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。 &}WSfZ0{
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一、基础 u >x2
1、说明:创建数据库 R]dc(D
CREATE DATABASE database-name
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2、说明:删除数据库 A\:M}D-(
drop database dbname LGK}oL'
3、说明:备份sql server xZ .:H&0G
--- 创建 备份数据的 device zk?lNs
USE master sD
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' &iTsuA/7
--- 开始 备份 rkVZP!7!
BACKUP DATABASE pubs TO testBack F4*f_lP
4、说明:创建新表 9K)2OX;$w
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) MYu-[Hg
根据已有的表创建新表: %
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A:create table tab_new like tab_old (使用旧表创建新表) Rzz*[H
B:create table tab_new as select col1,col2... from tab_old definition only Da.v yp
5、说明:删除新表
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drop table tabname tP`,Egf"g
6、说明:增加一个列 >LLFe~9`g
Alter table tabname add column col type h)sc-e
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。 G'! Hc6OZ
7、说明:添加主键: Alter table tabname add primary key(col) w(VH>t
说明:删除主键: Alter table tabname drop primary key(col) 7p|Pv;wp|
8、说明:创建索引:create [unique] index idxname on tabname(col....) y2)~ljR
删除索引:drop index idxname /@q_`tU
注:索引是不可更改的,想更改必须删除重新建。 $L(,q!DvH
9、说明:创建视图:create view viewname as select statement T. {P}#'|
删除视图:drop view viewname }V09tK/M
10、说明:几个简单的基本的sql语句 WFTTBUoH
选择:select * from table1 where 范围 *5wb8[
插入:insert into table1(field1,field2) values(value1,value2) S#jE1 EN
删除:delete from table1 where 范围 9n1O@~
更新:update table1 set field1=value1 where 范围 V<1dA\I"
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! \SyfEcSf2v
排序:select * from table1 order by field1,field2 [desc] nlh%O@,
总数:select count as totalcount from table1 ?'^xO:
求和:select sum(field1) as sumvalue from table1 7&2xUcsz)
平均:select avg(field1) as avgvalue from table1 Dzb@H$BQ7
最大:select max(field1) as maxvalue from table1 S);bcowf_
最小:select min(field1) as minvalue from table1 >QCVsX>~
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11、说明:几个高级查询运算词 `g3H;E
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A: UNION 运算符 RxcX\:
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。 s(-$|f+s
B: EXCEPT 运算符 x-cg df
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。 L_Om<LO2
C: INTERSECT 运算符 5s8k^n"A
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。 fAXF_wj
注:使用运算词的几个查询结果行必须是一致的。 g+U6E6}1
12、说明:使用外连接 @r=O~x
A、left outer join: 64Q{YuI
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。 rcAx3AK.
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 FK>8(M/
B:right outer join: TtlZum\
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。 7h0LR7
C:full outer join: c.r]w
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。 Ee^2stc-
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二、提升
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0rooL<~fa
法一:select * into b from a where 1<>1 _>0I9.[5
法二:select top 0 * into b from a KftZ^mk+p
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) uK1DC i
insert into b(a, b, c) select d,e,f from b; .*i.Z
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) l.El3+
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (6!W8x7
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !np-Jmi
4、说明:子查询(表名1:a 表名2:b) L~=h?C<
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) c#Y/?F2p
