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。 #k"1wSx16
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一、基础 jXc5fXO
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1、说明:创建数据库 d,Hf-zJ%~
CREATE DATABASE database-name j4.Qvj >:4
2、说明:删除数据库 $I?=.:<+
drop database dbname V`WI"HO+
3、说明:备份sql server gn-=##fT:i
--- 创建 备份数据的 device (2\l i{$e
USE master "r5'lQI
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' [{hL F9yPx
--- 开始 备份 6^7)GCq [
BACKUP DATABASE pubs TO testBack U'JP1\
4、说明:创建新表 Y9z:xE
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) VZUZngw
根据已有的表创建新表: ,\.YJD>z
A:create table tab_new like tab_old (使用旧表创建新表) QT7w::ht
B:create table tab_new as select col1,col2... from tab_old definition only sV9{4T~#|
5、说明:删除新表 g
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drop table tabname &.|;yt%v
6、说明:增加一个列 TKj/6Jz|
Alter table tabname add column col type ui s:\Uc
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。 T=hm#]
7、说明:添加主键: Alter table tabname add primary key(col) 'US:Mr3
说明:删除主键: Alter table tabname drop primary key(col) aRFi0h
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8、说明:创建索引:create [unique] index idxname on tabname(col....) Y!K^-Y}
删除索引:drop index idxname ;g;,%jdCS
注:索引是不可更改的,想更改必须删除重新建。 4<=eK7;XR
9、说明:创建视图:create view viewname as select statement eukX#0/^
删除视图:drop view viewname z6GL,wo#
10、说明:几个简单的基本的sql语句 cP}5}+
选择:select * from table1 where 范围 C=xo&I7
插入:insert into table1(field1,field2) values(value1,value2) 5Ws:Ei{R
删除:delete from table1 where 范围 842Mydom
更新:update table1 set field1=value1 where 范围 E9~&f^f
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {Sd@u$&
排序:select * from table1 order by field1,field2 [desc] mSVX4XW<
总数:select count as totalcount from table1 `<]P"G
求和:select sum(field1) as sumvalue from table1 DzX6U[=
平均:select avg(field1) as avgvalue from table1 v.~Nv@+kR
最大:select max(field1) as maxvalue from table1 20SF<V
最小:select min(field1) as minvalue from table1 I1eb31<
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11、说明:几个高级查询运算词 +iZ@.LI
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A: UNION 运算符 HQ-N!pf9
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。 ];YglHH
B: EXCEPT 运算符 ]ly)z[is"]
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。 $=;bccIob
C: INTERSECT 运算符 "9MX,}X*
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 7;$L&X
注:使用运算词的几个查询结果行必须是一致的。 bUipp\[aV
12、说明:使用外连接 HbJadOK
A、left outer join: 8yJk81
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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。 ;n:H6cp
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 |r<.R>
B:right outer join: $w2[5|^S
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。 juve9HaW
C:full outer join: Z(Ls#hp
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。 Px^<2Q%Fs
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二、提升 qqO10~Xc
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) B8BY3~}]
法一:select * into b from a where 1<>1 y7}~T!UyfF
法二:select top 0 * into b from a $AL|d[[T[
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) IAt+S-q0
insert into b(a, b, c) select d,e,f from b; N8/Au=De_
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) Ed ?Yk* 4
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |?pYJkrYO
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <7RkM
4、说明:子查询(表名1:a 表名2:b) l")o!N?
