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。 AQmHa2P
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一、基础 9zY6hh**
1、说明:创建数据库 vrcIwCa
CREATE DATABASE database-name *"OUwEl a
2、说明:删除数据库 5DVYHN9c|
drop database dbname b` va\'&3
3、说明:备份sql server ~]q>}/&YLo
--- 创建 备份数据的 device n4y]h
USE master fP\q?X@]E
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 'C]Yh."u
--- 开始 备份 )]s<Czm%
BACKUP DATABASE pubs TO testBack 52zE -SY
4、说明:创建新表 i1!1'T8
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [:cvy[}v@
根据已有的表创建新表: =E<H_cUS
A:create table tab_new like tab_old (使用旧表创建新表) }pIn3B)
B:create table tab_new as select col1,col2... from tab_old definition only D
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5、说明:删除新表 !?=U{^|7y
drop table tabname _^NyLI%
6、说明:增加一个列 t"Ah]sD
Alter table tabname add column col type FSn3p}FVa
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。 6)7cw8^
7、说明:添加主键: Alter table tabname add primary key(col) B(k tIy
说明:删除主键: Alter table tabname drop primary key(col) imeE&
8、说明:创建索引:create [unique] index idxname on tabname(col....) ,Aai-AGG@
删除索引:drop index idxname /;Hr{f jl{
注:索引是不可更改的,想更改必须删除重新建。 b $JS|
9、说明:创建视图:create view viewname as select statement @Z2np{X:
删除视图:drop view viewname D:f=Z?L)>
10、说明:几个简单的基本的sql语句 Od)y4nr3~
选择:select * from table1 where 范围 gdA2u;q
插入:insert into table1(field1,field2) values(value1,value2) H!&_Tv[
删除:delete from table1 where 范围 Tjhy@3
更新:update table1 set field1=value1 where 范围 (zsv!U
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! F"UI=7:o
排序:select * from table1 order by field1,field2 [desc] 6 dV )pJd
总数:select count as totalcount from table1 40pz <-B
求和:select sum(field1) as sumvalue from table1 D>-r `
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 8-Y*b89
最小:select min(field1) as minvalue from table1 L!lmy&1
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11、说明:几个高级查询运算词 -5 D<zP/
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A: UNION 运算符 %9a3$OGZX
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。 mfN'+`r
B: EXCEPT 运算符 5af0- hj
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。 brs`R#e \
C: INTERSECT 运算符 IEMa/[n/
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。 -v.\W y~\
注:使用运算词的几个查询结果行必须是一致的。 ?5J#
12、说明:使用外连接 5l
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A、left outer join: _io'8X2K%
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。 Uq$/Q7
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .<F46?HS
B:right outer join: `SsoRPW&$
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。 >%om[]0E
C:full outer join: b%%r`j,'JE
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。 !Yv_V]u=
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二、提升 o3/o2[s
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) #-<Go'yF
法一:select * into b from a where 1<>1 4&sf{tI
法二:select top 0 * into b from a ?'z/S5&j
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^2nrA pF
insert into b(a, b, c) select d,e,f from b; %,_ZVgh0
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) Xt<1b
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 lz~^*\ F
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ekL;SN
4、说明:子查询(表名1:a 表名2:b) wlJi_)!
