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。 #w L(<nE
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一、基础 .g/!u(iy
1、说明:创建数据库 NATi)A"TZ
CREATE DATABASE database-name ^(&2
2、说明:删除数据库 ANPG3^w
drop database dbname 5tv*uz|fv
3、说明:备份sql server 05ZYOs }
--- 创建 备份数据的 device X:Y1g)|K
USE master O#igH
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~^.,Ftkb@7
--- 开始 备份 fp||<B
BACKUP DATABASE pubs TO testBack PE7V1U#$o,
4、说明:创建新表 ^Whc<>|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) cV:Q(|QC
根据已有的表创建新表: mV]~}7*Y;
A:create table tab_new like tab_old (使用旧表创建新表) _x5-!gK
B:create table tab_new as select col1,col2... from tab_old definition only 2h5T$[fV
5、说明:删除新表 }c/#WA|b
drop table tabname -T+yS BO_3
6、说明:增加一个列 R&s/s`pLW
Alter table tabname add column col type =SJ[)|
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。 ~(m6dPm$}m
7、说明:添加主键: Alter table tabname add primary key(col) F4(;O7j9
说明:删除主键: Alter table tabname drop primary key(col) _BG`!3U+
8、说明:创建索引:create [unique] index idxname on tabname(col....) *QW.#y>"j
删除索引:drop index idxname 9^SrOW6~
注:索引是不可更改的,想更改必须删除重新建。 N
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9、说明:创建视图:create view viewname as select statement 7TAoWD3
删除视图:drop view viewname j5Yli6r?3-
10、说明:几个简单的基本的sql语句 1slt[&4N
选择:select * from table1 where 范围 \^F6)COy
插入:insert into table1(field1,field2) values(value1,value2) ZbH6$2r
删除:delete from table1 where 范围 6:r1^q6A9L
更新:update table1 set field1=value1 where 范围 ;Xidv9c
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! T5~Qfl?Y
排序:select * from table1 order by field1,field2 [desc] |q o3
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总数:select count as totalcount from table1 $o\Uq
求和:select sum(field1) as sumvalue from table1 +$~HRbo
平均:select avg(field1) as avgvalue from table1 YVHDk7s
最大:select max(field1) as maxvalue from table1 !/&~Feb
最小:select min(field1) as minvalue from table1 b(ryk./ogx
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11、说明:几个高级查询运算词 /|e"0;{
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A: UNION 运算符 yC=vTzzp
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。 a-TsD}'X
B: EXCEPT 运算符 !as<UH"\
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。 EVmE{XlD;
C: INTERSECT 运算符 D+_PyK~jc
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。 EZiGi[t7
注:使用运算词的几个查询结果行必须是一致的。 b OmM~pD
12、说明:使用外连接 c9E9Rx
A、left outer join: DPtyCgH
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。 *DoEDw
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 El&pux2
B:right outer join: WU,72g=
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。 =Jl1D*B*
C:full outer join: f<'&_*7,|t
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。 { K0T%.G
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二、提升 Ez1*}
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ;1OTK6
法一:select * into b from a where 1<>1 ?y45#Tk]
法二:select top 0 * into b from a E[Io8|QA
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) " Gn; Q-@
insert into b(a, b, c) select d,e,f from b; TuCOoz@d
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) a
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 LP)mp cQ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. K6oXnz}
4、说明:子查询(表名1:a 表名2:b) {:FITF3o
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) n_ez6{
5、说明:显示文章、提交人和最后回复时间 >a-+7{};
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b et ~gO!1:*
6、说明:外连接查询(表名1:a 表名2:b) }EIwkz8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =L
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7、说明:在线视图查询(表名1:a ) n0i&P9@B1
select * from (SELECT a,b,c FROM a) T where t.a > 1; o%9>elOju
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 ?RzT0HRd
select * from table1 where time between time1 and time2 &s;%(c04A
select a,b,c, from table1 where a not between 数值1 and 数值2 E;d 5$
9、说明:in 的使用方法 \+~4t
select * from table1 where a [not] in ('值1','值2','值4','值6') y?@Y\ b
10、说明:两张关联表,删除主表中已经在副表中没有的信息 x[^A9
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) A7RX2
11、说明:四表联查问题: p+7BsW.l
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 ..... :d2u? +F
12、说明:日程安排提前五分钟提醒 jRkq^}
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 1=a}{)0h
13、说明:一条sql 语句搞定数据库分页 *(MvNN*
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 jrl6):x
14、说明:前10条记录 CzEn_ZMb
select top 10 * form table1 where 范围 XZ&v3ul
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.)
