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。 p
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一、基础 \
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1、说明:创建数据库 ?s"v0cg+
CREATE DATABASE database-name $=m17GD
2、说明:删除数据库 RLHe;-*b]I
drop database dbname IfXLnD^||
3、说明:备份sql server fF[ g%?w
--- 创建 备份数据的 device rw\4KI@ L
USE master t2Y~MyT/
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' j'J*QK&Q
--- 开始 备份 'qd")
BACKUP DATABASE pubs TO testBack 4COf H7Al9
4、说明:创建新表 .RWBn~b#I
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }\*Sf[EMD
根据已有的表创建新表: "\=_- `
A:create table tab_new like tab_old (使用旧表创建新表) !yI)3;$*
B:create table tab_new as select col1,col2... from tab_old definition only .yP
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5、说明:删除新表 QF>[cdl?8
drop table tabname w9PY^U.Y3e
6、说明:增加一个列 7z,M`14
Alter table tabname add column col type u ?Xku8 1l
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。 O46/[{p+8
7、说明:添加主键: Alter table tabname add primary key(col) Fszk?0T
说明:删除主键: Alter table tabname drop primary key(col) 6e*b;{d
8、说明:创建索引:create [unique] index idxname on tabname(col....) ,/ : )FV
删除索引:drop index idxname vxt^rBA
注:索引是不可更改的,想更改必须删除重新建。 |5/[0V-vy
9、说明:创建视图:create view viewname as select statement n{yjH*\Z
删除视图:drop view viewname *sG<w%%
10、说明:几个简单的基本的sql语句 -/qrEKQ0U?
选择:select * from table1 where 范围 FTenXJ/c
插入:insert into table1(field1,field2) values(value1,value2) dCK-"#T!
删除:delete from table1 where 范围 HY:@=%R
更新:update table1 set field1=value1 where 范围 |#B"j1D,H
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 7A|jnm
排序:select * from table1 order by field1,field2 [desc] 4>E2G:
总数:select count as totalcount from table1 t;1NzI$^
求和:select sum(field1) as sumvalue from table1 ~GeYB6F
平均:select avg(field1) as avgvalue from table1 ,'673PR
最大:select max(field1) as maxvalue from table1 FS}z_G|4]
最小:select min(field1) as minvalue from table1 )-{Qa\6(%
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11、说明:几个高级查询运算词 7| T:TbY>
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HW G~m:km
A: UNION 运算符 S_CtEM
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 .-ABo]hf
B: EXCEPT 运算符 Dn3~8
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 V"ZbKV+[
C: INTERSECT 运算符 p o`$^TB^+
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。 yBj)#m5!
注:使用运算词的几个查询结果行必须是一致的。 f.$o|R=v
12、说明:使用外连接 K?je(t^
A、left outer join: -DnK)u\@
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 u3:Q t2^S
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [mPdT^h
B:right outer join: ,f+5x]F?m
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 w0!,1
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C:full outer join: N96BWgT
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 z{d5Lrk
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二、提升 Fzs'@*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) U;GoC$b}|
法一:select * into b from a where 1<>1 jZ!JXmVV
法二:select top 0 * into b from a eLny-.i,7
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 0Y2^}u@5
insert into b(a, b, c) select d,e,f from b; [BBKj)IK
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) F/SsiUBS
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Cpcd`y=IN
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 0AKwZ'
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4、说明:子查询(表名1:a 表名2:b) E3skC%}
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) |mmG
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5、说明:显示文章、提交人和最后回复时间 61/zrMPn
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8!GLw-kb
6、说明:外连接查询(表名1:a 表名2:b) H|U/tU-
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ..!-)q'?
7、说明:在线视图查询(表名1:a ) X^5"7phI@
select * from (SELECT a,b,c FROM a) T where t.a > 1; ? myXG92
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 CJixK>Y^
select * from table1 where time between time1 and time2 ZD%_PgiT
select a,b,c, from table1 where a not between 数值1 and 数值2 _%vqBr*
9、说明:in 的使用方法 +[/r^C
select * from table1 where a [not] in ('值1','值2','值4','值6') NCFV
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >}{-!
