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。 cwV]!=RtO
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一、基础 xooY'El*#
1、说明:创建数据库 yUPIY:0
CREATE DATABASE database-name jjM{]
2、说明:删除数据库 mXUYQ82
drop database dbname f3|@|'
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3、说明:备份sql server B^%1Rpcn
--- 创建 备份数据的 device -+t]15
USE master +/D>|loRC
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' >3u]OSb
--- 开始 备份 Dz./w
BACKUP DATABASE pubs TO testBack TE )gVE]
4、说明:创建新表 `mT$s,:h
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) lgpW@g
根据已有的表创建新表: _bD/D!|
A:create table tab_new like tab_old (使用旧表创建新表) ~afg)[(
B:create table tab_new as select col1,col2... from tab_old definition only q$G,KRy/
5、说明:删除新表 G^"Vo x4
drop table tabname KN"S?i]X
6、说明:增加一个列 T;L>P[hNn
Alter table tabname add column col type wM_c48|d
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。 hXGwP4
7、说明:添加主键: Alter table tabname add primary key(col) *-s,.
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说明:删除主键: Alter table tabname drop primary key(col) OiDhJ
8、说明:创建索引:create [unique] index idxname on tabname(col....) 8>/Q1(q0
删除索引:drop index idxname #P#-xz
注:索引是不可更改的,想更改必须删除重新建。 b|zg<
9、说明:创建视图:create view viewname as select statement Z!0]/ mCE8
删除视图:drop view viewname lcV<MDS
10、说明:几个简单的基本的sql语句 ET];%~ ^
选择:select * from table1 where 范围 &uUo3qXQ5l
插入:insert into table1(field1,field2) values(value1,value2) >yJ9U,Y
删除:delete from table1 where 范围 dz>;<&2Z
更新:update table1 set field1=value1 where 范围 a}Sd W
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! PA w-6;
排序:select * from table1 order by field1,field2 [desc] _7DkS}NJs
总数:select count as totalcount from table1 CQ;]J=|<_
求和:select sum(field1) as sumvalue from table1 W(RF n`g\
平均:select avg(field1) as avgvalue from table1 Xtq{%
最大:select max(field1) as maxvalue from table1 ?X?&~3iD%
最小:select min(field1) as minvalue from table1 (6v(9p
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11、说明:几个高级查询运算词 zY+Fl~$S
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A: UNION 运算符 DP/J(>eG
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 P'MY[&|mM'
B: EXCEPT 运算符 }bU8G '
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 /MQU
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C: INTERSECT 运算符 VDB;%U*D
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 T!W~n
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注:使用运算词的几个查询结果行必须是一致的。 sS
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12、说明:使用外连接 aAu>Tn86D.
A、left outer join: 8vk..!7n}
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ,7,g%?_P
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c MzIq"3
B:right outer join: e4OeoQ@ >
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 juBw5U<
C:full outer join: ;d$qc<2uA
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。 VGL#!4wK
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二、提升 FZiW|G
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) A|}l)!%
法一:select * into b from a where 1<>1 '2zL.:~
法二:select top 0 * into b from a i~J;G#b
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) OPBt$Ki
insert into b(a, b, c) select d,e,f from b; UueD(T;p
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) B~'MBBD"
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 0:KE@=
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. e$c?}3E!z
4、说明:子查询(表名1:a 表名2:b) M9!AIHq4
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) {J/I-=CmML
5、说明:显示文章、提交人和最后回复时间 6{d6s#|%
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b f^e6<5gdf
6、说明:外连接查询(表名1:a 表名2:b) 4\.V
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c aKF*FFX
7、说明:在线视图查询(表名1:a ) Q-rL$%~='
select * from (SELECT a,b,c FROM a) T where t.a > 1; Y<\^7\[x
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 'cDx{?