5、说明:显示文章、提交人和最后回复时间 #,lJ>mTe4
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b [s"xOP9R
6、说明:外连接查询(表名1:a 表名2:b) AfB,`l`k
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c s&TPG0W
7、说明:在线视图查询(表名1:a ) AKu]c-
select * from (SELECT a,b,c FROM a) T where t.a > 1; *7FtEk/l
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 Gu-6~^Km9
select * from table1 where time between time1 and time2 W:'H&`0
select a,b,c, from table1 where a not between 数值1 and 数值2 G*JasHFs
9、说明:in 的使用方法 ^,*!Qk<c
select * from table1 where a [not] in ('值1','值2','值4','值6') 67?O}~jbG
10、说明:两张关联表,删除主表中已经在副表中没有的信息 V 9bn
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) lXjhT
11、说明:四表联查问题: 0M-=3 T
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 ..... 7a\at)q/y
12、说明:日程安排提前五分钟提醒 )lwxFP;
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 bW-9YXj%
13、说明:一条sql 语句搞定数据库分页 xim'TVwvC
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 plN:QS$
14、说明:前10条记录 lp+Uox
select top 10 * form table1 where 范围 }fU"s"
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.) Lk#8G>U
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "V'<dn
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
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(select a from tableA ) except (select a from tableB) except (select a from tableC) *:}9(8d
17、说明:随机取出10条数据 K!g!tA$
select top 10 * from tablename order by newid() Cj'XL}
18、说明:随机选择记录 zsOOx%
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select newid() b*Sw")#
19、说明:删除重复记录 n%X5TJE
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 9(eTCe-~6
20、说明:列出数据库里所有的表名 +6-_9qRq
select name from sysobjects where type='U' =jz [}5
21、说明:列出表里的所有的 )jm!bR`
select name from syscolumns where id=object_id('TableName') N.(wR
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。 -Ph"#R&
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 bS7%%8C
显示结果: @?e+;Sx
type vender pcs k}18
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电脑 A 1 B:oE&Ahh{
电脑 A 1 K-<<s
光盘 B 2 #:[^T,YD0
光盘 A 2 q|h#J}\
手机 B 3 x`n7D
手机 C 3 +@G#Z3;l!
23、说明:初始化表table1 (}*1,N!#
TRUNCATE TABLE table1 M$,4B
24、说明:选择从10到15的记录 JP{Y Q:NF
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ZW>iq M^9
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三、技巧 v-(dh5e`
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1、1=1,1=2的使用,在SQL语句组合时用的较多 PJ-g.0q
"where 1=1" 是表示选择全部 "where 1=2"全部不选, uidoz
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如: n~_;tO
if @strWhere !='' 6 H{G$[2
begin nOTe 3?i>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere f0M5^
end <*_DC)&79
else 4m1@lnjp
begin xlIVLv6dO
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' dj-/%MU
end Q{=DLm`
我们可以直接写成 R/EpfYOX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere JIatRc?g
2、收缩数据库 Fa0Fl}L
--重建索引 Fe L !%z
DBCC REINDEX s+0n0C
DBCC INDEXDEFRAG F rd>+
--收缩数据和日志 >lkjoEVQ
DBCC SHRINKDB 2=,O)g
DBCC SHRINKFILE Fe1^9ja
3、压缩数据库 hm,H3pN
dbcc shrinkdatabase(dbname) <I 0 EjV
4、转移数据库给新用户以已存在用户权限 <g$b M;6%
exec sp_change_users_login 'update_one','newname','oldname' thLx!t
go z?<Xx?Kk
5、检查备份集 a! gj_
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' &0x;60b
6、修复数据库 VV-%AS6;
ALTER DATABASE [dvbbs] SET SINGLE_USER HC!5AJ&+}v
GO q~. .Z Y`7
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ;q?WU>c{?
GO p}]K0F!
