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。 =Sa~\k+
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一、基础 )WmZP3$^TX
1、说明:创建数据库 F3 Y<ZbxT
CREATE DATABASE database-name t2U$m'(A&
2、说明:删除数据库 3;A$<s
drop database dbname nd;O(s;
3、说明:备份sql server kU1 %f
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--- 创建 备份数据的 device *W%'Di
USE master y
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 7PA=)a\
--- 开始 备份 Pj._/$R[/
BACKUP DATABASE pubs TO testBack W8VO)3nmD
4、说明:创建新表 KX=/B=3~
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) H>Ks6V)RL4
根据已有的表创建新表: hg4J2m
A:create table tab_new like tab_old (使用旧表创建新表) V_lGj
B:create table tab_new as select col1,col2... from tab_old definition only cCk1'D|X[e
5、说明:删除新表 hR0]8l|
drop table tabname r.?+gW!C
6、说明:增加一个列 A]#_"fayo
Alter table tabname add column col type }H; ]k-)
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。 XHZLWh"gS
7、说明:添加主键: Alter table tabname add primary key(col) umryA{Ps
说明:删除主键: Alter table tabname drop primary key(col) f}%sO
8、说明:创建索引:create [unique] index idxname on tabname(col....) H(?e&Qkg
删除索引:drop index idxname O'fc/cvh='
注:索引是不可更改的,想更改必须删除重新建。 M&OsRrq
9、说明:创建视图:create view viewname as select statement pLPd[a
删除视图:drop view viewname Yx!n*+ :J
10、说明:几个简单的基本的sql语句 s<,"Hsh^CR
选择:select * from table1 where 范围 jOtzx"/)rE
插入:insert into table1(field1,field2) values(value1,value2) N" ; ^S
删除:delete from table1 where 范围 g4Bg6<;
更新:update table1 set field1=value1 where 范围 PK8V2Ttv
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! GajI\_o
排序:select * from table1 order by field1,field2 [desc] 3}yraX6r!
总数:select count as totalcount from table1 [&Lxz~W][
求和:select sum(field1) as sumvalue from table1 LPMb0F}"5
平均:select avg(field1) as avgvalue from table1 sI$:V7/!
最大:select max(field1) as maxvalue from table1 bje'Oolc
最小:select min(field1) as minvalue from table1 z30= ay1
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11、说明:几个高级查询运算词 *50ZinfoG
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A: UNION 运算符
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UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 m8p4U-*j
B: EXCEPT 运算符 Sw[=S '(l
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 P^ by'b+zI
C: INTERSECT 运算符 HaS[.&\S0
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 uQ-WTz|*
注:使用运算词的几个查询结果行必须是一致的。 95VqaR,
12、说明:使用外连接 r^e-.,+
A、left outer join: '&+Z ,
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 UX?X]ZYVR
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R+C+$?4NG
B:right outer join: -)<JBs>
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。 WGluZhRuT3
C:full outer join: N:5b1TdI,
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。 WI%zr2T
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二、提升 h@EJTAi
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <x ^IwS
法一:select * into b from a where 1<>1 Fv<]mu
法二:select top 0 * into b from a Gl=@>Dc%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) &MBOAHhze
insert into b(a, b, c) select d,e,f from b;
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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) j^:b-:F
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 A-}PpH~.Z
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +ESX.Vel
4、说明:子查询(表名1:a 表名2:b) CRP7U
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) [@jp9D
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5、说明:显示文章、提交人和最后回复时间 @b4b{d5[
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b zR_9D}
6、说明:外连接查询(表名1:a 表名2:b) (gFQK[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;H`=):U
7、说明:在线视图查询(表名1:a ) Ti /;|lP@
select * from (SELECT a,b,c FROM a) T where t.a > 1; @:I\\S@bN
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 uV/)Gb*j
select * from table1 where time between time1 and time2 Uzy;#q
select a,b,c, from table1 where a not between 数值1 and 数值2 *vEU}SxRuv
9、说明:in 的使用方法 xtG)^x!
