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。 }u&JX
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一、基础 u|ZO"t
1、说明:创建数据库 3LmHH
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CREATE DATABASE database-name oMPQkj;
2、说明:删除数据库 6i4j(P
drop database dbname V;V9_qP,
3、说明:备份sql server \5Jv;gc\\
--- 创建 备份数据的 device p
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USE master +D@R'$N
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?,NAihN]
--- 开始 备份 "duJl-
BACKUP DATABASE pubs TO testBack {x:IsQZ
4、说明:创建新表 K+\hv~+@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) r$7rYxFR
根据已有的表创建新表: ;1%a:#5
A:create table tab_new like tab_old (使用旧表创建新表) )&9RoW()?
B:create table tab_new as select col1,col2... from tab_old definition only #59zv=
5、说明:删除新表 _=MWt_A '3
drop table tabname .EcM n
6、说明:增加一个列 8n)Q^z+
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Alter table tabname add column col type h2>0#Vp3j
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 -&?-
7、说明:添加主键: Alter table tabname add primary key(col) /p>[$`Aq
说明:删除主键: Alter table tabname drop primary key(col) `FwAlYJK
8、说明:创建索引:create [unique] index idxname on tabname(col....) krA))cP
删除索引:drop index idxname { SfU!
注:索引是不可更改的,想更改必须删除重新建。 `g=~u{0
9、说明:创建视图:create view viewname as select statement *pMA
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删除视图:drop view viewname !xI![N^
10、说明:几个简单的基本的sql语句 =Vs<DO{|4q
选择:select * from table1 where 范围 H[r0jREK
插入:insert into table1(field1,field2) values(value1,value2) lg1D>=(mY
删除:delete from table1 where 范围 S&*pR3,u
更新:update table1 set field1=value1 where 范围 j66@E\dN
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! )B_h"5X4\y
排序:select * from table1 order by field1,field2 [desc] b<n)`;
总数:select count as totalcount from table1 %?fzT+-=%
求和:select sum(field1) as sumvalue from table1 H4,yuV
平均:select avg(field1) as avgvalue from table1 )sHPIxHI
最大:select max(field1) as maxvalue from table1 C#Jj;Gd
最小:select min(field1) as minvalue from table1 %vXQ Sz
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11、说明:几个高级查询运算词 Mx"tUoU6z
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A: UNION 运算符 q4{ t H
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。 Fn,|J[sC
B: EXCEPT 运算符 GLyh1qNX
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。 TE~@Bl;{?c
C: INTERSECT 运算符 H JiP:{
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。 sYpogFfV
注:使用运算词的几个查询结果行必须是一致的。 [w f12P
12、说明:使用外连接 [78
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A、left outer join: @Hh"Y1B
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。 B}X#oA
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 e=jO_[
B:right outer join: 7Cf(y'w^
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。 bSLj-vp
C:full outer join: AHGcWS\,X
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。 =&b[V"
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二、提升 V{{x~Q9
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) YqgW8EM
法一:select * into b from a where 1<>1 k6BgY|0g C
法二:select top 0 * into b from a 4&D="GA
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) @:B1
insert into b(a, b, c) select d,e,f from b; >gJWp@6V
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) qgNK!(kWpr
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 =6&D4~R
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ^q\zC%.
4、说明:子查询(表名1:a 表名2:b) LS'=>s"
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) 0
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5、说明:显示文章、提交人和最后回复时间 '9@R=#nd
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "[yiNJ"kt
6、说明:外连接查询(表名1:a 表名2:b) vuBA&j0C
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c T"U t).
7、说明:在线视图查询(表名1:a ) 8BDL{?Mu
select * from (SELECT a,b,c FROM a) T where t.a > 1; Umg81!
