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。 (fNUj4[
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一、基础 mpAR7AG6
1、说明:创建数据库 W>r#RXmh
CREATE DATABASE database-name >EL)X
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2、说明:删除数据库 hT$~ygQ
drop database dbname qPB8O1fyU
3、说明:备份sql server tO7v4
--- 创建 备份数据的 device LTNj| u
USE master 3!Sp0P
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' :q8b;*:
--- 开始 备份 3czeTj
BACKUP DATABASE pubs TO testBack [U}+sTQ
4、说明:创建新表 [Vd[-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) *D o/+[Ae
根据已有的表创建新表: ur
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A:create table tab_new like tab_old (使用旧表创建新表) ?88[|;b3
B:create table tab_new as select col1,col2... from tab_old definition only .)}@J5P)
5、说明:删除新表 /V3=KY`_J
drop table tabname F:*W5xX
6、说明:增加一个列 sK{l 9
Alter table tabname add column col type .Ha'p.
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 L;gO;vO
7、说明:添加主键: Alter table tabname add primary key(col) Cm$.<CV
说明:删除主键: Alter table tabname drop primary key(col) gu #-O?B
8、说明:创建索引:create [unique] index idxname on tabname(col....) O^/Maa/D1
删除索引:drop index idxname mNmLyU=d
注:索引是不可更改的,想更改必须删除重新建。 a+hd(JX0~
9、说明:创建视图:create view viewname as select statement u@ jX+\
删除视图:drop view viewname <%xS{!'}
10、说明:几个简单的基本的sql语句 ;a-$D]Db
选择:select * from table1 where 范围 *f,DhT/P
插入:insert into table1(field1,field2) values(value1,value2) R'kyrEO
删除:delete from table1 where 范围 : ^ 8
更新:update table1 set field1=value1 where 范围 'n<iU st
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! &1+X\c+tb
排序:select * from table1 order by field1,field2 [desc] ;'81jbh
总数:select count as totalcount from table1 3 ?Y|
求和:select sum(field1) as sumvalue from table1 _qbIh
平均:select avg(field1) as avgvalue from table1 ?Ma~^0
最大:select max(field1) as maxvalue from table1 aM7uBx\8 5
最小:select min(field1) as minvalue from table1 ix#epuN
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11、说明:几个高级查询运算词 Cy*|&=>j
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A: UNION 运算符 @ym/27cRE
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。 `DT3x{}_S
B: EXCEPT 运算符 + >cBVx6
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。 %,hV[[ @.
C: INTERSECT 运算符
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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。 54rkC/B>
注:使用运算词的几个查询结果行必须是一致的。 e"
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12、说明:使用外连接 Y?ez9o:/#
A、left outer join: ICAH G7 ,
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。 q~o,WZG
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 6sa"O89
B:right outer join: ~G27;Npy
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。 8foJ I^3
C:full outer join: YC_1Ks
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。 Ela-,(Glk
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二、提升 }E`dZW*!!
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) G;f/Tch
法一:select * into b from a where 1<>1 0oEOre3^%
法二:select top 0 * into b from a ~tOAT;g}q
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) tK
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insert into b(a, b, c) select d,e,f from b; -{`@=U
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) K-&V,MI
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 JWA@+u*k
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. `# sTmC)
4、说明:子查询(表名1:a 表名2:b) lY*[tmz)
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) o[E_Ge}g8
5、说明:显示文章、提交人和最后回复时间 0euuT@_$
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )"+(butI&
6、说明:外连接查询(表名1:a 表名2:b) !?^b[
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 3=W!4
7、说明:在线视图查询(表名1:a ) !Ci~!)$z6
select * from (SELECT a,b,c FROM a) T where t.a > 1; y^7}oH _
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 CR2_;x:0
select * from table1 where time between time1 and time2 g@\fZTO
select a,b,c, from table1 where a not between 数值1 and 数值2 $ "Bh]-
9、说明:in 的使用方法 :8A!HI}m{
select * from table1 where a [not] in ('值1','值2','值4','值6') =}PdH`S
10、说明:两张关联表,删除主表中已经在副表中没有的信息 BcD&sQ2F
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) c$wsH25KH8
11、说明:四表联查问题: -R{V-
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 ..... y1=NF
12、说明:日程安排提前五分钟提醒 b,KcBQ.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 qH['09/F6
13、说明:一条sql 语句搞定数据库分页 oA1a /[#
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 #M A4
14、说明:前10条记录 vky .^
select top 10 * form table1 where 范围 fr!Pj(Q1
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.) ':R,53tjl
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) %p
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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 gNG r!3*)w
(select a from tableA ) except (select a from tableB) except (select a from tableC) )/t?!T.[
17、说明:随机取出10条数据 5s?Hxn
select top 10 * from tablename order by newid() T)\"Xj
18、说明:随机选择记录 k? Xc
select newid() 3OM2Y_
19、说明:删除重复记录 W-/}q0h
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) (@WA1oNG
20、说明:列出数据库里所有的表名 % >;#9"O4
select name from sysobjects where type='U' Zf5`XslA.
