCj"
-- Setup / initialize VaLx- RX
DECLARE @OriginalSize int 8Gw0;Uu8D
SELECT @OriginalSize = size %`o3YR
FROM sysfiles k1EAmA
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WHERE name = @LogicalFileName g91X*$`]
SELECT 'Original Size of ' + db_name() + ' LOG is ' + @A-*XJNS":
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Iy2KOv@a5
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' %Pz'D6
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FROM sysfiles }!^/<|$=
WHERE name = @LogicalFileName 9/La_:K
CREATE TABLE DummyTrans 7<'4WHi;@s
(DummyColumn char (8000) not null) 3]*_*<D
DECLARE @Counter INT, :RYh@.
@StartTime DATETIME, z /
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@TruncLog VARCHAR(255) m/2LwN
SELECT @StartTime = GETDATE(), EPY64{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' (3H'!P7|~
DBCC SHRINKFILE (@LogicalFileName, @NewSize) t1y
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EXEC (@TruncLog) [CCj5N1/
-- Wrap the log if necessary. 3I rmDT
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ^t|CD|,K_O
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *2$I,
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AND (@OriginalSize * 8 /1024) > @NewSize 1|+Zmo"
BEGIN -- Outer loop. Pf?*bI
SELECT @Counter = 0 ,gvv297
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) C2~t
BEGIN -- update l1Zf#]x
INSERT DummyTrans VALUES ('Fill Log') ) \iOwA
DELETE DummyTrans hx'p0HDta
SELECT @Counter = @Counter + 1 OS
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END %*>ee[^L ,
EXEC (@TruncLog) \~3g*V
END Rh:@@4<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + B %|cp+/
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 8T}Ycm5}
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' M.h)]S>
FROM sysfiles B{:JD^V!
WHERE name = @LogicalFileName h4j{44MT
DROP TABLE DummyTrans &=seIc>x@
SET NOCOUNT OFF qyfw$$X
8、说明:更改某个表 d[b(+sHp a
exec sp_changeobjectowner 'tablename','dbo' FwdRM)1)
9、存储更改全部表 F]#rH
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch O<@S,/Q4
@OldOwner as NVARCHAR(128), U[!x
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@NewOwner as NVARCHAR(128) $@[`/Uh
AS OOa}+^-j
DECLARE @Name as NVARCHAR(128) !9$xfg}
DECLARE @Owner as NVARCHAR(128) [Rqv49n*V
DECLARE @OwnerName as NVARCHAR(128) J9tQ@3{f
DECLARE curObject CURSOR FOR Sdc
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select 'Name' = name, {AJcYZV
'Owner' = user_name(uid) ;NyX9&@
from sysobjects ;au-NY
where user_name(uid)=@OldOwner $;9zD11
order by name |j[=uS
OPEN curObject =Ws-s f]
FETCH NEXT FROM curObject INTO @Name, @Owner mP1EWh|
WHILE(@@FETCH_STATUS=0) lP4A?J+Q
BEGIN jKOjw#N
if @Owner=@OldOwner y~&R(x~w
begin |@}Yady@C
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Ha U6`IP
exec sp_changeobjectowner @OwnerName, @NewOwner :RJ=f
end 5`$.GV
-- select @name,@NewOwner,@OldOwner H#/}FoBiS
FETCH NEXT FROM curObject INTO @Name, @Owner LK
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END $"+ahS<?tC
close curObject '?q \mi
deallocate curObject SA5
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GO _L?`C
10、SQL SERVER中直接循环写入数据 U!GG8;4
declare @i int O23dtH
set @i=1 :{iS0qJ
while @i<30 t%<@k)hd~G
begin <i~MBy.
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insert into test (userid) values(@i) N2!HkUy2
set @i=@i+1 XO*|P\#^
end qusX]Tstz
小记存储过程中经常用到的本周,本月,本年函数 7=YjY)6r^
Dateadd(wk,datediff(wk,0,getdate()),-1) W9!EjXg
Dateadd(wk,datediff(wk,0,getdate()),6) 2#sJ`pdQ
Dateadd(mm,datediff(mm,0,getdate()),0) G~oGBq6Gz
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) MroJ!.9
Dateadd(yy,datediff(yy,0,getdate()),0) p Rt=5WZ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) !nQ!J+ g
上面的SQL代码只是一个时间段 4M)
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Dateadd(wk,datediff(wk,0,getdate()),-1) 9-<EeV_/
Dateadd(wk,datediff(wk,0,getdate()),6) }Q 7~tu
就是表示本周时间段. &cty&(2p
下面的SQL的条件部分,就是查询时间段在本周范围内的: -t92! O
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) >680}\S
而在存储过程中 +doZnU,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) -}l iG
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) H
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