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Td1ba ^J
11、说明:四表联查问题: *v ^"4
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 ..... Sp,Q,Q4
12、说明:日程安排提前五分钟提醒 _vV&4>
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 M%s$F@
13、说明:一条sql 语句搞定数据库分页 FraW6T}_
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 f<:U"E.
14、说明:前10条记录 vfUfrk@D~
select top 10 * form table1 where 范围 /2Lo{v=0[
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.) V )k, 9=
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /^3oq]
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 :wZ`>,K"t>
(select a from tableA ) except (select a from tableB) except (select a from tableC) 2^#UO=ct
17、说明:随机取出10条数据 ?_>^<1I1
select top 10 * from tablename order by newid() Ygi1"X}
18、说明:随机选择记录 [Cqqjv;_
select newid() pptM&Y
19、说明:删除重复记录 MlK`sH6
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) zWs*kTtA
20、说明:列出数据库里所有的表名 .*~u
select name from sysobjects where type='U' /cC6qhkp%
21、说明:列出表里的所有的 YOV4)P"
select name from syscolumns where id=object_id('TableName') E97+GJ3
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。 h<1dTl*
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 $7&l6~sMQ
显示结果: 5f'g3'
type vender pcs |8c:+8
电脑 A 1 prEu9$:t
电脑 A 1 8J3@VD.
光盘 B 2 V9j1j}
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光盘 A 2 Tj21YK.mk
手机 B 3 ~]W[ {3 ;
手机 C 3 O| J`~Lk
23、说明:初始化表table1 u] U)d$|
TRUNCATE TABLE table1 9jR[:[
24、说明:选择从10到15的记录 8$v zpu
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 2\63&C^
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三、技巧 =ym
1、1=1,1=2的使用,在SQL语句组合时用的较多 4^[}]'w
"where 1=1" 是表示选择全部 "where 1=2"全部不选, aaz"`,7_
如: A!W"*WT
if @strWhere !='' \q|7,S,5
begin (#B^Hyz!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 6{ +_T
end }u-S j/K
else lIVxW+
begin w"a 9'r
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' hK39_A-
end xw+<p
我们可以直接写成 Km9}^*Mo%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere =Esbeb7P
2、收缩数据库 ri<'-w i
--重建索引 S -6"f/
DBCC REINDEX te;Ox!B&
DBCC INDEXDEFRAG jemxky
--收缩数据和日志 BLwfm+ m"
DBCC SHRINKDB a#Kmj0
DBCC SHRINKFILE S@c\|
3、压缩数据库 x'2 ,sE
dbcc shrinkdatabase(dbname) 4" ,
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4、转移数据库给新用户以已存在用户权限 7.$]f71z
exec sp_change_users_login 'update_one','newname','oldname' 1]>$5 1Q
go eyf4M;goz}
5、检查备份集 /~Zc}o,J
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' OgKWgvy
6、修复数据库 <+\k&W&Y|y
ALTER DATABASE [dvbbs] SET SINGLE_USER ~TG39*m
GO a*6wSAA )
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK R 5K-KSvW
GO u%=bHg
ALTER DATABASE [dvbbs] SET MULTI_USER niYz9YX
GO bk7^%O>
7、日志清除 &gWMl`3^*!
SET NOCOUNT ON @TA8^ND
DECLARE @LogicalFileName sysname, JN&MyA"
@MaxMinutes INT, m)@Q_{=6M
@NewSize INT Mr=}B6`
USE tablename -- 要操作的数据库名 K5!";V
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 3s?v(1 {)
@MaxMinutes = 10, -- Limit on time allowed to wrap log. _b0S
@NewSize = 1 -- 你想设定的日志文件的大小(M) m|[\F#+C
-- Setup / initialize p;qRm}
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DECLARE @OriginalSize int JlC<MQ?