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 <D ~hhGb
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b rB$~,q&.V
6、说明:外连接查询(表名1:a 表名2:b) ,MNv}w@
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c '<BLkr# @
7、说明:在线视图查询(表名1:a ) t]@>kAA>2L
select * from (SELECT a,b,c FROM a) T where t.a > 1; jDpA>{O[
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 94BH{9b5
select * from table1 where time between time1 and time2 ={sjoMW
select a,b,c, from table1 where a not between 数值1 and 数值2 z3K$gEve
9、说明:in 的使用方法 3NLn}
select * from table1 where a [not] in ('值1','值2','值4','值6') i[IFD]Xy!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 Lo{wTYt:J
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 )
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11、说明:四表联查问题: XGR2L
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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 ..... s@ @Km1w
12、说明:日程安排提前五分钟提醒 A-T-4I
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 w\o6G7
13、说明:一条sql 语句搞定数据库分页 W~;Jsd=f
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 u9OY
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14、说明:前10条记录 AX8~w(sv
select top 10 * form table1 where 范围 <VKJ+
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.) -je} PwT
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) t-iXY0%&
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 b;UBvwY_
(select a from tableA ) except (select a from tableB) except (select a from tableC) tfGs|x
17、说明:随机取出10条数据 R+Hu?Dv&F
select top 10 * from tablename order by newid() hbH~Ya=+S
18、说明:随机选择记录 e"%TU
select newid() gHBv Q1g
19、说明:删除重复记录 $h{m")]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) :^3 )[.m
20、说明:列出数据库里所有的表名 ;rT'~?q
select name from sysobjects where type='U' cQ j`W
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21、说明:列出表里的所有的 I"88O4\@
select name from syscolumns where id=object_id('TableName') +9b{Y^^~T
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 KHML!f=mu
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type S@HC$
显示结果: 7sxX?u
type vender pcs hi1Ial\Y
电脑 A 1 Y0 a[Lb0
电脑 A 1 s Z[[ymu8
光盘 B 2 0vm> *M*p
光盘 A 2 hLLSmW(
手机 B 3 O D}RnKL
手机 C 3 ~~OFymQ%?q
23、说明:初始化表table1 **hQb$
TRUNCATE TABLE table1 P[
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24、说明:选择从10到15的记录 OB(oOPH
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc x950,`zy
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三、技巧 ,*XB11P
1、1=1,1=2的使用,在SQL语句组合时用的较多 Q%JI-&K
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~Kw#^.$3T
如: ~V8z%s@
if @strWhere !='' #{q.s[g*+1
begin d2`g,~d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere P"_/P8
end n^4R]9U
else 2Cz haO
begin ;|5-{+2 U%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' $9,&BW_*
end p0@^1
我们可以直接写成 GEWjQ;g
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere v745FIy<
2、收缩数据库 )@N d3Z
--重建索引 ZZT #V%Q=u
DBCC REINDEX ,0W^"f.g{m
DBCC INDEXDEFRAG ^HC6v;K
--收缩数据和日志 6eV#x%z@v'
DBCC SHRINKDB Jbu2y'zE
DBCC SHRINKFILE bqcCA91
3、压缩数据库 1D*=ZkA)
dbcc shrinkdatabase(dbname) 1|MRXK
4、转移数据库给新用户以已存在用户权限 ]y0Y (
exec sp_change_users_login 'update_one','newname','oldname' h3CA,$HJ
go SndR:{
5、检查备份集 F^u12R)
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' >NKJ@4Y
6、修复数据库 xs{pGQ6Q
ALTER DATABASE [dvbbs] SET SINGLE_USER ?R)]D:`
GO Z>9@)wo
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ,dIev<
GO Y$=jAN
ALTER DATABASE [dvbbs] SET MULTI_USER
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GO j]BRf A
7、日志清除 Tlw'05\{J
SET NOCOUNT ON 7Z6=e6/\
DECLARE @LogicalFileName sysname, ,|]JaZq
@MaxMinutes INT, nq M7Is
@NewSize INT p~$cwbQ!
USE tablename -- 要操作的数据库名 O(T5
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1r;zA<<%R
@MaxMinutes = 10, -- Limit on time allowed to wrap log. *&NP?-E
@NewSize = 1 -- 你想设定的日志文件的大小(M) w 9dkJo
-- Setup / initialize F` U~(>u'
DECLARE @OriginalSize int `6U!\D
SELECT @OriginalSize = size ` =>}*GS
FROM sysfiles u:l-qD9=(
WHERE name = @LogicalFileName entU+O r
SELECT 'Original Size of ' + db_name() + ' LOG is ' + -'&/7e6>y
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + =>$)F 4LW
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ]||b2[*
FROM sysfiles q)k:pQ
WHERE name = @LogicalFileName KNVu[P)rv
CREATE TABLE DummyTrans 928_e)V
(DummyColumn char (8000) not null) ue_wuZi
DECLARE @Counter INT, '$9o(m#
@StartTime DATETIME, YWFE*wQ!