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 WKsx|a]U
select * from table1 where time between time1 and time2 Phu|
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select a,b,c, from table1 where a not between 数值1 and 数值2 Sj?sw]3
9、说明:in 的使用方法 R:?vY!
select * from table1 where a [not] in ('值1','值2','值4','值6') `x)bw
10、说明:两张关联表,删除主表中已经在副表中没有的信息 sdQv:nd'R
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 1#"Q' ,7
11、说明:四表联查问题: 4a!7|}W
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 I C? S
12、说明:日程安排提前五分钟提醒 ,~(}lvqVH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 G`"Cqs<
13、说明:一条sql 语句搞定数据库分页 uszSFe]E
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 )AXH^&
14、说明:前10条记录 }3w b*,Sbz
select top 10 * form table1 where 范围 VhgEG(Ud
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.) WmUW
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) A#&qoZ(C
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 (p=GR#
(select a from tableA ) except (select a from tableB) except (select a from tableC) R"`{E,yj
17、说明:随机取出10条数据 `gN68:B
select top 10 * from tablename order by newid() "|`9{/]
18、说明:随机选择记录 0!`7kZrN
select newid() rJp6d :M
19、说明:删除重复记录 ]bb}[#AY
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) C}_:K)5q
20、说明:列出数据库里所有的表名 Y{RB\}f(
select name from sysobjects where type='U' F*VMS
21、说明:列出表里的所有的 [oLQd-+
select name from syscolumns where id=object_id('TableName') =hIT?Z6A
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 ;um
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 !!%[JR)cS
显示结果: +t4m\/y
type vender pcs DAHf&/JK
电脑 A 1 vqMk)htIz
电脑 A 1 9dtGqXX
光盘 B 2 &> .1%x@R
光盘 A 2 @;D}=$x
手机 B 3 MmH_gR
手机 C 3 KxmPL
23、说明:初始化表table1 ID# qKFFW
TRUNCATE TABLE table1 &xroms"S=
24、说明:选择从10到15的记录 j%jd@z ]@
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc O&iYGREO
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三、技巧 x9A
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1、1=1,1=2的使用,在SQL语句组合时用的较多 %L>nXj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, `)M\(_
如: iCRw}[[
if @strWhere !='' '8kjTf#g<l
begin Sx9:$"3.X
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 9w;J7jgOT!
end :;q_f+U
else 1[g!^5W
begin Fi%W\Y'
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' gzCMJ<3!D
end
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我们可以直接写成 Cmx2/N
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere F%Umau*1
2、收缩数据库 =z1o}ga=EA
--重建索引 wx%nTf/Oa
DBCC REINDEX ^@lg5d3F
DBCC INDEXDEFRAG m:fouMS
--收缩数据和日志 [j]J_S9jJ
DBCC SHRINKDB ec4%Wk2
DBCC SHRINKFILE ]!G>8Rc
3、压缩数据库 bSR+yr'?
dbcc shrinkdatabase(dbname) _JJKbi
4、转移数据库给新用户以已存在用户权限 emY5xZ@N
exec sp_change_users_login 'update_one','newname','oldname' vs)I pV(
go GL =XiBt
5、检查备份集 s8Ry}{
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' V/9"Xmv75
6、修复数据库 o / g+Z
ALTER DATABASE [dvbbs] SET SINGLE_USER D4O5@KfL
GO aU<D$I
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK *8X9lv.Z
GO qvU$9cTY
ALTER DATABASE [dvbbs] SET MULTI_USER
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GO yX.5Y|A<
7、日志清除 ElR&scXi__
SET NOCOUNT ON +<WRB\W
DECLARE @LogicalFileName sysname, NU&^7[!yl
@MaxMinutes INT, KR+BuL+L
@NewSize INT 4B8S e
USE tablename -- 要操作的数据库名 Y:!/4GF
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 xCp+<|1
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ?~JxO/K
@NewSize = 1 -- 你想设定的日志文件的大小(M) pY!dG-;
-- Setup / initialize |8qK%n f}
DECLARE @OriginalSize int N'
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SELECT @OriginalSize = size v7<S F
FROM sysfiles Prb_/B Dd
WHERE name = @LogicalFileName h9BD
