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。 E<a~
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一、基础 "0g1'az}
1、说明:创建数据库 &K`[SX=
CREATE DATABASE database-name $xS `i-|
2、说明:删除数据库 ;G~0 VM2|
drop database dbname 9h$-:y3
3、说明:备份sql server ;P _`4w3
--- 创建 备份数据的 device a7q-*%+d5
USE master :f^O!^N
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 1`m ~c
--- 开始 备份 yaA9*k
BACKUP DATABASE pubs TO testBack W?'!}g(~
4、说明:创建新表 x-U^U.i@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Uz H)fB
根据已有的表创建新表: gW6lMyiLb
A:create table tab_new like tab_old (使用旧表创建新表) bs]ret$?(q
B:create table tab_new as select col1,col2... from tab_old definition only |zvxKIW;wd
5、说明:删除新表 y3$'
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drop table tabname Vk$zA<sw"
6、说明:增加一个列 N:clwmo
Alter table tabname add column col type KL0u:I(lWU
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。 G_[|N>
7、说明:添加主键: Alter table tabname add primary key(col) *Yvfp{B
说明:删除主键: Alter table tabname drop primary key(col) $Kb-mFR
8、说明:创建索引:create [unique] index idxname on tabname(col....) FWdSpaas Q
删除索引:drop index idxname >9=Y(`
注:索引是不可更改的,想更改必须删除重新建。 TRAs5I%
9、说明:创建视图:create view viewname as select statement q?Q"Ab
删除视图:drop view viewname n\*>mp)
10、说明:几个简单的基本的sql语句 ` /]8C&u
选择:select * from table1 where 范围 =X>3C"]
插入:insert into table1(field1,field2) values(value1,value2) 42Vy#t/HC
删除:delete from table1 where 范围 *s?&)][
更新:update table1 set field1=value1 where 范围 &6MGPh7T
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! N"T~U\R
排序:select * from table1 order by field1,field2 [desc] t22BO@gt74
总数:select count as totalcount from table1 n`6 8<ybl5
求和:select sum(field1) as sumvalue from table1 kd'qYh
平均:select avg(field1) as avgvalue from table1 rEdr8qw
最大:select max(field1) as maxvalue from table1 Cz?N[dhh
最小:select min(field1) as minvalue from table1 !V@Y \M
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11、说明:几个高级查询运算词 Y#{KGVT<
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A: UNION 运算符 =t&B8+6
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。 o|l)oc6{
B: EXCEPT 运算符 n1uJQt
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。 v2EM| Q xp
C: INTERSECT 运算符 cGsxfwD
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。 6l [TQ
注:使用运算词的几个查询结果行必须是一致的。 p4Vw`i+DnH
12、说明:使用外连接 ;b
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A、left outer join: \#2,1W@
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。 +5?hkQCX1^
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 D}cq_|mmn[
B:right outer join: MY9?957F
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。 ?8! 4!P%n
C:full outer join: i3;Z:,A4NN
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。 z=>]E1'RL
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二、提升 qg:1
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) N_q7ip%z
法一:select * into b from a where 1<>1 lUCdnp;w'
法二:select top 0 * into b from a %~^R Iwm
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) [JMz~~F
insert into b(a, b, c) select d,e,f from b; SY <!-g<1F
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) xfO!v>
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 *qY`MW
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. '4dnC2a]
4、说明:子查询(表名1:a 表名2:b) _h@7>+vl~
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) :
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5、说明:显示文章、提交人和最后回复时间 pVt-7AgW
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b I g-VSQ
6、说明:外连接查询(表名1:a 表名2:b) Mk|h ><Q"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c '$1-A%e$1
7、说明:在线视图查询(表名1:a ) F2oY_mA
select * from (SELECT a,b,c FROM a) T where t.a > 1; 'D\(p,(Mt
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 8dIgw
select * from table1 where time between time1 and time2 i]hFiX
select a,b,c, from table1 where a not between 数值1 and 数值2 wOHK
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9、说明:in 的使用方法 g6QkF41nG
select * from table1 where a [not] in ('值1','值2','值4','值6') Gu*;z% b2
10、说明:两张关联表,删除主表中已经在副表中没有的信息 XuR!9x^5
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7F\U|kx_
11、说明:四表联查问题: s;8J= \9W
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 ..... NO`a2HR$
12、说明:日程安排提前五分钟提醒 )dC%g=dtc
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8-juzL}
13、说明:一条sql 语句搞定数据库分页 =kZPd>&L
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 go2:D#mf
14、说明:前10条记录 \^N9Q9{7]
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.) j*W]^uT,
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 5>}L3r>a;
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~<fw]y
(select a from tableA ) except (select a from tableB) except (select a from tableC) [_-CO}>
17、说明:随机取出10条数据 vj?9X5A_
select top 10 * from tablename order by newid() HEjV7g0E
18、说明:随机选择记录 4y
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select newid() dHf_&X2A
19、说明:删除重复记录 vWe)c J
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...)