21、说明:列出表里的所有的 zXsc1erli
select name from syscolumns where id=object_id('TableName') _4 cvX
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。 pStk/te,XK
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 {)AMw q
显示结果: 4`Ic&c/
type vender pcs W[+|}
电脑 A 1 -Z-IF#%
电脑 A 1 )J?{+3
光盘 B 2 -R>}u'EG>
光盘 A 2 (RtueEb.~E
手机 B 3 ,YhdY6
手机 C 3 %6--}bY^
23、说明:初始化表table1 9Ct`
TRUNCATE TABLE table1 -)vEWn$3<
24、说明:选择从10到15的记录 7RDDdF E!
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc nADX0KI
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三、技巧 |y<),j6
1、1=1,1=2的使用,在SQL语句组合时用的较多 a?YCn!
"where 1=1" 是表示选择全部 "where 1=2"全部不选, D#S\!>m
如: >yJ9U,Y
if @strWhere !='' *Ei|fe$sa
begin _7DkS}NJs
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 1009ES7*
end 3sCFHn#c
else i
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begin fIF<g@s
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' VOsqJJ3
end zY+Fl~$S
我们可以直接写成 Jx#k,Z4
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7m#[!%D
2、收缩数据库 6mH/ m&
--重建索引 80M;4nH^5
DBCC REINDEX Nx#4W1B[`H
DBCC INDEXDEFRAG S]sk7
--收缩数据和日志 yk2 !8
DBCC SHRINKDB :Sg_tOf
DBCC SHRINKFILE p
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3、压缩数据库 p1c3Q$>i
dbcc shrinkdatabase(dbname) >MJ?g-
4、转移数据库给新用户以已存在用户权限 KNgH|5Pb
exec sp_change_users_login 'update_one','newname','oldname' EliTFxp
go i~J;G#b
5、检查备份集 ~8|t*@D
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ~tB;@e
6、修复数据库 avp;*G}
ALTER DATABASE [dvbbs] SET SINGLE_USER +*oS((0s
GO HmK*b Z
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK a'\By?V]
GO m\/(w_/?
ALTER DATABASE [dvbbs] SET MULTI_USER R6 XuA(5
GO =rPrPb
7、日志清除 Kt>X[o3m,
SET NOCOUNT ON @&1Wyp
DECLARE @LogicalFileName sysname, 9@$,oM=
@MaxMinutes INT, N^VD=<#T
@NewSize INT /RLq>#:h**
USE tablename -- 要操作的数据库名 `nR %Cav,U
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 t<:D@J]a
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #0b&^QL
@NewSize = 1 -- 你想设定的日志文件的大小(M) b4Y8N"hL%
-- Setup / initialize RnfXN)+P
DECLARE @OriginalSize int +kdySWF
SELECT @OriginalSize = size mxSKG>
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FROM sysfiles !0/z>#b
WHERE name = @LogicalFileName !~<siy
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,(G%e
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' f]~c)P
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FROM sysfiles }wSi~^*
WHERE name = @LogicalFileName h!&sNzX
CREATE TABLE DummyTrans PU9`<3z5
(DummyColumn char (8000) not null) <I;*[;AK
DECLARE @Counter INT, U3vEdw<lV
@StartTime DATETIME, YEjY8]t
@TruncLog VARCHAR(255) M
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SELECT @StartTime = GETDATE(), >zY \Llv
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' F)$K
DBCC SHRINKFILE (@LogicalFileName, @NewSize) o?Sla_D
EXEC (@TruncLog) ;@ WV-bLe
-- Wrap the log if necessary. WKA'=,`v
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired H'RL62!