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) bg*{1^
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 .nH
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(select a from tableA ) except (select a from tableB) except (select a from tableC) 66 Xt=US
17、说明:随机取出10条数据 `s_TY%&_}g
select top 10 * from tablename order by newid() S+y2eP G
18、说明:随机选择记录 Lb{D5k*XU
select newid() Qd4T?5 vG
19、说明:删除重复记录 (*x"6)`
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) W7o/
20、说明:列出数据库里所有的表名 ,7g;r_qwA
select name from sysobjects where type='U' u"gp">
21、说明:列出表里的所有的 Madaxx
select name from syscolumns where id=object_id('TableName') T!a[@,)_
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。 U}0/V
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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 E}=,"i
显示结果: dZgfls
type vender pcs {@$3bQ
电脑 A 1 UVJ(iNK"
电脑 A 1 9p4U\hx
光盘 B 2 m^.C(}
光盘 A 2 >[@d&28b%
手机 B 3 @ 1A_eF
手机 C 3 ?63JQ.;
23、说明:初始化表table1 vNSf:5H$
TRUNCATE TABLE table1 3pW
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24、说明:选择从10到15的记录 sK?-@
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc F8Wq&X#r
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三、技巧 }z+"3A|
1、1=1,1=2的使用,在SQL语句组合时用的较多 'e64%t
"where 1=1" 是表示选择全部 "where 1=2"全部不选, r_E)HL/A
如: DZ.trtK
if @strWhere !='' 34Khg
begin 7~nCK
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 5qSZ>DZ
end -$t,}3
else qK
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begin PFy;qk
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' S/<"RfVU#o
end OrEuQ-,i@
我们可以直接写成 bTQa'y`3
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere cgxFEv
2、收缩数据库 =/JF-#n/MA
--重建索引 #3yw
DBCC REINDEX a<wQzgxG
DBCC INDEXDEFRAG /dJ)TW(Ir
--收缩数据和日志 _c
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DBCC SHRINKDB fb.\V]K
DBCC SHRINKFILE Iei7!KLW
3、压缩数据库 ~J>gVg%66
dbcc shrinkdatabase(dbname) {H=oxa
4、转移数据库给新用户以已存在用户权限 i1qS ns
exec sp_change_users_login 'update_one','newname','oldname' _m9~*
go G;(onJz
5、检查备份集 JsmbW|t^
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 6R;)
6、修复数据库 VLcyPM@"Q!
ALTER DATABASE [dvbbs] SET SINGLE_USER N@Xg5huO
GO Qm.z@DwFM{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9?uqQ
GO e7@li<3>d
ALTER DATABASE [dvbbs] SET MULTI_USER C(-[ Y!
GO j\2]M
7、日志清除 }FPM-M3y
SET NOCOUNT ON O6y @G
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DECLARE @LogicalFileName sysname, [O^}rUqq
@MaxMinutes INT, 2Sge
@NewSize INT IWAj Mwo
USE tablename -- 要操作的数据库名 ;"1/#CY773
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 h ZoC _\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 3YR *
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@NewSize = 1 -- 你想设定的日志文件的大小(M) sf Dg/ a
-- Setup / initialize {bN Y
DECLARE @OriginalSize int Ns'FH(:
SELECT @OriginalSize = size y0,Ft/D
FROM sysfiles xM&EL>m>L
WHERE name = @LogicalFileName G9\EZ\x!