SELECT @OriginalSize = size N
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FROM sysfiles GB<R7J
WHERE name = @LogicalFileName n5bXQ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + *MYt:ms
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + WYwzo V-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' e86Aqehle
FROM sysfiles pXPqDA
WHERE name = @LogicalFileName |?x^8e<*
CREATE TABLE DummyTrans j`2B}@ 2
(DummyColumn char (8000) not null) [as-3&5S
DECLARE @Counter INT, uX[O,l^}
@StartTime DATETIME, 0\5M^:8i3
@TruncLog VARCHAR(255) g|ql 5jW
SELECT @StartTime = GETDATE(), FNz84qVIx'
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' YO@hE>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) n 5~=qQK2
EXEC (@TruncLog) CgVh\4,a
-- Wrap the log if necessary. <\, &:<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired UvPp~N7,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) gf0PMc3l
AND (@OriginalSize * 8 /1024) > @NewSize /:#j?c
BEGIN -- Outer loop. PM~bM3Ei
SELECT @Counter = 0 OlEpid'Z
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 2;~KL-h0TK
BEGIN -- update \|4 Ca't
INSERT DummyTrans VALUES ('Fill Log') 99F>n[5
DELETE DummyTrans 4@DVc7\x$
SELECT @Counter = @Counter + 1 X$Q2m{dR
END B;eW/#`
EXEC (@TruncLog) x8 f6,
END pNp^q/-yB
SELECT 'Final Size of ' + db_name() + ' LOG is ' + J3H.%m!V
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + KU+( YF$1
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' d@-wi%,^
FROM sysfiles YO)')&
WHERE name = @LogicalFileName Sdgb#?MR|
DROP TABLE DummyTrans %S{o5txo
SET NOCOUNT OFF nHSTeFI?
8、说明:更改某个表 uDILjOT
exec sp_changeobjectowner 'tablename','dbo' {B@*DQv
9、存储更改全部表 \4OK!6LkI
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ]KsGkAG
@OldOwner as NVARCHAR(128), -&trk
@NewOwner as NVARCHAR(128) mYX56,b}5
AS pz$_W
DECLARE @Name as NVARCHAR(128) ER{yuw
DECLARE @Owner as NVARCHAR(128) hgj CXl
DECLARE @OwnerName as NVARCHAR(128) DXKyRkn6e
DECLARE curObject CURSOR FOR EtGH\?d~]
select 'Name' = name, a|UqeNI{
'Owner' = user_name(uid) --Oprl
from sysobjects gk"mr_03
where user_name(uid)=@OldOwner D2Y&[zgv
order by name F
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OPEN curObject `Gf{z%/
FETCH NEXT FROM curObject INTO @Name, @Owner SLSF
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WHILE(@@FETCH_STATUS=0) GL/ KB
BEGIN /a%*u6z@
if @Owner=@OldOwner 9QX4R<"wUg
begin [d0%.+U
set @OwnerName = @OldOwner + '.' + rtrim(@Name) DK)u)?!
exec sp_changeobjectowner @OwnerName, @NewOwner Fl<(m
end bpGzTU
-- select @name,@NewOwner,@OldOwner HP;|'b
FETCH NEXT FROM curObject INTO @Name, @Owner VR"8Di&)
END MM7"a?y)
close curObject s}jlS
deallocate curObject 1sD~7KPg?
GO #
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10、SQL SERVER中直接循环写入数据 PDhWFF
declare @i int r9?o$=T
set @i=1 n-d:O\]
while @i<30 NNgK:YibD
begin @Eo4U]-
insert into test (userid) values(@i) kr#I{gF
set @i=@i+1 6?O}Q7G
end Ex6o=D2
小记存储过程中经常用到的本周,本月,本年函数 C]/&vh7ta
Dateadd(wk,datediff(wk,0,getdate()),-1) rrAqI$6
Dateadd(wk,datediff(wk,0,getdate()),6) &T7cH>E'K^
Dateadd(mm,datediff(mm,0,getdate()),0) ^=k{~
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) O5O.><RP
Dateadd(yy,datediff(yy,0,getdate()),0) q=njKC
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) V+46R
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上面的SQL代码只是一个时间段 mzu<C)9d,
Dateadd(wk,datediff(wk,0,getdate()),-1) bhn5Lz$z
Dateadd(wk,datediff(wk,0,getdate()),6) |Hfl&3
就是表示本周时间段. qT$)Rb&
下面的SQL的条件部分,就是查询时间段在本周范围内的: $}db /hY*
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 5.dl>,
而在存储过程中 KhrFg1|
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ER_ 3'
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) b )Tl*