@TruncLog VARCHAR(255) oW3"J6,S
SELECT @StartTime = GETDATE(), m@Z#
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' $h#sb4ek
DBCC SHRINKFILE (@LogicalFileName, @NewSize) OEW'bT)
EXEC (@TruncLog) ETp?R WXX
-- Wrap the log if necessary. %O"8|ZG9{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired mO>L]<O
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Pyo|Sgk
AND (@OriginalSize * 8 /1024) > @NewSize dHnCSOM<
BEGIN -- Outer loop. I!sT=w8V
SELECT @Counter = 0 &$MC!iMh
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) aGD< #]
BEGIN -- update C96/
INSERT DummyTrans VALUES ('Fill Log') R_!.vGhkN
DELETE DummyTrans P%3pM*.
SELECT @Counter = @Counter + 1 8z9{H
END p`"k=tZ{
EXEC (@TruncLog) aB,-E>+
END NAR6q{c
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6Tl6A>%s
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 5n@YNaoIb
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 4>KF`?%4
FROM sysfiles X6Ha C+P
WHERE name = @LogicalFileName Su#0F0
DROP TABLE DummyTrans ![_x/F9
SET NOCOUNT OFF `'YX>u /
8、说明:更改某个表 idI w7hi4
exec sp_changeobjectowner 'tablename','dbo' [YDSS/
9、存储更改全部表 s3>a
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch kKX' Y+
@OldOwner as NVARCHAR(128), B~]Kqp7yU
@NewOwner as NVARCHAR(128)
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AS XqTguO'
DECLARE @Name as NVARCHAR(128) }p)K6!J0
DECLARE @Owner as NVARCHAR(128) @oXGa>Ru
DECLARE @OwnerName as NVARCHAR(128) D-gH_ff<]9
DECLARE curObject CURSOR FOR IG^@VQ%
select 'Name' = name, ')m!48
'Owner' = user_name(uid) jP+yN|
from sysobjects 28MMH
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where user_name(uid)=@OldOwner qN!oN*
order by name 9zp!lw~;+
OPEN curObject Q0U~s\<
FETCH NEXT FROM curObject INTO @Name, @Owner wI%M3XaBws
WHILE(@@FETCH_STATUS=0) B8@mL-Z-;
BEGIN i^s Vy
if @Owner=@OldOwner &.)=>2
begin |2(q9j
set @OwnerName = @OldOwner + '.' + rtrim(@Name) +:MSY p
exec sp_changeobjectowner @OwnerName, @NewOwner @Cj!MZ=T
end $RD~,<oEm
-- select @name,@NewOwner,@OldOwner ?cV,lak
FETCH NEXT FROM curObject INTO @Name, @Owner NoI|Dz
END o4Q?K.9c
close curObject QYH-"-)
deallocate curObject \nl(tU#j
GO ].d2C J'
10、SQL SERVER中直接循环写入数据 @^,q/%;
declare @i int >ahDc!Jyu
set @i=1 `^M]|7
while @i<30 IskL$Y ^
begin \]X.f&u
insert into test (userid) values(@i) l]*RiK2AC
set @i=@i+1 R/hf"E1
end r4yz{^G
小记存储过程中经常用到的本周,本月,本年函数 eM7@!CdA9q
Dateadd(wk,datediff(wk,0,getdate()),-1) (,|,j(=]
Dateadd(wk,datediff(wk,0,getdate()),6) W`>|OiuF
Dateadd(mm,datediff(mm,0,getdate()),0) ;: ;E|{e
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) aKI"<%PNn
Dateadd(yy,datediff(yy,0,getdate()),0) &.A_d+K&
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Ymut]`dX
上面的SQL代码只是一个时间段 ^z?b6kTC
Dateadd(wk,datediff(wk,0,getdate()),-1) !cW rB9
Dateadd(wk,datediff(wk,0,getdate()),6) v rs
就是表示本周时间段. 3[m~-8
下面的SQL的条件部分,就是查询时间段在本周范围内的: @r"\bBi
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) mqSVd^
而在存储过程中 Oa[
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) %|-N{> wKy
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |XyX%5p*