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。 yF1p^>*ak&
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一、基础 %m|1LI(
1、说明:创建数据库 [Zzztn+
CREATE DATABASE database-name [7 NO !^
2、说明:删除数据库 QKhGEW~G
drop database dbname /,~g"y.;,
3、说明:备份sql server +N'&6z0Wf
--- 创建 备份数据的 device Z:^ S-h
USE master d\zUtcJwC
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' KT17I&:
--- 开始 备份 |9p0"#4u
BACKUP DATABASE pubs TO testBack CSz+cS
4、说明:创建新表 ]re}EB\Rs
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) VGc.yM)&
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根据已有的表创建新表: bcT'!:
A:create table tab_new like tab_old (使用旧表创建新表) Xoha.6$l5
B:create table tab_new as select col1,col2... from tab_old definition only !R@jbM
5、说明:删除新表 drvrj~o:
drop table tabname m4yWhUi(o
6、说明:增加一个列 KzJJ@D*4M]
Alter table tabname add column col type Q- w_@~
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。 /`0>U
7、说明:添加主键: Alter table tabname add primary key(col) >UV}^OO
说明:删除主键: Alter table tabname drop primary key(col) KT7R0 v
8、说明:创建索引:create [unique] index idxname on tabname(col....) .*X=["
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删除索引:drop index idxname T%;NW|mH&
注:索引是不可更改的,想更改必须删除重新建。 z.+%{_pe
9、说明:创建视图:create view viewname as select statement 1f'msy/
删除视图:drop view viewname 6 !N2B[9
10、说明:几个简单的基本的sql语句 &C)97E
选择:select * from table1 where 范围 bAy\Sr
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插入:insert into table1(field1,field2) values(value1,value2) mD|Q+~=|e
删除:delete from table1 where 范围 +zXcTT[V
更新:update table1 set field1=value1 where 范围 nrX+ '
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ;]bW
排序:select * from table1 order by field1,field2 [desc] B79~-,Yh
总数:select count as totalcount from table1 KXpbee
求和:select sum(field1) as sumvalue from table1 o,S(;6pDJ
平均:select avg(field1) as avgvalue from table1 $My~sN8
最大:select max(field1) as maxvalue from table1 t*dq*(3"c
最小:select min(field1) as minvalue from table1 a 7=lZZ?
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11、说明:几个高级查询运算词 >;R7r|^k
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A: UNION 运算符 G}LV"0?
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 b|;h$otC
B: EXCEPT 运算符 NqveL<r`
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。 {wgq>cb
C: INTERSECT 运算符 O1wo
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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。 TB= _r(:l+
注:使用运算词的几个查询结果行必须是一致的。 Y\+LBbB8
12、说明:使用外连接 UJ(UzKq8
A、left outer join: vp9wRGd
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。 tR2%oT>h
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 l2YA/9.
B:right outer join: ,?HM5c{'[Y
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。 ) jt?X}
C:full outer join: |.$7.8g
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 MOay^{u
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二、提升 B|8|f(tsSa
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) HLdHyK/S
法一:select * into b from a where 1<>1 nJ/}b/A{
法二:select top 0 * into b from a c-!3wvt)
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) B(5>H2
insert into b(a, b, c) select d,e,f from b; zL3zvOhu}
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) SoHaGQox
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 k*!iUz{]
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 6eA)d#
4、说明:子查询(表名1:a 表名2:b) I6gduvkXi4
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) YpRhl(|
5、说明:显示文章、提交人和最后回复时间 jSRi
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b UX<)hvKj
6、说明:外连接查询(表名1:a 表名2:b) pf+VYZ#)
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c SqdI($F\:
7、说明:在线视图查询(表名1:a ) -M_>]ubG
select * from (SELECT a,b,c FROM a) T where t.a > 1; D;jbZ9
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 s:(z;cj/
select * from table1 where time between time1 and time2 k#7A@Vb
select a,b,c, from table1 where a not between 数值1 and 数值2 euW
9、说明:in 的使用方法 SJlE!MK
select * from table1 where a [not] in ('值1','值2','值4','值6') +_u~Np
10、说明:两张关联表,删除主表中已经在副表中没有的信息 [hk/Rp7{
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %Pj}
11、说明:四表联查问题: ~*UY[!+4^=
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 ..... ao[yHcAs
12、说明:日程安排提前五分钟提醒 g}uSIv^
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^]~!:Ej0
13、说明:一条sql 语句搞定数据库分页 B#35)QI
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 $$< I}eMd>
14、说明:前10条记录 ):}A Quy]
select top 10 * form table1 where 范围 j)Kd'Va
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.) [1ClZ~f
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) %tZrP$DQ
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 X#K;(.},h
(select a from tableA ) except (select a from tableB) except (select a from tableC) 45$aq~%as
17、说明:随机取出10条数据 q)KOI`A
select top 10 * from tablename order by newid() l4(FM}0X5}
18、说明:随机选择记录 &-X51O C
select newid() 8xG"hJR
19、说明:删除重复记录 [Fv,`*/sm
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) i}i>ho-8
20、说明:列出数据库里所有的表名 +P,ic*Kq*
select name from sysobjects where type='U' 4x3 _8/=
21、说明:列出表里的所有的 a2kAZCQ
select name from syscolumns where id=object_id('TableName') c&{= aIe w
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。 Yx,7e(AI`
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 G007[|
显示结果: <h}x7y?