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20、说明:列出数据库里所有的表名 _~Lhc'^p*
select name from sysobjects where type='U' C&<f YCwG
21、说明:列出表里的所有的 OX|/yw8
select name from syscolumns where id=object_id('TableName') ?$-OdABXHK
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 u4z]6?,"e
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type uZmfvMr3
显示结果: lP9a*>=a
type vender pcs Xb$)}n\9
电脑 A 1 ~+3f8%
电脑 A 1 6<]&T lS]
光盘 B 2 #0G9{./C
光盘 A 2 1vl~[
手机 B 3 tEiN(KA!5
手机 C 3 &z1r$X.AW
23、说明:初始化表table1 !c(B^E
TRUNCATE TABLE table1 7:M%w'oR
24、说明:选择从10到15的记录 bhe|q`1,E
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc NYR^y\u
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三、技巧 UvQxtT]
1、1=1,1=2的使用,在SQL语句组合时用的较多 7OC,KgJ3
"where 1=1" 是表示选择全部 "where 1=2"全部不选, eSa ]6
如: :l3Tt<
if @strWhere !='' P>4(+s
begin TKRu^KH9
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere w:MfaN*
end nfrC@Av
else C@]Z&H;
begin 1|z>}
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' p+9vSM #
end .O1g'%
我们可以直接写成 8{Zgvqbb
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Q*mPU=<
2、收缩数据库 A[oi?.D
--重建索引 5f}63as
DBCC REINDEX G_42ckLq
DBCC INDEXDEFRAG 2+"#
--收缩数据和日志 N<N!it
DBCC SHRINKDB r<&d1fM;X
DBCC SHRINKFILE dBobVT'
3、压缩数据库 'ky'GzX,
dbcc shrinkdatabase(dbname) w?!@fu
4、转移数据库给新用户以已存在用户权限 l Fzb$k}_{
exec sp_change_users_login 'update_one','newname','oldname' Q^fli"_:
go E@t~juF!
5、检查备份集 ,6a'x~y<r
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' TmzEZ<} &7
6、修复数据库
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ALTER DATABASE [dvbbs] SET SINGLE_USER [Y'Xop6G
GO ,a5I:V^\
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK DOU\X N
GO X`J~3s
ALTER DATABASE [dvbbs] SET MULTI_USER 5G\vV]RR&
GO G9Xrwk<g4
7、日志清除 pw- C=MY]
SET NOCOUNT ON ]d% hU
DECLARE @LogicalFileName sysname, Q4c>gds`
@MaxMinutes INT, YEVH?`G
@NewSize INT )5&w
USE tablename -- 要操作的数据库名 l)XzU&Sc~
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 oWx!
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~2rZL
@NewSize = 1 -- 你想设定的日志文件的大小(M) ?LvZEiJ
-- Setup / initialize HK:?Y[ebs
DECLARE @OriginalSize int
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SELECT @OriginalSize = size n!3_%K0!r&
FROM sysfiles G'{4ec0<{
WHERE name = @LogicalFileName q ,}W.