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) Nt,]00S\w
5、说明:显示文章、提交人和最后回复时间 Q>+_W2~]
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b hH|XtQ.n^
6、说明:外连接查询(表名1:a 表名2:b) s]V{}bY`
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c $yxIE}
7、说明:在线视图查询(表名1:a ) n=#[Mi $Y
select * from (SELECT a,b,c FROM a) T where t.a > 1; <iY 9cV|}3
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 c+\Gd}IJq
select * from table1 where time between time1 and time2 [3bwbfHhi
select a,b,c, from table1 where a not between 数值1 and 数值2 ~k:>Xo[|O
9、说明:in 的使用方法 =-a?oH-
select * from table1 where a [not] in ('值1','值2','值4','值6') y+~Aw"J}
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .,iw2:
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) l*V72!Mv
11、说明:四表联查问题: (t"YoWA#m
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 ..... PHB\)/
12、说明:日程安排提前五分钟提醒 *<
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 N]<~NG:6b
13、说明:一条sql 语句搞定数据库分页 F0o18k_"
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 Ov{B-zCA
14、说明:前10条记录 `b,g2XA
select top 10 * form table1 where 范围 G@l|u
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.) vr]dRStr
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) :L+zUlsf
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 E Zu
(select a from tableA ) except (select a from tableB) except (select a from tableC) "}azC|:5
17、说明:随机取出10条数据 ::Ve ,-0
select top 10 * from tablename order by newid() n$\6}\k
18、说明:随机选择记录 KcMzZ!d7m
select newid() Lh5+fk~i~8
19、说明:删除重复记录 l<+,(E=
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ='l6&3X
20、说明:列出数据库里所有的表名 E`Zh\u)
select name from sysobjects where type='U' #7E&16Fk
21、说明:列出表里的所有的 y5opdIaT
select name from syscolumns where id=object_id('TableName') )F9V=PJE
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 uma9yIk
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type F\$}8,9
显示结果: C8%nBa/
type vender pcs D\i8rqU/l
电脑 A 1 jind!@}!
电脑 A 1 ,hcBiL/
光盘 B 2 ?)ZLxLV::
光盘 A 2 ,\">o vV33
手机 B 3 k?_$h<Y
手机 C 3 ;:K?7wfXn
23、说明:初始化表table1 }Q,C;!'"
TRUNCATE TABLE table1 r|sy_Sk/{
24、说明:选择从10到15的记录 UW~tS
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc A UO0
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三、技巧 +r34\mAO
1、1=1,1=2的使用,在SQL语句组合时用的较多 i_Q4bhVj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 9=;g4I
如: 9H Bx[2&
if @strWhere !='' k@X
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begin [O =)FiY-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Ql!6I (
end eXtF[0f
else ~s^6Q#Z9|
begin fTnyCaB
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' S&g-
end ?_`P;}4#
我们可以直接写成 n ;fTx
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere .M#>@~XR
2、收缩数据库 &qj&WfrB,
--重建索引 E!]rh,mYK
DBCC REINDEX L&F\"q9q71
DBCC INDEXDEFRAG ;@$, "
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--收缩数据和日志 nHL>}Yg
DBCC SHRINKDB pl? J<48
DBCC SHRINKFILE B=qRZA!DQ?
3、压缩数据库 \~m%4kzG8J
dbcc shrinkdatabase(dbname) LHGK!zI
4、转移数据库给新用户以已存在用户权限 XwqfWd_
exec sp_change_users_login 'update_one','newname','oldname'
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go "gVH;<&]
5、检查备份集 pPqbD}p
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' A-NC,3
6、修复数据库 \y+F!;IxL
ALTER DATABASE [dvbbs] SET SINGLE_USER ~<Qxw>S#
GO EwJn1Mvq
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;
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GO aIyY%QT
ALTER DATABASE [dvbbs] SET MULTI_USER MhXm-<4
GO c;fyUi
7、日志清除 (3HgI
SET NOCOUNT ON 5^R#e(mr
DECLARE @LogicalFileName sysname, rAi!'vIE
@MaxMinutes INT, &S`'o%B
@NewSize INT :1Yd;%>92
USE tablename -- 要操作的数据库名 jfhDi6N
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 jF2GHyB
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #pxet
@NewSize = 1 -- 你想设定的日志文件的大小(M) #hiDZ>nr