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 6*GjP ;S=
AND (@OriginalSize * 8 /1024) > @NewSize Mu_i$j$vvP
BEGIN -- Outer loop. `29TY&p+"
SELECT @Counter = 0 '!vc/Hw
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) LU!1s@
BEGIN -- update -'rj&x{Q)U
INSERT DummyTrans VALUES ('Fill Log') iZ[tHw||
DELETE DummyTrans Q"a2.9Eo
SELECT @Counter = @Counter + 1 Z#`0txCF
END SP
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EXEC (@TruncLog) guN4-gGDr<
END c)C 5KaiPG
SELECT 'Final Size of ' + db_name() + ' LOG is ' + IN^9uL]B
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ST1Ts5I
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' *2u
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FROM sysfiles 8dT'xuch
WHERE name = @LogicalFileName rlok%Rt4Z
DROP TABLE DummyTrans }\v^+scD
SET NOCOUNT OFF 5IMSNGS
8、说明:更改某个表 !jS4!2'
exec sp_changeobjectowner 'tablename','dbo' hN`gB#N3
9、存储更改全部表 v@ONo?)
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch +I|8Q|^SD
@OldOwner as NVARCHAR(128), X7aXxPCq1
@NewOwner as NVARCHAR(128) 6(56,i<#/
AS & %}/AoU
DECLARE @Name as NVARCHAR(128) TW`mxj_J2
DECLARE @Owner as NVARCHAR(128) g jG2
DECLARE @OwnerName as NVARCHAR(128) #G_/.h@
DECLARE curObject CURSOR FOR x;$|#]+
select 'Name' = name, ]S8LY.Az5
'Owner' = user_name(uid) }$&WC:Lg
from sysobjects sz09+4h#
where user_name(uid)=@OldOwner bLG ]Wa
order by name Wb=Jj 9;
OPEN curObject z<C[nR$N
FETCH NEXT FROM curObject INTO @Name, @Owner ]H 2R
WHILE(@@FETCH_STATUS=0) OKY+M^PP
BEGIN 5S/>l_od$2
if @Owner=@OldOwner >M^&F6
begin vrcE]5(:s
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fDuwgY0
exec sp_changeobjectowner @OwnerName, @NewOwner |uha 38~
end *Jnh";~b
-- select @name,@NewOwner,@OldOwner |paP<$
FETCH NEXT FROM curObject INTO @Name, @Owner q&M:17+:Q
END K_-MkY?+
close curObject =mrY/:V
deallocate curObject LZWS^77
GO C@@$"}%v2
10、SQL SERVER中直接循环写入数据 AF#_nK)@
declare @i int O.:I,D&]
set @i=1 `!c,y~r[
while @i<30 .K9l*-e[=
begin cqQRU
insert into test (userid) values(@i) .Vx|'-u
set @i=@i+1 GEE
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end dXP6"V@iI
小记存储过程中经常用到的本周,本月,本年函数 9={N4}<
Dateadd(wk,datediff(wk,0,getdate()),-1) k8&FDz
Dateadd(wk,datediff(wk,0,getdate()),6) Fe="EDh
Dateadd(mm,datediff(mm,0,getdate()),0) ?R?Grw)`H
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) r=csi
Dateadd(yy,datediff(yy,0,getdate()),0) Z H-5Qy_
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |QYZRz
上面的SQL代码只是一个时间段 jKt-~:
Dateadd(wk,datediff(wk,0,getdate()),-1) J/S{FxNe]
Dateadd(wk,datediff(wk,0,getdate()),6) ^@_).:oX7
就是表示本周时间段. _^;;i4VZ
下面的SQL的条件部分,就是查询时间段在本周范围内的: Ex,JB +
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) O_CT+Ou
而在存储过程中 x}"Q8kD
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ##~!M(c
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) LP>UU ,Z