SELECT 'Original Size of ' + db_name() + ' LOG is ' + A&N$tH
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :I2H&,JT
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1|W2s\
FROM sysfiles GF&_~48GD
WHERE name = @LogicalFileName Iq+2mQi*/k
CREATE TABLE DummyTrans I$n+DwKcN
(DummyColumn char (8000) not null) $( S*GF$S
DECLARE @Counter INT, a;%I\w;2
@StartTime DATETIME, > gr<^$
@TruncLog VARCHAR(255) R0{Qy*YQ`
SELECT @StartTime = GETDATE(), 5i6VZv
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ri: ,q/-
DBCC SHRINKFILE (@LogicalFileName, @NewSize)
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EXEC (@TruncLog) oWI!u 5
-- Wrap the log if necessary. "c6<zP
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired *\D}eBd|
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) jDkm:X}:
AND (@OriginalSize * 8 /1024) > @NewSize GSP?X$E
BEGIN -- Outer loop. 012Lwd
SELECT @Counter = 0 yX`#s]M
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ((qGh>*
BEGIN -- update 975
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INSERT DummyTrans VALUES ('Fill Log') avg4K*v v
DELETE DummyTrans {#N%Bq}
SELECT @Counter = @Counter + 1 \6{LR&
END P/G>/MD/l
EXEC (@TruncLog) )AI?x@
END 7#ofNH J
SELECT 'Final Size of ' + db_name() + ' LOG is ' + i0\)%H:z
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + SyAo,
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' pl|h>4af
FROM sysfiles yplG18
WHERE name = @LogicalFileName `^x9(i/NE
DROP TABLE DummyTrans grspt}
SET NOCOUNT OFF gGEIK0\{
8、说明:更改某个表 z3W3=@
exec sp_changeobjectowner 'tablename','dbo' J:AMnUOcDi
9、存储更改全部表 J1X~vQAe
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch NO2(vE
@OldOwner as NVARCHAR(128), zW5C1:.3K
@NewOwner as NVARCHAR(128) pM9yOY
AS }RIU8=P
DECLARE @Name as NVARCHAR(128) E=]]b;u-n
DECLARE @Owner as NVARCHAR(128) ,:UX<6l
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DECLARE @OwnerName as NVARCHAR(128) -9d%+O~v6~
DECLARE curObject CURSOR FOR Z/g]o#
select 'Name' = name, VO_dA4C}z
'Owner' = user_name(uid) R5(F)abi
from sysobjects H:Y&OZ
where user_name(uid)=@OldOwner W:vr@e6
order by name JhP\u3 QE
OPEN curObject ezUQ>
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FETCH NEXT FROM curObject INTO @Name, @Owner DZk1ZLz
WHILE(@@FETCH_STATUS=0) aClA{
BEGIN nxfoWy
if @Owner=@OldOwner ugLlI2 nJ
begin gi$XB}L+X
set @OwnerName = @OldOwner + '.' + rtrim(@Name) psUE!~9,
exec sp_changeobjectowner @OwnerName, @NewOwner C6]OAUXy:F
end -{{[cTI
-- select @name,@NewOwner,@OldOwner nQ-mmY>#
FETCH NEXT FROM curObject INTO @Name, @Owner ykmv'a$-4
END p0VUh!
close curObject Z9[+'ZWt
deallocate curObject vy9dAl
GO d:rGyA]
10、SQL SERVER中直接循环写入数据 9:8|)a(1
declare @i int cG_Vc[
set @i=1 IZrk1fh
while @i<30 a
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begin wk @,wOt
insert into test (userid) values(@i) 5jZiJw(
set @i=@i+1 jatr/
end !%[S49s
小记存储过程中经常用到的本周,本月,本年函数 suVmg-d
Dateadd(wk,datediff(wk,0,getdate()),-1) 6Hf,6>
Dateadd(wk,datediff(wk,0,getdate()),6) BJy;-(JP
Dateadd(mm,datediff(mm,0,getdate()),0) Vte EDL/w
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) >cgpaj x*
Dateadd(yy,datediff(yy,0,getdate()),0) ^ R~~L
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) U(,.D}PG
上面的SQL代码只是一个时间段 7lA:)a_!]
Dateadd(wk,datediff(wk,0,getdate()),-1) -6C +LbV
Dateadd(wk,datediff(wk,0,getdate()),6) {HrZ4xQnpV
就是表示本周时间段. J^
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下面的SQL的条件部分,就是查询时间段在本周范围内的: `^6 ,kI-c
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) #/70!+J_UF
而在存储过程中 h-QLV[^
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Gquuy7[&
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) kbI/4IRW