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。 0O-"tP8o
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一、基础 Y0m?ZVt
1、说明:创建数据库 yJ6g{#X4K<
CREATE DATABASE database-name q|r*4={^!*
2、说明:删除数据库 e@/' o/
drop database dbname SMfa(+V I
3、说明:备份sql server A5]yC\*zt
--- 创建 备份数据的 device e<FMeg7n
USE master Z`zLrXPD)
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 4X+I2CD
--- 开始 备份 d>Nh<PqH6
BACKUP DATABASE pubs TO testBack >+>N/`BG
4、说明:创建新表 IS;[oJef
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) G)_Zls2;
根据已有的表创建新表: 1K R4Wq@
A:create table tab_new like tab_old (使用旧表创建新表) <(V~eo
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B:create table tab_new as select col1,col2... from tab_old definition only kLpq{GUv:
5、说明:删除新表 PSX
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drop table tabname JZE@W-2
6、说明:增加一个列 b):aqRwP
Alter table tabname add column col type qZv@ULluc
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。 zE?dQD^OD
7、说明:添加主键: Alter table tabname add primary key(col) 2v#gCou
说明:删除主键: Alter table tabname drop primary key(col) sB^ejH
8、说明:创建索引:create [unique] index idxname on tabname(col....) qElPYN*wF
删除索引:drop index idxname vL^ +X`.td
注:索引是不可更改的,想更改必须删除重新建。 y=[{:
9、说明:创建视图:create view viewname as select statement |zd5P
删除视图:drop view viewname w|*D{`O
10、说明:几个简单的基本的sql语句 {LCKt/Z>P
选择:select * from table1 where 范围 i'^! SEt
插入:insert into table1(field1,field2) values(value1,value2) f|)~_JH
删除:delete from table1 where 范围 vg_PMy\
更新:update table1 set field1=value1 where 范围 x\VP
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8s-X H
排序:select * from table1 order by field1,field2 [desc] `0!%jz=
总数:select count as totalcount from table1 4T
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求和:select sum(field1) as sumvalue from table1 rq}xuSFI
平均:select avg(field1) as avgvalue from table1 gkKNOus
最大:select max(field1) as maxvalue from table1 BW`;QF<
最小:select min(field1) as minvalue from table1 U)Tl<l<
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11、说明:几个高级查询运算词 &!M6{O=~
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A: UNION 运算符 ~C3Ada@4
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。 3*(><<ZC
B: EXCEPT 运算符 yx ;K&>
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。 jR@>~t[}o
C: INTERSECT 运算符 $d,{I8d
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 s'IB{lJ9
注:使用运算词的几个查询结果行必须是一致的。 uss!E!_%,
12、说明:使用外连接 kf9]nIo
A、left outer join: CJs
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 {G<1.
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [qkc6sqo
B:right outer join: (XFF}~>B.
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 +RkXe;q
C:full outer join: K,*-Y)v2W
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 -7%dgY(
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二、提升 pE X Q
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 1&9w]\Ae7l
法一:select * into b from a where 1<>1 P.1Z@HC
法二:select top 0 * into b from a V-X Ty
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) pqju@FD*
insert into b(a, b, c) select d,e,f from b; \YF07L]qs-
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) ,^eOwWV
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 s vS)7]{cU
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. {/>uc,8O
4、说明:子查询(表名1:a 表名2:b) >*n4j:
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 0W+RVp=TL1
5、说明:显示文章、提交人和最后回复时间 [8oX[oP
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \%V !&
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6、说明:外连接查询(表名1:a 表名2:b) S?OCy4dk:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Z/4bxO=m
7、说明:在线视图查询(表名1:a ) %5@>
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select * from (SELECT a,b,c FROM a) T where t.a > 1; :1@jl2,
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ];N/KHeZ
select * from table1 where time between time1 and time2 PpF`0w=1%l
select a,b,c, from table1 where a not between 数值1 and 数值2 LZE9]Gd
9、说明:in 的使用方法 jJ,y+o
select * from table1 where a [not] in ('值1','值2','值4','值6') ,wv>G]v
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9JJ6$cLF
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) s%6L94\t
11、说明:四表联查问题: C^,J6;'
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 ..... x;LO{S4Z
12、说明:日程安排提前五分钟提醒 b5f+q:?{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 -mLu!32I<
13、说明:一条sql 语句搞定数据库分页 roe_H>
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 eW}-UeT
14、说明:前10条记录 sN5Mm8~
select top 10 * form table1 where 范围 +~M.VsX
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.) ?Jgqb3+!o
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) SxcE@WM
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 Rz6kwh=q
(select a from tableA ) except (select a from tableB) except (select a from tableC) -@B6 $XWL
17、说明:随机取出10条数据 TD4
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select top 10 * from tablename order by newid() HIfi18
18、说明:随机选择记录 ^BW8zu@=O
select newid() wgq=9\+&
19、说明:删除重复记录 ejbtdU8N<
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !X-ThKEq
20、说明:列出数据库里所有的表名 ")nKFs5
select name from sysobjects where type='U' %/hokyx
21、说明:列出表里的所有的 R$+"'N6p
select name from syscolumns where id=object_id('TableName') SbsdunW+?