select * from table1 where time between time1 and time2 zBf-8]"^
select a,b,c, from table1 where a not between 数值1 and 数值2 !e#xx]v3
9、说明:in 的使用方法 ihT~xt
select * from table1 where a [not] in ('值1','值2','值4','值6') URcR
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Uh.Zi3X6}6
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) !k$}Kj)I
11、说明:四表联查问题: y%]8'q$
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 ..... a=GM[{og
12、说明:日程安排提前五分钟提醒 "%8A:^1
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 B6Ej{q^k,
13、说明:一条sql 语句搞定数据库分页 ~fz[x 9\
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 $N$ FtpB
14、说明:前10条记录 1-I
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select top 10 * form table1 where 范围 j*T]HaM
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.) (\puf+
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [-*F"}D,
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 *:ro
(select a from tableA ) except (select a from tableB) except (select a from tableC) AV&yoag1
17、说明:随机取出10条数据 jn9 ShF
select top 10 * from tablename order by newid() ~c{:DM
18、说明:随机选择记录 cd;NpN
select newid() SN+S6
19、说明:删除重复记录 BdbJ< Is
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %>Xr5<$:&
20、说明:列出数据库里所有的表名 -U2mfW
select name from sysobjects where type='U' sPNfbCOz
21、说明:列出表里的所有的 47 u@4"M
select name from syscolumns where id=object_id('TableName') E(<LvMiCa
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 +V v+K(lh$
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 ZeasYSo4P
显示结果: $7I]`Jt
type vender pcs _8K%`6!"Z
电脑 A 1 sc`"P-J+vp
电脑 A 1 kR.wOJ7'
光盘 B 2 *.y' (tj[
光盘 A 2 PX".Km p.
手机 B 3 ApPy]IdwX
手机 C 3 go)p%}s
23、说明:初始化表table1 D_|B2gdZY
TRUNCATE TABLE table1 hQJWKAf,/
24、说明:选择从10到15的记录 FYPz 4K
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc E(+T*
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三、技巧 `0BdMKjA
1、1=1,1=2的使用,在SQL语句组合时用的较多 a
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, ^[h2% c$
如: @%i>XAe#0
if @strWhere !='' (0*v*kYdL+
begin nYv#4*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ]>:^d%n,}
end ;np_%?is
else <Mgf]v.QS
begin ~] =?b)B
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ((3t:
end [h}K$q
我们可以直接写成 vW.%[]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %u]6KrG18b
2、收缩数据库 #t71U a
--重建索引 EHf)^]Z
DBCC REINDEX sV0Z
DBCC INDEXDEFRAG #!!AbuhzK{
--收缩数据和日志 >.dHt\
DBCC SHRINKDB 4E"d /
DBCC SHRINKFILE c]Unbm^w
3、压缩数据库 O OlTrLL
dbcc shrinkdatabase(dbname) +!&$SNLh(
4、转移数据库给新用户以已存在用户权限 }6~)bLzI}
exec sp_change_users_login 'update_one','newname','oldname' M1=_^f=&.
go zi!#\s^
5、检查备份集 t/:w1rw
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' XK 3]AYH
6、修复数据库 <GW R7rUH
ALTER DATABASE [dvbbs] SET SINGLE_USER P!+v:'P5f
GO okBE|g
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6c\DJD
GO < tQc_
ALTER DATABASE [dvbbs] SET MULTI_USER x72G^`Wv
GO ?M&4pO&Y
7、日志清除 nlfPg-78B+
SET NOCOUNT ON ~"mj;5Id
DECLARE @LogicalFileName sysname, NM L|"R;
@MaxMinutes INT, DA <ynBQ
@NewSize INT wkT;a&_
USE tablename -- 要操作的数据库名 J9@}DB
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5gNLO\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. IhW7^(p\
@NewSize = 1 -- 你想设定的日志文件的大小(M) \y*j4 0
-- Setup / initialize Y$8; Gm<)
DECLARE @OriginalSize int N~g%wf@w
SELECT @OriginalSize = size ?:}Pa<D&K
FROM sysfiles _@prmSc
WHERE name = @LogicalFileName /_OOPt=G
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Zd<[=%d