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + a;'E}b{`F
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + x #X#V\w=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' .1}rzh}8
FROM sysfiles ]AZ\5C-J
WHERE name = @LogicalFileName M`+e'vdw
CREATE TABLE DummyTrans *JY`.t
(DummyColumn char (8000) not null) O})u'
DECLARE @Counter INT, J={OOj
@StartTime DATETIME, H")N_BB
@TruncLog VARCHAR(255) /=YqjZTCq
SELECT @StartTime = GETDATE(), yg-FJ/
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' MpIw^a3(r
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Pm#x?1rAj
EXEC (@TruncLog) (o6[4( G
-- Wrap the log if necessary. tk)>CK11
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired |IX` (
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 3aE[F f[
AND (@OriginalSize * 8 /1024) > @NewSize ^M(`/1 :
BEGIN -- Outer loop. R2Rstk
SELECT @Counter = 0 (O_t5<A*X
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 2Z;`#{
BEGIN -- update 0qL
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INSERT DummyTrans VALUES ('Fill Log') XAU_SPAjiw
DELETE DummyTrans /,Dwu?Lcqp
SELECT @Counter = @Counter + 1 ]o[X+;Tj|
END eC^0I78x
EXEC (@TruncLog) v(Bp1~PPZM
END %eJ\d?nw
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 3r-Vx P 5n
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + [}p
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' PJK]t7vp
FROM sysfiles fY%M=,t3c
WHERE name = @LogicalFileName jW1YTQ
DROP TABLE DummyTrans wj#J>C2]
SET NOCOUNT OFF ]D?# \|
8、说明:更改某个表 Z(LxB$^l[
exec sp_changeobjectowner 'tablename','dbo' 8yE%X!E
9、存储更改全部表 h8#5vO2
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch dE5 5
@OldOwner as NVARCHAR(128), yxG:\y
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@NewOwner as NVARCHAR(128) lRv#1'Y
AS esh$*)1
DECLARE @Name as NVARCHAR(128) u 5Eo
DECLARE @Owner as NVARCHAR(128) z{`6#
DECLARE @OwnerName as NVARCHAR(128) ;zZ ,3pl-E
DECLARE curObject CURSOR FOR ovQS
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select 'Name' = name, LZUA+ x(
'Owner' = user_name(uid) (zS2Ndp
from sysobjects ^.@yF;H
where user_name(uid)=@OldOwner |C$:]MZx
order by name i?a,^UM5n[
OPEN curObject (0OSGG9
FETCH NEXT FROM curObject INTO @Name, @Owner C7b
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WHILE(@@FETCH_STATUS=0) 95$pG/o
BEGIN 6^]`-4*W
if @Owner=@OldOwner @Xq&t}*8
begin 5 Q6{(q|M
set @OwnerName = @OldOwner + '.' + rtrim(@Name) MK-a$~<
exec sp_changeobjectowner @OwnerName, @NewOwner h9<mThvgn
end nszpG1U:
-- select @name,@NewOwner,@OldOwner UzU-eyA
FETCH NEXT FROM curObject INTO @Name, @Owner ^e aRgNz
END 5:*5j@/S
close curObject H5AK n*'7
deallocate curObject Avs7(-L+s
GO ZRXI?Jr%
10、SQL SERVER中直接循环写入数据 MfXt+c`r
declare @i int v:veV. y
set @i=1 f.b8ZBNj>
while @i<30 4Q$j]U&b
begin ?JXBWB4
insert into test (userid) values(@i) 670J{b
set @i=@i+1 pAJ=f}",]E
end j*;*Ka w
小记存储过程中经常用到的本周,本月,本年函数 Z7/vrME6
Dateadd(wk,datediff(wk,0,getdate()),-1) m\*&2Na
Dateadd(wk,datediff(wk,0,getdate()),6) ~:/%/-^
Dateadd(mm,datediff(mm,0,getdate()),0) ``(}4a
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 1-6gB@cvQ
Dateadd(yy,datediff(yy,0,getdate()),0) :S QDqG
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) < 72s7*Rv
上面的SQL代码只是一个时间段 A$9q!Ui#d
Dateadd(wk,datediff(wk,0,getdate()),-1) |u^)RB
Dateadd(wk,datediff(wk,0,getdate()),6) <S\;k@f
就是表示本周时间段. wUru1_zjO
下面的SQL的条件部分,就是查询时间段在本周范围内的: Ud>`@2
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ee&nU(pK
而在存储过程中 $xRo<,OV+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) zQL!(2
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) F-$Z,Q]S