type vender pcs (0.JoeA`y
电脑 A 1 R*XZPzg%
电脑 A 1 0IA'5)
光盘 B 2 L/I ]
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光盘 A 2 5J1a8RBR
手机 B 3 +Ar4X-A{y
手机 C 3 c': 4e)
23、说明:初始化表table1 m/(/!MVy
TRUNCATE TABLE table1 a/3'!} &e
24、说明:选择从10到15的记录 inZ0iU9dy
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc `D$^SHfyz
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三、技巧 Sm?|,C3V
1、1=1,1=2的使用,在SQL语句组合时用的较多 HDKY7Yr
"where 1=1" 是表示选择全部 "where 1=2"全部不选, VB T66kV
如: W
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if @strWhere !='' q5@Nd3~h
begin MpvGF7H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _@gg,2
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end _x#y
else TXS`ey
begin 3>73s}3
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]` A*7
end VM\\.L
我们可以直接写成 n<<arO"cv
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ?~#[cx
2、收缩数据库 Z7[S698
--重建索引 J^%E$s
DBCC REINDEX ~Fl\c-
DBCC INDEXDEFRAG D/%v/mpj$
--收缩数据和日志 ~ _tK.m3
DBCC SHRINKDB }J92TV
DBCC SHRINKFILE `T ^0&#
3、压缩数据库 {4f%UnSz(
dbcc shrinkdatabase(dbname) Qu7ML]e?z
4、转移数据库给新用户以已存在用户权限 es\
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exec sp_change_users_login 'update_one','newname','oldname' |TkicgeS
go pY&dw4V
5、检查备份集 ?hR0
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -vk/z+-^!
6、修复数据库 ,# .12Q!
ALTER DATABASE [dvbbs] SET SINGLE_USER UX.rzYM&T
GO KxeqQ@
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 6c/0OM#
GO riaL[4c
ALTER DATABASE [dvbbs] SET MULTI_USER f~TkU\Rh
GO $=^}J6
7、日志清除 /h`gQyGuY
SET NOCOUNT ON
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DECLARE @LogicalFileName sysname, E?|NYu#I6
@MaxMinutes INT, X%fLV(
@NewSize INT !8W0XUqh+
USE tablename -- 要操作的数据库名 CRrEs
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 IB 4L(n1
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >9#) obw
@NewSize = 1 -- 你想设定的日志文件的大小(M) =?wDQ:
-- Setup / initialize px+]/P<dX
DECLARE @OriginalSize int ,@f |t&
SELECT @OriginalSize = size W$J.B!O
FROM sysfiles h^`@%g9 S
WHERE name = @LogicalFileName MBKF8b'k
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 0b8=94a{>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + /Dt:4{aTOC
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' i.?rom
FROM sysfiles wN/v-^2
WHERE name = @LogicalFileName DAORfFG74
CREATE TABLE DummyTrans {.o4U0+
(DummyColumn char (8000) not null) A=e1uBGA
DECLARE @Counter INT, ^gpd '*b
@StartTime DATETIME, xS+xUi
@TruncLog VARCHAR(255) Fl{~#]
SELECT @StartTime = GETDATE(), xy$aFPH!-
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' a\Gd;C ^`
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Nl%5OBm
EXEC (@TruncLog) 5INw#1~
-- Wrap the log if necessary. +>[zn
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;'Z"CbS+
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ?A r}QN
AND (@OriginalSize * 8 /1024) > @NewSize 42-T&7k
BEGIN -- Outer loop. BePb8
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SELECT @Counter = 0 Dvl\o;
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Nt?=0X|M
BEGIN -- update ]*U; }
INSERT DummyTrans VALUES ('Fill Log') Q`Pe4CrWvu
DELETE DummyTrans HJpx,NU'
SELECT @Counter = @Counter + 1 (dO0`wfM
END yGC
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EXEC (@TruncLog) }NdLd!