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + A^pW]r=Xtk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' W(k:Pl#
FROM sysfiles k/#M<z
WHERE name = @LogicalFileName ]V<"(?,K
CREATE TABLE DummyTrans :o\5K2]:
(DummyColumn char (8000) not null) 3_J>y
DECLARE @Counter INT, +Jw{qQR/*
@StartTime DATETIME, i| xt f
@TruncLog VARCHAR(255) aF])"9
SELECT @StartTime = GETDATE(), 6GOg_P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;:_(7|
DBCC SHRINKFILE (@LogicalFileName, @NewSize) wW()Zy0)
EXEC (@TruncLog) xKW"X
-- Wrap the log if necessary. :Y.e[@!1x
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ~L){O*Z
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) TSXTc'
AND (@OriginalSize * 8 /1024) > @NewSize A9n41,h
BEGIN -- Outer loop. Ygx,t|?7
SELECT @Counter = 0 4$i} Xk#3
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) "
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BEGIN -- update LVmY=d>
INSERT DummyTrans VALUES ('Fill Log') !Zj#.6c9
DELETE DummyTrans 5DSuUEvWcL
SELECT @Counter = @Counter + 1 0#=W#Jl>
END &|z|SY]DL
EXEC (@TruncLog) _?Ckq
END HXP;0B%4
SELECT 'Final Size of ' + db_name() + ' LOG is ' + c! ~T2t
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + e?vj+ZlS$f
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' i puo}
FROM sysfiles WY.5K
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WHERE name = @LogicalFileName U3VT*nj'
DROP TABLE DummyTrans V2QW\2@$
SET NOCOUNT OFF JX&~y.F
8、说明:更改某个表 ;Xh5oB\)W
exec sp_changeobjectowner 'tablename','dbo' Oo/8Y
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9、存储更改全部表 "3ug}k
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch =AzOnXW:S
@OldOwner as NVARCHAR(128), 5Jd`
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@NewOwner as NVARCHAR(128) ;*`_#Rn#
AS -R74/GBg
DECLARE @Name as NVARCHAR(128) OequU'j
DECLARE @Owner as NVARCHAR(128) )]}$
DECLARE @OwnerName as NVARCHAR(128) t[ q3{-
DECLARE curObject CURSOR FOR h&$Py
select 'Name' = name, 7V/Zr
'Owner' = user_name(uid) I}ndRDz[
from sysobjects HSql)iT
where user_name(uid)=@OldOwner &z QWIv
order by name l]u7.~b
OPEN curObject Cn/q=
FETCH NEXT FROM curObject INTO @Name, @Owner 7yUvL8p-
WHILE(@@FETCH_STATUS=0) xZg7Jg
BEGIN @|'Z@>!/pV
if @Owner=@OldOwner 'v+96b/;
begin /=-h:0{M
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 8'%+G
exec sp_changeobjectowner @OwnerName, @NewOwner 'rh\CA/}D
end m>O2t-
-- select @name,@NewOwner,@OldOwner ,L~snR'w
FETCH NEXT FROM curObject INTO @Name, @Owner >E~~7Yal
END g6`.qyVfz'
close curObject oo'iwq-\
deallocate curObject |} 9GHjG
GO qAbd xd[
10、SQL SERVER中直接循环写入数据 -rRz@Cr
declare @i int +ruj
set @i=1 Ss+F9J
while @i<30 LiF.w:}
begin ^W k0*.wg
insert into test (userid) values(@i) R1~7F{FW
set @i=@i+1 .:SfMr;G
end =3pD:L
小记存储过程中经常用到的本周,本月,本年函数 P1e5uJkd
Dateadd(wk,datediff(wk,0,getdate()),-1) ~"\P~cg0J
Dateadd(wk,datediff(wk,0,getdate()),6) Upu%.[7
Dateadd(mm,datediff(mm,0,getdate()),0) /:^tc/5U]
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) h4h d<,
Dateadd(yy,datediff(yy,0,getdate()),0) 0x6@{0
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <%(f9j
上面的SQL代码只是一个时间段 7%X+O8
Dateadd(wk,datediff(wk,0,getdate()),-1) P0Aas)!
Dateadd(wk,datediff(wk,0,getdate()),6) 83X/"2-K
就是表示本周时间段. 75PS^5T,
下面的SQL的条件部分,就是查询时间段在本周范围内的: ={OCa1
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) KM E XT$p
而在存储过程中 gMCy$+?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) a3*.,%d
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) i /C'0