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。 ,Z7Ky*<j
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 Fx)><+-
显示结果: VD =f 'D
type vender pcs P\z1fscnK
电脑 A 1 aQzmobleep
电脑 A 1 {BJH}vV1)
光盘 B 2 ` 1y @c"t
光盘 A 2 |It{L0=U
手机 B 3 !d[]Qt%mA
手机 C 3 ,JPDPI/a
23、说明:初始化表table1 HW"5MZ8E
TRUNCATE TABLE table1 Y ._Om}H
24、说明:选择从10到15的记录 -B-HZ_
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc C]ax}P>BQ
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三、技巧 h///
1、1=1,1=2的使用,在SQL语句组合时用的较多 Mt%Q5^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, h96<9L
如: Qkw_9
if @strWhere !='' _p9 _P g8
begin q 1u_r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >N}+O<Fc
end <xH!
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else 3Gw*K-.
begin C/ ]Bx
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ;$qc@)Uwp
end ?}u][akM
我们可以直接写成 [d>2F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 0$U\H>r
2、收缩数据库 x_/H
--重建索引 <Oy2JjY
DBCC REINDEX aghlYcPg
DBCC INDEXDEFRAG 4=& d{.E
--收缩数据和日志 <\d2)Iv
DBCC SHRINKDB xr!A>q+@i
DBCC SHRINKFILE ygUX ]*m!
3、压缩数据库 I^D*) z
dbcc shrinkdatabase(dbname) 5D3&6DCH
4、转移数据库给新用户以已存在用户权限 M[_Ptqjb
exec sp_change_users_login 'update_one','newname','oldname' |47 2X&e
go [:A">eYI
5、检查备份集 2%`8
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qi8AK(v
6、修复数据库 ogya~/
ALTER DATABASE [dvbbs] SET SINGLE_USER N2u4MI2
GO $ylxl"Y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK (;HO3Z".q$
GO 4(,X.GVY/
ALTER DATABASE [dvbbs] SET MULTI_USER >F/E,U ]
GO hWX4 P
7、日志清除 gDX\ p>7
SET NOCOUNT ON >9<rc[
DECLARE @LogicalFileName sysname, XqcNFSo)
@MaxMinutes INT, Jr>Nc}!U
@NewSize INT ^{E_fQJX
USE tablename -- 要操作的数据库名 f
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 nGTqW/k[+s
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Fg2/rC:_
@NewSize = 1 -- 你想设定的日志文件的大小(M) cn9=wm\\
-- Setup / initialize E6- ~
DECLARE @OriginalSize int &G3$q,`H
SELECT @OriginalSize = size }UG<_bE|
FROM sysfiles HEK?z|Ne
WHERE name = @LogicalFileName s:tWEgZk?
SELECT 'Original Size of ' + db_name() + ' LOG is ' + T%YN(f
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4!?4Tc!X
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' B5;94YIN
FROM sysfiles eYv+tjIF
WHERE name = @LogicalFileName =v{ R(IX%
CREATE TABLE DummyTrans -^rdB6O6j
(DummyColumn char (8000) not null) JNu+e#.Y
DECLARE @Counter INT, dcE(uf
@StartTime DATETIME, `_J>R
@TruncLog VARCHAR(255) t*c_70|@k
SELECT @StartTime = GETDATE(), HLE%f;
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' gM6o~ E
DBCC SHRINKFILE (@LogicalFileName, @NewSize) (W9 K:]}
EXEC (@TruncLog) 7?