ALTER DATABASE [dvbbs] SET MULTI_USER 0u}+n+\g
GO %6Y\4Fe
7、日志清除 M#}k@
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SET NOCOUNT ON "N3!!3
DECLARE @LogicalFileName sysname, X? 7s
@MaxMinutes INT, Yij_'0vZ
@NewSize INT 3w&Z:<
USE tablename -- 要操作的数据库名 6GMwB@ b
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 s:xt4<
@MaxMinutes = 10, -- Limit on time allowed to wrap log. nTv^][
@NewSize = 1 -- 你想设定的日志文件的大小(M) &8HJ4Vj2
-- Setup / initialize +8}8b_bgH
DECLARE @OriginalSize int *RD<*l
SELECT @OriginalSize = size ~--b#o{
FROM sysfiles 6
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WHERE name = @LogicalFileName *#.Ku(C+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \2 Yo*jE}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + a|-B# S
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' V~7Oa2'#B
FROM sysfiles wBCBZs$H
WHERE name = @LogicalFileName ^tL]QE?|
CREATE TABLE DummyTrans Mj W{JR)I
(DummyColumn char (8000) not null) 0`4Fa^o]h
DECLARE @Counter INT, k r5'E#
@StartTime DATETIME, Wgm{
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@TruncLog VARCHAR(255) wvI}|c
SELECT @StartTime = GETDATE(), (V>/[Ev
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' x-T7
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) 04c`7[
EXEC (@TruncLog) TBmmC}PEd
-- Wrap the log if necessary. F%I*m^7d
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired uQl=?085
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Rhzcm`"
AND (@OriginalSize * 8 /1024) > @NewSize PTpGZ2FZ
BEGIN -- Outer loop. PNpH)'C|
SELECT @Counter = 0 &UQP9wS4v
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) g$U7bCHG
BEGIN -- update ua!RwSo
INSERT DummyTrans VALUES ('Fill Log') eB_ M *+^
DELETE DummyTrans `svOPB4C'
SELECT @Counter = @Counter + 1 V^kl_!@
END m!WDXt
EXEC (@TruncLog) 8bX?HeYrr
END PEMuIYm$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + T,uJO<
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + V!f'
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' COL_c<\
FROM sysfiles rT'<6]`
WHERE name = @LogicalFileName B/K{sI
DROP TABLE DummyTrans F~l:WQAj
SET NOCOUNT OFF 5XZ\7Z|
8、说明:更改某个表 m^;A]0h+
exec sp_changeobjectowner 'tablename','dbo' D26A%[^O
9、存储更改全部表 LIh71Vg/cc
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Q[.d
@OldOwner as NVARCHAR(128), )2?A|f8
@NewOwner as NVARCHAR(128) vPsf{[Kr
AS -:Jn|=
DECLARE @Name as NVARCHAR(128) ]m\:XhI*<
DECLARE @Owner as NVARCHAR(128) S~ZRqL7ZO
DECLARE @OwnerName as NVARCHAR(128) w1)SuMFK_
DECLARE curObject CURSOR FOR i%otvDn1
select 'Name' = name, 2f2.;D5g_'
'Owner' = user_name(uid) |#5_VEG
from sysobjects
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where user_name(uid)=@OldOwner -v~XS-F
order by name O7xBMqMf
OPEN curObject xL|4'8
FETCH NEXT FROM curObject INTO @Name, @Owner "uU[I,h
WHILE(@@FETCH_STATUS=0) q;<Q-jr&O
BEGIN ~2}^
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if @Owner=@OldOwner 2(>=@q.1H
begin eB5<N?;s
set @OwnerName = @OldOwner + '.' + rtrim(@Name) tVHQ$jJY%
exec sp_changeobjectowner @OwnerName, @NewOwner zfA"xD
end IWnyqt(k
-- select @name,@NewOwner,@OldOwner k(wJ6pc
FETCH NEXT FROM curObject INTO @Name, @Owner Dl_SEf6b
END |dqvv
close curObject 1A{iUddR
deallocate curObject u`wT_?%w
GO
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10、SQL SERVER中直接循环写入数据 [zhcb+^5l
declare @i int E akS(Q?
set @i=1 ;Rd\yAG
while @i<30 6gD|QC~;
begin l`vr({A
insert into test (userid) values(@i) k6??+b:rE
set @i=@i+1 y:dwx *Q9I
end 0zqTX< A
小记存储过程中经常用到的本周,本月,本年函数 Cz#3W8jV
Dateadd(wk,datediff(wk,0,getdate()),-1) M5l*D'GE]
Dateadd(wk,datediff(wk,0,getdate()),6) &;@U54,wV
Dateadd(mm,datediff(mm,0,getdate()),0) \\,z[C
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) n4G53+y'
Dateadd(yy,datediff(yy,0,getdate()),0) .iH#8Z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) @-BgPDi.Z
上面的SQL代码只是一个时间段 f2FGod<CzN
Dateadd(wk,datediff(wk,0,getdate()),-1) ,E8~^\HV
Dateadd(wk,datediff(wk,0,getdate()),6) -1 _7z{.
就是表示本周时间段. 9p9-tJfH.
下面的SQL的条件部分,就是查询时间段在本周范围内的: R,ddH[3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6)
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而在存储过程中 "6P- 0CJ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) x^JjoI2vf
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) }NETiJ"6