select * from table1 where a [not] in ('值1','值2','值4','值6') \z<ws&z3`$
10、说明:两张关联表,删除主表中已经在副表中没有的信息 }Z<D^Z~w
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) r@\,VD6J
11、说明:四表联查问题: g4?Q.'dZr
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 ..... DX7Ou%P,mg
12、说明:日程安排提前五分钟提醒 8s\8`2=
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 K#%O3RRs
13、说明:一条sql 语句搞定数据库分页 qFB9,cUqh
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 b6
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14、说明:前10条记录 RRK^~JQI.2
select top 10 * form table1 where 范围 Mp}!+K
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.) Nu>sp,|A
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +F#=`+V
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 2X
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(select a from tableA ) except (select a from tableB) except (select a from tableC) 17?NR\Q
17、说明:随机取出10条数据 7]R6
select top 10 * from tablename order by newid() btJ,dpir
18、说明:随机选择记录 |s)VjS4@
select newid() R;5QD`
19、说明:删除重复记录 wR`w@5,d
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) /r #b
20、说明:列出数据库里所有的表名 U0lqGEZ
select name from sysobjects where type='U' $sB48LJuU'
21、说明:列出表里的所有的 My`josJ`Pb
select name from syscolumns where id=object_id('TableName') iPR!JX
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 :Q0?ub]
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type (Q*2dd>
显示结果: A?%XO
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type vender pcs TW;|G'}$
电脑 A 1 `Pz!SJ|
电脑 A 1 $_%2D3-;D
光盘 B 2 'US8"83
光盘 A 2 TZvBcNi
手机 B 3 &z{dr~
手机 C 3 ~)oWSo5ll
23、说明:初始化表table1 b6rzHnl{
TRUNCATE TABLE table1 HXlr
24、说明:选择从10到15的记录 -;W\f<q]
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc G~Q*:m
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三、技巧 ru(?a~lF8~
1、1=1,1=2的使用,在SQL语句组合时用的较多 q329z>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, L~SrI{aYPf
如: o}j_eHl{
if @strWhere !='' 'Kt4O9=p
begin %Hh &u
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere <
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end Rz])wBv e
else +qu@dU0\`|
begin x _YV{
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `SSP53R(0
end J%O[@jX1
我们可以直接写成 ?[*@T2Ck
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere W}<M?b4tP
2、收缩数据库 |yId6v
--重建索引 * 7zN
DBCC REINDEX N'Z_6A*-
DBCC INDEXDEFRAG c DEe?WS
--收缩数据和日志 \!' {-J
DBCC SHRINKDB ~]i]kU
DBCC SHRINKFILE iYmzk?U
3、压缩数据库 V}Y~z)i0
dbcc shrinkdatabase(dbname) qx#ghcU
4、转移数据库给新用户以已存在用户权限 80R=r
exec sp_change_users_login 'update_one','newname','oldname' +lXdRc`6
go qAuUe=w%p
5、检查备份集 s\3Z?zm8
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' %yS`C"ZQ)
6、修复数据库 [h2p8i'o
ALTER DATABASE [dvbbs] SET SINGLE_USER o#KPrW`XJ/
GO 8m13M5r
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK l yLK$B?/
GO )=SYJ-ta<
ALTER DATABASE [dvbbs] SET MULTI_USER }X W#?l
GO @zVBn~=i
7、日志清除 "8C(_z+]K`
SET NOCOUNT ON k*UR#z(I
DECLARE @LogicalFileName sysname, :BrnRW64
@MaxMinutes INT, %l]rQjV-
@NewSize INT `)gkkZ$)j
USE tablename -- 要操作的数据库名 W0r5D9k
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 * zJiii
@MaxMinutes = 10, -- Limit on time allowed to wrap log. M%Kx{*aw&
@NewSize = 1 -- 你想设定的日志文件的大小(M) 'piF_5(@
-- Setup / initialize Hhce:E@K
DECLARE @OriginalSize int b$$L]$q2
SELECT @OriginalSize = size *Tlws
FROM sysfiles /n<Ncf
WHERE name = @LogicalFileName 9O0
SELECT 'Original Size of ' + db_name() + ' LOG is ' + j{Qbzczy,
