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。 3?V'O6
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一、基础 =nCA=-Jv
1、说明:创建数据库 ]dGH
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CREATE DATABASE database-name udUc&pX
2、说明:删除数据库 9*I[q[>9
drop database dbname 7I w^
3、说明:备份sql server B(Yg1jAe
--- 创建 备份数据的 device q-Z<.GTq
USE master Wo&22,EB
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ":+d7xR?o
--- 开始 备份 agwbjkU/
BACKUP DATABASE pubs TO testBack " J9
4、说明:创建新表 IQ\!wWKmY
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) gD)M7`4
根据已有的表创建新表: bgE]Wk0
A:create table tab_new like tab_old (使用旧表创建新表) IIY_Q9in
B:create table tab_new as select col1,col2... from tab_old definition only m33&obSP
5、说明:删除新表 Qc*p+N+$
drop table tabname ?0X$ox
6、说明:增加一个列 Ux',ma1JK
Alter table tabname add column col type JzN "o'
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。
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7、说明:添加主键: Alter table tabname add primary key(col) kXhd]7ru
说明:删除主键: Alter table tabname drop primary key(col) ;q-c[TZC
8、说明:创建索引:create [unique] index idxname on tabname(col....) Cu%BU}(
删除索引:drop index idxname >b\|%=(x!*
注:索引是不可更改的,想更改必须删除重新建。 ~\-=q^/!
9、说明:创建视图:create view viewname as select statement -<x%
删除视图:drop view viewname ^n~Kr1}nj
10、说明:几个简单的基本的sql语句 31^/9lb
选择:select * from table1 where 范围 xS@jV6E~
插入:insert into table1(field1,field2) values(value1,value2) <fBJ@>
删除:delete from table1 where 范围 e^q^AP+*
更新:update table1 set field1=value1 where 范围 1d49&-N
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! hb8oq3*x
排序:select * from table1 order by field1,field2 [desc] aO1.9!<v
总数:select count as totalcount from table1 ?pJ2"/K
求和:select sum(field1) as sumvalue from table1 2d|^$$#`
平均:select avg(field1) as avgvalue from table1 W!ug^2"
最大:select max(field1) as maxvalue from table1 `_LQs9J0J
最小:select min(field1) as minvalue from table1 WVQHb3Pe0
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11、说明:几个高级查询运算词 ZJbaioc\
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A: UNION 运算符 ;FwUUKj
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。 $ H@
B: EXCEPT 运算符 )2E vZn
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。 ozS'n]8*
C: INTERSECT 运算符 6E_~8oEl
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。 .DwiIr'
注:使用运算词的几个查询结果行必须是一致的。 [%LGiCU]
12、说明:使用外连接 )$Ib6tYY
A、left outer join: !4^Lv{1QZ
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。 h] )&mFiE"
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 u7J:ipyiq2
B:right outer join: of7'?]w
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。 9BOn8p;yz
C:full outer join: 5![ ILa_
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。 5R.jhYAj
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二、提升 _G4U
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !N\_D
法一:select * into b from a where 1<>1 \g]rOYW
法二:select top 0 * into b from a }<2|6 {
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) oVUsI,8
insert into b(a, b, c) select d,e,f from b; b[&ri:AC
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) &> .QDO
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 b-`P-
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. H,;ZFg /v8
4、说明:子查询(表名1:a 表名2:b) #Sy~t{4
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) h+q#|N
5、说明:显示文章、提交人和最后回复时间 U;ujN 8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b nF3Sfw,
6、说明:外连接查询(表名1:a 表名2:b) &% (1?\~u
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c g~|x^d^;|
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; .d#Hh&jj
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 pR*3Q@Ng
select * from table1 where time between time1 and time2 #"C*dNAB
select a,b,c, from table1 where a not between 数值1 and 数值2 6>)KiigZ\
9、说明:in 的使用方法 +N~{6*@uz,
select * from table1 where a [not] in ('值1','值2','值4','值6') .aK=z)
10、说明:两张关联表,删除主表中已经在副表中没有的信息 G'HLnx}Yi
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) `"~ X1;
11、说明:四表联查问题: /f.
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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 ..... Sxy3cv53
12、说明:日程安排提前五分钟提醒 3!?QQT,!)
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 LBpAR|
13、说明:一条sql 语句搞定数据库分页 g*9&3ov
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 E}36
14、说明:前10条记录 ?q'r9Ehe
select top 10 * form table1 where 范围 ``Um$i~e%
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>nT
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) b?9'-hK<
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 La^Zr,T!
(select a from tableA ) except (select a from tableB) except (select a from tableC) k]TJL9Q
17、说明:随机取出10条数据 Jju?v2y`
select top 10 * from tablename order by newid() k[1[Y{n.
18、说明:随机选择记录 ?K.!^G
select newid() aO<H!hK
19、说明:删除重复记录 #TP Y%
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) )pey7-P7g5
20、说明:列出数据库里所有的表名 {5fq4AA6
select name from sysobjects where type='U' ;ov}%t>UD
21、说明:列出表里的所有的 a}Jy o!.
select name from syscolumns where id=object_id('TableName') Xn<|6u
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。 ;ZrFy=Iv
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 +hT9V1'-D
显示结果: yg4ILL
type vender pcs .e:+Ek+
电脑 A 1 6& 9q6IIy
电脑 A 1 Qbj:^{`>(
光盘 B 2 }4>#s$.2
光盘 A 2 OL&VisJ{75
手机 B 3 S7hfwu&7F
手机 C 3 RQn3y-N]
23、说明:初始化表table1 N4_V
TRUNCATE TABLE table1 Rk{2ZUeg
24、说明:选择从10到15的记录 C2%Yr y
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 0*u X2*
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三、技巧 0I.!
1、1=1,1=2的使用,在SQL语句组合时用的较多 t`4o&vsj=
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ,!^w
如:
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if @strWhere !='' bNz2Uo!0K
begin SYK?5_804
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere E!>l@
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end '8Lc}-M4
else z: W1(/W~
begin %u$dN9cw
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Z@:R'u2Lk
end Tb]' b
我们可以直接写成 wsCT9&p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %PU{h
2、收缩数据库 *FoPs
--重建索引 =}4lx^`oeT
DBCC REINDEX M7IQJFra
DBCC INDEXDEFRAG `?Xt ,
--收缩数据和日志 :!g zx n
DBCC SHRINKDB cE]#23
DBCC SHRINKFILE ~;Xkt G:
3、压缩数据库 ;%aWA
dbcc shrinkdatabase(dbname) Fqp~1>wi
4、转移数据库给新用户以已存在用户权限 GUK3`}!%
exec sp_change_users_login 'update_one','newname','oldname' !HHbd|B_
go &28n1
5、检查备份集 @-qC".CI
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' m4@w M?
6、修复数据库 !J@pox-t
ALTER DATABASE [dvbbs] SET SINGLE_USER FwGMrJW
GO uv
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?rH=< #@
GO ]^\+B4
ALTER DATABASE [dvbbs] SET MULTI_USER =!Y{Mz
GO h?:Y\DlU'
7、日志清除 _.Bite^
SET NOCOUNT ON OECXNx
DECLARE @LogicalFileName sysname, %4E7 Tu,1
@MaxMinutes INT, IN9o$CZ:
@NewSize INT 8M'6Kcr
USE tablename -- 要操作的数据库名 #[#dc]D
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 "ae55ft//
@MaxMinutes = 10, -- Limit on time allowed to wrap log. S\UM0G}v
@NewSize = 1 -- 你想设定的日志文件的大小(M) !P26$US%P
-- Setup / initialize RsDI7v
DECLARE @OriginalSize int $yb8..+
SELECT @OriginalSize = size s2ys>2k
FROM sysfiles YB} _zuZ4&
WHERE name = @LogicalFileName N6<23kYM
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8Lpy`He
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' j{'@g[HW
FROM sysfiles Lsozl<@
WHERE name = @LogicalFileName ARu^hz=
CREATE TABLE DummyTrans AH],>i3
(DummyColumn char (8000) not null) uL4@e
DECLARE @Counter INT, c$'UfW
@StartTime DATETIME, p8^^Pva/
@TruncLog VARCHAR(255) 6%_d m'
SELECT @StartTime = GETDATE(), ':w6{b
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' f i!wrvO
DBCC SHRINKFILE (@LogicalFileName, @NewSize) HF\L`dJX?
EXEC (@TruncLog) i,,>@R
-- Wrap the log if necessary. \9/n~/{
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired LVLh&9
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) s}9aZ
AND (@OriginalSize * 8 /1024) > @NewSize GW{Nc!)
BEGIN -- Outer loop. ]yVB66l
SELECT @Counter = 0 I|O~F e.
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Qg
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BEGIN -- update D\V}Eo';6
INSERT DummyTrans VALUES ('Fill Log') T+4Musu{V
DELETE DummyTrans &:jE+l
SELECT @Counter = @Counter + 1 qW<: `y
END 8a)EL*LH`
EXEC (@TruncLog) d*>M<6b-
END >k\*NW
SELECT 'Final Size of ' + db_name() + ' LOG is ' + uR)@v^$FE
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + x{ZVq 4
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [bT@Y:X@`
FROM sysfiles xSOL4
WHERE name = @LogicalFileName u%[*;@;9+
DROP TABLE DummyTrans U0N[~yW(t1
SET NOCOUNT OFF rjR
8、说明:更改某个表 LbYI{|_Js
exec sp_changeobjectowner 'tablename','dbo' WD?V1:>+
9、存储更改全部表 vP~F+z
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch P7y[9|^
@OldOwner as NVARCHAR(128), 329xo03-[
@NewOwner as NVARCHAR(128) In;z\"NN4
AS v}Aw!Dv/
DECLARE @Name as NVARCHAR(128) 'b^:"\t'Rh
DECLARE @Owner as NVARCHAR(128) Vd1K{rH#
DECLARE @OwnerName as NVARCHAR(128) D@JHi'F
DECLARE curObject CURSOR FOR "+Qh,fTt
select 'Name' = name, <0LB]zDWe6
'Owner' = user_name(uid) 2.lnT{
from sysobjects eO9nn9lql
where user_name(uid)=@OldOwner 4*9Dh
order by name <?J7Z|
OPEN curObject z~Pmh%b
FETCH NEXT FROM curObject INTO @Name, @Owner 8\V-aow
WHILE(@@FETCH_STATUS=0) <NAR'{f
BEGIN (7wR*vO^
if @Owner=@OldOwner n[WeN NU
begin &S-& 'ZAY
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2b"5/$|6
exec sp_changeobjectowner @OwnerName, @NewOwner ?rK%;GTo
end 88*RlxU
-- select @name,@NewOwner,@OldOwner ^#Y6
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FETCH NEXT FROM curObject INTO @Name, @Owner }mGD`5[`
END =Fs LF
close curObject i-=ff
deallocate curObject Zn} )&Xt
GO 7cy~qg
10、SQL SERVER中直接循环写入数据 B*AMo5
declare @i int SWGa%6|
set @i=1 %i
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while @i<30 jlP7'xt1%
begin !?>)[@2
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insert into test (userid) values(@i)
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set @i=@i+1 >V$#Um?AXj
end c\'pA^m6
小记存储过程中经常用到的本周,本月,本年函数 R
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Dateadd(wk,datediff(wk,0,getdate()),-1) Tz-cN
Dateadd(wk,datediff(wk,0,getdate()),6) k$ M4NF~$
Dateadd(mm,datediff(mm,0,getdate()),0) M0e|G.S&_
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) I7_D $a=
Dateadd(yy,datediff(yy,0,getdate()),0) j)DZmGg&t
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <`*P/V
上面的SQL代码只是一个时间段 Os!22 O
Dateadd(wk,datediff(wk,0,getdate()),-1) >z
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Dateadd(wk,datediff(wk,0,getdate()),6) oMe]dK
就是表示本周时间段. XOwMT,=Z)
下面的SQL的条件部分,就是查询时间段在本周范围内的: T6r~OV5
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Kzu9Qm-+z^
而在存储过程中 NKKOA
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) b
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ko>_@]Jb