SELECT 'Original Size of ' + db_name() + ' LOG is ' + /A<L
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 2,NQ(c_c$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 6PvV X*5T
FROM sysfiles kCN9`9XI{
WHERE name = @LogicalFileName \!G&:<h
CREATE TABLE DummyTrans 1[X+6viE
(DummyColumn char (8000) not null) q\mVZyj
DECLARE @Counter INT, K[T?--H
@StartTime DATETIME, 5;dnxhf
@TruncLog VARCHAR(255) Du[$6
SELECT @StartTime = GETDATE(), j>?c]h{-
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 4V<s"
DBCC SHRINKFILE (@LogicalFileName, @NewSize) `+]4C+w
EXEC (@TruncLog) BhdJ/C^
-- Wrap the log if necessary. FeSe^ ^dW
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired M@s2T|bQw
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) oqUtW3y
AND (@OriginalSize * 8 /1024) > @NewSize g<}K^)x
BEGIN -- Outer loop. [gH
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SELECT @Counter = 0 =<a`G3SY!
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) W~dS8B=<
BEGIN -- update \7gLk:
INSERT DummyTrans VALUES ('Fill Log') 9Z
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DELETE DummyTrans fTV:QAa;
SELECT @Counter = @Counter + 1 bnUd !/;
END =3/||b4c
EXEC (@TruncLog) j<wg>O:s%r
END ` [@
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + MH!'g7iK8
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + d;;]+%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' R2t5T-8`c
FROM sysfiles #Du1(R
WHERE name = @LogicalFileName 7c4\'dt#
DROP TABLE DummyTrans z#bOFVg#
SET NOCOUNT OFF h7I_{v8
8、说明:更改某个表 qrm~=yU%
exec sp_changeobjectowner 'tablename','dbo' *>S\i7RET
9、存储更改全部表 Td"f(&Hk&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch }2V|B4
@OldOwner as NVARCHAR(128), 3x'BMAA+
@NewOwner as NVARCHAR(128) V><5N;w
AS &W`yHQ"JY
DECLARE @Name as NVARCHAR(128) rJ9a@n,
DECLARE @Owner as NVARCHAR(128) "E8-76n
DECLARE @OwnerName as NVARCHAR(128) ,Iwri\
DECLARE curObject CURSOR FOR H%Q@DW8~@
select 'Name' = name, #N@sJyIN
'Owner' = user_name(uid) VJZ
from sysobjects EvQN (_
where user_name(uid)=@OldOwner (ioi !p
order by name ~i6tcd
OPEN curObject 3H@TvV/;f
FETCH NEXT FROM curObject INTO @Name, @Owner i<)c4
WHILE(@@FETCH_STATUS=0) N`8?bU7a}"
BEGIN ^Zydy
if @Owner=@OldOwner V0ulIKck
begin ]rC6fNhQ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) CKNH/[ZR,
exec sp_changeobjectowner @OwnerName, @NewOwner l)=Rj`M
end C!RxMccTh
-- select @name,@NewOwner,@OldOwner GwW!Q|tVz=
FETCH NEXT FROM curObject INTO @Name, @Owner I)Lg=n$
END 9[6xo!
close curObject i&{8a3B
deallocate curObject (Dq3e9fX
GO \W}?4kz
10、SQL SERVER中直接循环写入数据 !=|3^A
declare @i int [
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set @i=1 Bb8lklQ
while @i<30 ]}~*uT}>
begin )k <ON~x
insert into test (userid) values(@i) O' A''}M
set @i=@i+1 m0XK?;\V
end 3DMfR
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小记存储过程中经常用到的本周,本月,本年函数 VX2bC(E'%
Dateadd(wk,datediff(wk,0,getdate()),-1) |giK]Z
Dateadd(wk,datediff(wk,0,getdate()),6) V:F)m!
Dateadd(mm,datediff(mm,0,getdate()),0) 9'td}S
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &hyr""NkAm
Dateadd(yy,datediff(yy,0,getdate()),0) EJb"/oLla
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ?Z*LTsPr
上面的SQL代码只是一个时间段 2syKYHV
Dateadd(wk,datediff(wk,0,getdate()),-1) Ny
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Dateadd(wk,datediff(wk,0,getdate()),6) OUnt?[U\
就是表示本周时间段. B5zu?AG
下面的SQL的条件部分,就是查询时间段在本周范围内的: li%=<?%T
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) YeYFPi#
而在存储过程中 8O("o7~"
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) HQ ^> ~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) .+|G`*1<i