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + jW+VUF-t
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' }1^tK(Am
FROM sysfiles aGzdur
WHERE name = @LogicalFileName VHXR)}
CREATE TABLE DummyTrans $4ZDT]n
(DummyColumn char (8000) not null) m= beB\=
DECLARE @Counter INT, _QtQPK\+
@StartTime DATETIME, ;wYwiSVd
@TruncLog VARCHAR(255) .tHv4.ob
SELECT @StartTime = GETDATE(), q}76aa0e
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' E )Zd{9A5)
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Aaw:B?4)
EXEC (@TruncLog) fU){]YP
-- Wrap the log if necessary. {u[K
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _R!!4Hp<Q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) %onAlf<$:^
AND (@OriginalSize * 8 /1024) > @NewSize uhN(`E@
BEGIN -- Outer loop. b3HTCO-,fC
SELECT @Counter = 0 x.4)p6
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `
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BEGIN -- update @0@'6J04
INSERT DummyTrans VALUES ('Fill Log') W2o8Fu
DELETE DummyTrans `efH(
SELECT @Counter = @Counter + 1 hcqmjqJ
END %+OPas8C
EXEC (@TruncLog) cK}
END 6;=wuoJi
SELECT 'Final Size of ' + db_name() + ' LOG is ' + mYs->mg1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + G QB^
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' HI`A;G]
FROM sysfiles ~Sem_U`G
WHERE name = @LogicalFileName ''
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DROP TABLE DummyTrans 1J%qbh
SET NOCOUNT OFF :R?| 2l
8、说明:更改某个表 @BQBNGR 1
exec sp_changeobjectowner 'tablename','dbo' JMe[
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9、存储更改全部表 fm2M i~}0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), pUEok +
@NewOwner as NVARCHAR(128) W&re;?Z{ke
AS Q9'p3"yoE
DECLARE @Name as NVARCHAR(128) $4~}_phi
DECLARE @Owner as NVARCHAR(128) a_fW{;}[
DECLARE @OwnerName as NVARCHAR(128) LyPBFo[?
DECLARE curObject CURSOR FOR ?Dp^dR
select 'Name' = name, s$y#Ufz
'Owner' = user_name(uid) /v ;Kb|e
from sysobjects a0W\?
where user_name(uid)=@OldOwner arH\QPaka'
order by name J,M5<s[Xqt
OPEN curObject oP`M\KXau
FETCH NEXT FROM curObject INTO @Name, @Owner o%JIJ7M
WHILE(@@FETCH_STATUS=0) (w:ACJ[[
BEGIN O?J:+L(
if @Owner=@OldOwner M{kh=b)V
begin .nY6[2am
set @OwnerName = @OldOwner + '.' + rtrim(@Name) g4qdm{BL
exec sp_changeobjectowner @OwnerName, @NewOwner tS\NO@E_Jh
end Y,Zv0-"
-- select @name,@NewOwner,@OldOwner 9PfU'm|h
FETCH NEXT FROM curObject INTO @Name, @Owner 1kw4'#J8
END (c|qX-%rC
close curObject O)Dw<j)
deallocate curObject $U.'K!B
GO >u#VHaB
10、SQL SERVER中直接循环写入数据 r%mTOLef
declare @i int \B ^sJ[n
set @i=1 G+^$JN=
while @i<30 |Ie`L("
begin hBSJEP
insert into test (userid) values(@i) e;u8G/
set @i=@i+1 4W-+k
end 1E_Ui1 [
小记存储过程中经常用到的本周,本月,本年函数 "@?kxRn!
Dateadd(wk,datediff(wk,0,getdate()),-1) Nn7@+g)
Dateadd(wk,datediff(wk,0,getdate()),6) y8n1IZ*#SZ
Dateadd(mm,datediff(mm,0,getdate()),0) A|OC?NZY
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) b1^Yxe#L
Dateadd(yy,datediff(yy,0,getdate()),0) 29DWRJU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ;+KgujfU
上面的SQL代码只是一个时间段 }? '9L:
Dateadd(wk,datediff(wk,0,getdate()),-1) =v=!x
Dateadd(wk,datediff(wk,0,getdate()),6) R2ZQBwB
就是表示本周时间段. &_hCs![
下面的SQL的条件部分,就是查询时间段在本周范围内的: 1>{-wL4rc
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) __%E!*m"<_
而在存储过程中 \k-juF80
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) iC2nHZ*,
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) z(68^-V=: