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。 +%YBa'Lk
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一、基础 s|WwBT
1、说明:创建数据库 P] *x6c^n
CREATE DATABASE database-name U>lf-iI2B
2、说明:删除数据库 8)>x) T
drop database dbname @ZU$W9g
3、说明:备份sql server 9:p-F+
--- 创建 备份数据的 device Aax;0qGbH
USE master l~"T>=jq3
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' SAdT#0J
--- 开始 备份 Imv#7{ndq
BACKUP DATABASE pubs TO testBack @$jV"Y
4、说明:创建新表 y.lWyH9
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) |OJWQU![by
根据已有的表创建新表: (=^KP7
A:create table tab_new like tab_old (使用旧表创建新表) WnG2\(U
B:create table tab_new as select col1,col2... from tab_old definition only qm$(_]R~`
5、说明:删除新表 $A?9U}V#^
drop table tabname ,jRAVt+{N
6、说明:增加一个列 nsI+04[F
Alter table tabname add column col type Mw0>p5+ cy
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 o*)Sg6Yk
7、说明:添加主键: Alter table tabname add primary key(col) y nmjIQ
说明:删除主键: Alter table tabname drop primary key(col) -
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8、说明:创建索引:create [unique] index idxname on tabname(col....) p?f\/
删除索引:drop index idxname [uU!\xe
注:索引是不可更改的,想更改必须删除重新建。 }O*`I(
9、说明:创建视图:create view viewname as select statement @?<[//1
删除视图:drop view viewname T)gulP
10、说明:几个简单的基本的sql语句 ^7yt>
选择:select * from table1 where 范围 3`cA!ZVQ
插入:insert into table1(field1,field2) values(value1,value2) GCJ[x n(_
删除:delete from table1 where 范围 srf}+>u&
更新:update table1 set field1=value1 where 范围 u0L-xC$L
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! YTa
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排序:select * from table1 order by field1,field2 [desc] ^($'l)I
总数:select count as totalcount from table1 xuvW6Q;
求和:select sum(field1) as sumvalue from table1 G{!er:Vwdh
平均:select avg(field1) as avgvalue from table1 jTR?!Mt0
最大:select max(field1) as maxvalue from table1 D#LV&4e>.E
最小:select min(field1) as minvalue from table1 YJv$,Z&;HO
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11、说明:几个高级查询运算词 eMRH*MyD
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A: UNION 运算符 Nhs!_-_I
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。 dLp1l2h!0
B: EXCEPT 运算符 tfU*U>j
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。 o=YOn&@%
C: INTERSECT 运算符 M?lh1Yu"
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。 }R}+8
注:使用运算词的几个查询结果行必须是一致的。 U=bx30brh%
12、说明:使用外连接 >SI'Q7k
A、left outer join: M,fL(b;2
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。 n.+'9Fj
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 wS}c\!@<,
B:right outer join: o^/
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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。 | @AXW
C:full outer join: X6cn8ak3
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。 V^,gpTyv*
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二、提升 J.yM@wPS>
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) w1G(s$;C
法一:select * into b from a where 1<>1 T2Yf7Szp
法二:select top 0 * into b from a ?CAU+/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) [1vm~w'
insert into b(a, b, c) select d,e,f from b; g.&B8e
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) Q!P%duO
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6axxyh%
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \!\:p/f
4、说明:子查询(表名1:a 表名2:b) Bg]VaTm[=
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) Ow4 _0l&
5、说明:显示文章、提交人和最后回复时间 -LiGO #U
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Jb"FY:/Qv+
6、说明:外连接查询(表名1:a 表名2:b) R@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 D<J'\mo
7、说明:在线视图查询(表名1:a ) 8lV:-"+5
select * from (SELECT a,b,c FROM a) T where t.a > 1; t.ulG
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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 M>i(p%
select * from table1 where time between time1 and time2 NTt4sWP!I
select a,b,c, from table1 where a not between 数值1 and 数值2 ipn-HUrE@
9、说明:in 的使用方法 DDr\Kv)k(
select * from table1 where a [not] in ('值1','值2','值4','值6') VwI
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .~o{i_JH
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) eaFkDl
11、说明:四表联查问题: 2V@5:tf
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 ..... *5PQ>d
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12、说明:日程安排提前五分钟提醒 naaKAZ!S
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 |<c9ZS+
13、说明:一条sql 语句搞定数据库分页 ,7s>#b'
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 w<H Xe
14、说明:前10条记录 qO"QSSbZqQ
select top 10 * form table1 where 范围 G^ GIHdo
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.) U(f@zGV
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) iW6O9~
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 ?1ey$SSU]
(select a from tableA ) except (select a from tableB) except (select a from tableC) `NQ
17、说明:随机取出10条数据 futYMoV
select top 10 * from tablename order by newid() #1%@R<`
18、说明:随机选择记录 Sl8+A+
select newid() BHY-fb@R]H
19、说明:删除重复记录 MZ"V\6T]
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 6>)fNCe`
20、说明:列出数据库里所有的表名 h A ){>B<;
select name from sysobjects where type='U' o:#jvi84F
21、说明:列出表里的所有的 eF%M2:&c;
select name from syscolumns where id=object_id('TableName') B[ZQn]y
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。 &^$@LH3
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type PaSwfjOnqr
显示结果: MQP9^+f)O?
type vender pcs :\~>7VFg
电脑 A 1 Doc zQc-U+
电脑 A 1 :z8/iD y
光盘 B 2 zh2<!MH
光盘 A 2 f$>_>E
手机 B 3 q(qm3OxYo
手机 C 3 c= t4 gf
23、说明:初始化表table1 C?|sQcCE
TRUNCATE TABLE table1 }p?,J8=-
24、说明:选择从10到15的记录 l?)>"^
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ahXcQ9jzFi
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三、技巧 "#E
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1、1=1,1=2的使用,在SQL语句组合时用的较多 m^oG9&";
"where 1=1" 是表示选择全部 "where 1=2"全部不选, LhAN( [
如: K ar!
if @strWhere !='' F qJ`d2E
begin V30w`\1A
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere o*204BGB
end uM$b/3%s
else j(y<oxh
begin #MYoy7=
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' i]<@
end m u9,vH
我们可以直接写成 fL|9/sojz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Ct `)R
2、收缩数据库 O h
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--重建索引 FZgf"XM>
DBCC REINDEX Zw)=Y.y!
DBCC INDEXDEFRAG )vq}$W!:9
--收缩数据和日志 HBp??.r
DBCC SHRINKDB Dl.<(/
DBCC SHRINKFILE Vb?wwx7=
3、压缩数据库 dXDyY
dbcc shrinkdatabase(dbname) q2xAx1R`sV
4、转移数据库给新用户以已存在用户权限 <,DMD
exec sp_change_users_login 'update_one','newname','oldname' t?&;
go aO$0[-A
5、检查备份集 +On2R&m
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' imADjBR]
6、修复数据库 A@~9r9Uf
ALTER DATABASE [dvbbs] SET SINGLE_USER pzRVX8
GO IsT}T}p,t
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Uhvy2}w
GO :Jyr^0`J
ALTER DATABASE [dvbbs] SET MULTI_USER Pm P&Qje7
GO GdC=>\]
7、日志清除 <!t;[ie?y
SET NOCOUNT ON !QdX+y<re
DECLARE @LogicalFileName sysname, t~qSiHw
@MaxMinutes INT, 5xr2
@NewSize INT c@,1?q1bv
USE tablename -- 要操作的数据库名 Fdl0V:<
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 F$i50s
@MaxMinutes = 10, -- Limit on time allowed to wrap log. WS&a9!3;
@NewSize = 1 -- 你想设定的日志文件的大小(M) V+y|C[A
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-- Setup / initialize y=9fuGL6
DECLARE @OriginalSize int 9+(6/<
SELECT @OriginalSize = size Ox
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FROM sysfiles [.l,#-vp
WHERE name = @LogicalFileName Y|mtQE?c
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 0;a1 0b
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + !JdZ0l
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' e lM<S3
FROM sysfiles UHV"<9tk
WHERE name = @LogicalFileName \gT({XU?