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-- Wrap the log if necessary. mVT[:a3
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired l@@qpaH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ) LBbA
AND (@OriginalSize * 8 /1024) > @NewSize L|A1bxt
BEGIN -- Outer loop. K-@cn*6
SELECT @Counter = 0 /j\.~=,_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ` ^z
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BEGIN -- update of`WP
INSERT DummyTrans VALUES ('Fill Log') ]\3<UL
DELETE DummyTrans hXx:D3h
SELECT @Counter = @Counter + 1 a1v?{vu\E
END g{m~TVm'
EXEC (@TruncLog) X(C=O?A
END \Fu(IuD
SELECT 'Final Size of ' + db_name() + ' LOG is ' + JS&;7Z$KX
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 1_G+sDw$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |j$$0N
FROM sysfiles 8:
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WHERE name = @LogicalFileName ~jC$C2A0
DROP TABLE DummyTrans N,ZmGzNP)
SET NOCOUNT OFF Mo4igP
8、说明:更改某个表 mDA1$fj"
exec sp_changeobjectowner 'tablename','dbo' }O6E5YCm
9、存储更改全部表 9;A9Q9Yr
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch !1bATO:x
@OldOwner as NVARCHAR(128), +1Rz +
@NewOwner as NVARCHAR(128) e&9v`8}
AS !@
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DECLARE @Name as NVARCHAR(128) 2W)KfS
DECLARE @Owner as NVARCHAR(128) h<BTu7a`r
DECLARE @OwnerName as NVARCHAR(128) -TyBb]
DECLARE curObject CURSOR FOR {ka={7
select 'Name' = name, YXGxE&!
'Owner' = user_name(uid) 1(Lq9hs`
from sysobjects /8lmNA
where user_name(uid)=@OldOwner `>k7^!Ds
order by name P0-K/_g
OPEN curObject \Iz-<:gA'
FETCH NEXT FROM curObject INTO @Name, @Owner F=;nWQ&
WHILE(@@FETCH_STATUS=0) DM{Z#b]
BEGIN t
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if @Owner=@OldOwner 7t6TB*H
begin H*&!$s.
set @OwnerName = @OldOwner + '.' + rtrim(@Name) }wGy#!CSza
exec sp_changeobjectowner @OwnerName, @NewOwner ESkhCDU
end [iN\R+:
-- select @name,@NewOwner,@OldOwner kg$w<C@#"
FETCH NEXT FROM curObject INTO @Name, @Owner sg_%=;
END 9]a!1
close curObject 0}$R4<"{Y>
deallocate curObject H$xUOqL
GO v+d? #^
10、SQL SERVER中直接循环写入数据 MAgoxq~;V
declare @i int -qB{TA-.\
set @i=1 W)u9VbPk[
while @i<30 } DkdF
begin fvoPV&:
insert into test (userid) values(@i) WAGU|t#."
set @i=@i+1 ET~^P
end E, |OMK#
小记存储过程中经常用到的本周,本月,本年函数 F^7qr
Dateadd(wk,datediff(wk,0,getdate()),-1) s&6/fa
Dateadd(wk,datediff(wk,0,getdate()),6) G}'\
Dateadd(mm,datediff(mm,0,getdate()),0) nD{{/_"'
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]Q{MF- EKj
Dateadd(yy,datediff(yy,0,getdate()),0) 0C0ld!>r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~*RBMHs
上面的SQL代码只是一个时间段 l>@){zxL
Dateadd(wk,datediff(wk,0,getdate()),-1) j.29nJ
Dateadd(wk,datediff(wk,0,getdate()),6) gCW
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就是表示本周时间段. ujbJ&p
下面的SQL的条件部分,就是查询时间段在本周范围内的: ZJ|&t
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) <{k8 K6
而在存储过程中 OJ)XJL
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) S6c>D&Q
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) U5H5QW +