-- Setup / initialize %y~]3XWik
DECLARE @OriginalSize int h.0&)t\q"
SELECT @OriginalSize = size 0hr)tYW,G
FROM sysfiles LGue=Hkp
WHERE name = @LogicalFileName g{.@|;d<p
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <\Dl#DH
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8c'-eT"
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' |Szr=[
FROM sysfiles ~.=HN}E
WHERE name = @LogicalFileName rY+1s^F
CREATE TABLE DummyTrans |0Ug~jKU
(DummyColumn char (8000) not null) 7o%|R2mL}
DECLARE @Counter INT, _z6u^#Si
@StartTime DATETIME, JN|#
@TruncLog VARCHAR(255) <{~UKi
SELECT @StartTime = GETDATE(), ;&:Et
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' n/|`Dz.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) =Qq^=3@h
EXEC (@TruncLog) N`:bvr
-- Wrap the log if necessary. `'t;BXedz/
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired <OFqUp*l
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 23?0'AU
AND (@OriginalSize * 8 /1024) > @NewSize PW\FcT
BEGIN -- Outer loop. V)?g4M3}
SELECT @Counter = 0 lAt1Mq}?P
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Ny<G2!W
BEGIN -- update H%jIjf
INSERT DummyTrans VALUES ('Fill Log') 4E94W,1%,Y
DELETE DummyTrans L PgI"6cP
SELECT @Counter = @Counter + 1 .EELR]`y7I
END M/I d\~
EXEC (@TruncLog) X64I~*
END Rs`Y'_B
SELECT 'Final Size of ' + db_name() + ' LOG is ' + [~0q )
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + uw&,pq
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' #GJh:#tt^
FROM sysfiles Qi L
WHERE name = @LogicalFileName _^A
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DROP TABLE DummyTrans _Pm}]Y:_
SET NOCOUNT OFF `^Sq>R!;
8、说明:更改某个表 Z0@ImhejuB
exec sp_changeobjectowner 'tablename','dbo' ]@ g$<&
9、存储更改全部表 h2*&>Mc
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ?Gu>!7
@OldOwner as NVARCHAR(128),
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@NewOwner as NVARCHAR(128) ZOsn,nF
AS ml/O
DECLARE @Name as NVARCHAR(128) J<O_N~$$*
DECLARE @Owner as NVARCHAR(128) DN_C7\CoA
DECLARE @OwnerName as NVARCHAR(128) SuuS!U+i>
DECLARE curObject CURSOR FOR RlL,eU$CS
select 'Name' = name, f.CI.aozW
'Owner' = user_name(uid) ~n\ea:.
from sysobjects -L3RzX
where user_name(uid)=@OldOwner ^@> Qiy
order by name +Ea XS
OPEN curObject X Y?@^
FETCH NEXT FROM curObject INTO @Name, @Owner )o,0aGo>Of
WHILE(@@FETCH_STATUS=0) @=1``z#
BEGIN }Elce}
if @Owner=@OldOwner 1#uw^{n
begin ^!tI+F{n{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) .k(_j.v
exec sp_changeobjectowner @OwnerName, @NewOwner md
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end `v
er "s;
-- select @name,@NewOwner,@OldOwner 9D21e(7X
FETCH NEXT FROM curObject INTO @Name, @Owner qa?y lR"kA
END gWPa8q<b
close curObject 2J;CiEB
deallocate curObject +.uk#K0o
GO tYa*%|!v
10、SQL SERVER中直接循环写入数据 bS6Yi)p
declare @i int s]>%_(5
set @i=1 TD9`SSpP
while @i<30 u'."E7o#
begin GC3L2C0)k
insert into test (userid) values(@i) 8B9zo&
set @i=@i+1 4Fq}*QJ-
end c,ek]dTj
小记存储过程中经常用到的本周,本月,本年函数
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Dateadd(wk,datediff(wk,0,getdate()),-1) *5)!y
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Dateadd(wk,datediff(wk,0,getdate()),6) >$F]Ss)$
Dateadd(mm,datediff(mm,0,getdate()),0) ]vErF=[U,
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,oil}N(
Dateadd(yy,datediff(yy,0,getdate()),0) 8m0sEV>
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) dG+xr!
上面的SQL代码只是一个时间段 *@^0xz{\z
Dateadd(wk,datediff(wk,0,getdate()),-1) zBfBYhS-
Dateadd(wk,datediff(wk,0,getdate()),6) j&5Xjl>4
就是表示本周时间段. :Yqa[._AF
下面的SQL的条件部分,就是查询时间段在本周范围内的: _Ohq'ZgXm
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) aoS1Yt'@
而在存储过程中 r0>T7yPAK
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 3\7$)p+c
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qiN'Tuw9