CREATE TABLE DummyTrans q !}~c
(DummyColumn char (8000) not null) vZQraY nJ
DECLARE @Counter INT, R,.qQF\*
@StartTime DATETIME, O\q6T7bfRW
@TruncLog VARCHAR(255) !*DYdqQ/
SELECT @StartTime = GETDATE(), M.SF}U
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 0XljFQ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) .`KzA]
EXEC (@TruncLog) %a8e_
-- Wrap the log if necessary. w?_'sP{pd
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired pbh>RS=ri
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) rLeQBp'
AND (@OriginalSize * 8 /1024) > @NewSize 43=)akJi
BEGIN -- Outer loop. YpZuAJm<2_
SELECT @Counter = 0 ~W"@[*6w
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `<@ "WSn
BEGIN -- update L5:1dF
INSERT DummyTrans VALUES ('Fill Log') i%i s<'
DELETE DummyTrans v\(6uej^
SELECT @Counter = @Counter + 1 +bso4 }rS
END fM&
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EXEC (@TruncLog) ) F -8
END Wt5pK[JV
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Z1$S(p=)L
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2ETv H~23
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' MYJMZ3qBi
FROM sysfiles ?W dY{;&
WHERE name = @LogicalFileName KWYjN
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DROP TABLE DummyTrans 3it*l-i\
SET NOCOUNT OFF \u6.*w5TI
8、说明:更改某个表 q(46v`u
exec sp_changeobjectowner 'tablename','dbo'
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9、存储更改全部表 Kl ?C[
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch w$]wd`N}
@OldOwner as NVARCHAR(128), A]%*ye"NT
@NewOwner as NVARCHAR(128) 4QC_zyTE
AS 1D1kjM^Bo
DECLARE @Name as NVARCHAR(128) 8YPX8d8u
DECLARE @Owner as NVARCHAR(128) mxH63$R
DECLARE @OwnerName as NVARCHAR(128) LGtw4'yr
DECLARE curObject CURSOR FOR ijcF[bmE
select 'Name' = name, K{Nj-Rqd
'Owner' = user_name(uid) mDt!b6N/
from sysobjects ]#S<]v A
where user_name(uid)=@OldOwner TrgKl2xfx
order by name m1K4_a)^[
OPEN curObject hBz>E 4mEv
FETCH NEXT FROM curObject INTO @Name, @Owner .i;?8?
WHILE(@@FETCH_STATUS=0) Dg Rn^gL{Q
BEGIN a&kt!%p:
if @Owner=@OldOwner B$OV^iwxK
begin 4F -<j!
set @OwnerName = @OldOwner + '.' + rtrim(@Name) $Ups9p Q
exec sp_changeobjectowner @OwnerName, @NewOwner xqDz*V/mD
end CG35\b;Q
-- select @name,@NewOwner,@OldOwner ;xFB
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FETCH NEXT FROM curObject INTO @Name, @Owner /A>nsN?:]
END 6c>:h)?
close curObject <RbsQ^U
deallocate curObject ^VnnYtCRz
GO .|P
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10、SQL SERVER中直接循环写入数据 S%?%06$
declare @i int I~HA
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set @i=1 Yp3 y%n
while @i<30 #l* w=D?
begin M)JozD%
insert into test (userid) values(@i) Ag{)?5/d_
set @i=@i+1 $E8}||d
end +~==qLsU
小记存储过程中经常用到的本周,本月,本年函数 :"nh76xg<
Dateadd(wk,datediff(wk,0,getdate()),-1) A58P$#)?
Dateadd(wk,datediff(wk,0,getdate()),6) IW}Wt{'m
Dateadd(mm,datediff(mm,0,getdate()),0) @eESKg(,
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) jW^]N$>
Dateadd(yy,datediff(yy,0,getdate()),0) ww+,GnV
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) A&ceuu
上面的SQL代码只是一个时间段 Rb^G~82d?
Dateadd(wk,datediff(wk,0,getdate()),-1) sw:a(o&$
Dateadd(wk,datediff(wk,0,getdate()),6) m.gv?
就是表示本周时间段. ; Ob^@OM
下面的SQL的条件部分,就是查询时间段在本周范围内的: ]W`M
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8F$]@0v`%
而在存储过程中 }QCn>LXE
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Jh4pY#aF
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) gL@]p