END |o(te
SELECT 'Final Size of ' + db_name() + ' LOG is ' + DZb0'+jQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + aM,g@'.=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' JnnxXj30,
FROM sysfiles aYHs35
WHERE name = @LogicalFileName }S13]Kk?=
DROP TABLE DummyTrans 00y(E@~
SET NOCOUNT OFF VAyAXN~
8、说明:更改某个表 5bI4'
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exec sp_changeobjectowner 'tablename','dbo' 4 EA$<n(A-
9、存储更改全部表 7*Zm{r@u
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch kXUJlLod
@OldOwner as NVARCHAR(128), }v_|N"@
@NewOwner as NVARCHAR(128) ^%g8OP
AS \RFA?PuY
DECLARE @Name as NVARCHAR(128) d0zp89BEn
DECLARE @Owner as NVARCHAR(128) a_b+RMy
DECLARE @OwnerName as NVARCHAR(128) PG|Zu3[
DECLARE curObject CURSOR FOR 78?{;iNv
select 'Name' = name, u3UN
'Owner' = user_name(uid) =i7CF3
from sysobjects $~
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where user_name(uid)=@OldOwner 7suT26C
order by name pXh`o20I
OPEN curObject JEZ0O&_R
FETCH NEXT FROM curObject INTO @Name, @Owner 3(.Y>er%U
WHILE(@@FETCH_STATUS=0) 92b}N|u
BEGIN Jk{v(W#
if @Owner=@OldOwner A
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begin H,j_2JOY=
set @OwnerName = @OldOwner + '.' + rtrim(@Name) \]\GDpu[
exec sp_changeobjectowner @OwnerName, @NewOwner ;\j'~AyCn
end Lc-WfzT
-- select @name,@NewOwner,@OldOwner XJq]l6a:
FETCH NEXT FROM curObject INTO @Name, @Owner G1ruF8
END 0Q
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close curObject u-V(
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deallocate curObject X~\O]
GO 5pHv5e
10、SQL SERVER中直接循环写入数据 _Vc4F_
declare @i int 8S[bt@v
set @i=1 *$1F|G
while @i<30 cN\_1
begin c+whpQ=01
insert into test (userid) values(@i) wp:Zur5Y
set @i=@i+1 #AO}JP
end "Z dI~
小记存储过程中经常用到的本周,本月,本年函数 TKEcbGhy
Dateadd(wk,datediff(wk,0,getdate()),-1) YXdo&'Q<qX
Dateadd(wk,datediff(wk,0,getdate()),6) ?D_}',Wx
Dateadd(mm,datediff(mm,0,getdate()),0) :."+&gb
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) yy3`E}vX7
Dateadd(yy,datediff(yy,0,getdate()),0) e\*(F3r
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) '?X?'_3
上面的SQL代码只是一个时间段 >+:cTQ|q
Dateadd(wk,datediff(wk,0,getdate()),-1) u:wijkx
Dateadd(wk,datediff(wk,0,getdate()),6)
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就是表示本周时间段. 4"^W/Zo
下面的SQL的条件部分,就是查询时间段在本周范围内的: X@)'E9g5:
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Sj8fo^K50
而在存储过程中 aan(69=jz
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) p}X *HJq$
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Zu2
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