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。 vX"*4m>b?+
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一、基础 @ioJ]$o7
1、说明:创建数据库 U&OJXJdj
CREATE DATABASE database-name 6l1jMm|=
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2、说明:删除数据库 wo/\]5
drop database dbname #x60xz
3、说明:备份sql server ! E5HN :#
--- 创建 备份数据的 device }C?'BRX
USE master <2x^slx)?
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' itP,\k7>d
--- 开始 备份 R|, g<
BACKUP DATABASE pubs TO testBack >T-u~i$s
4、说明:创建新表 -f^tE,-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) b\!_cb~ "@
根据已有的表创建新表: ie95rZp
A:create table tab_new like tab_old (使用旧表创建新表) o#Dk&
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B:create table tab_new as select col1,col2... from tab_old definition only "Gzz4D
5、说明:删除新表 ZvX*t)VjTz
drop table tabname _ <V)-Y
6、说明:增加一个列 I;(L%TT `
Alter table tabname add column col type |aS.a&vwR
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。 B dfwa
7、说明:添加主键: Alter table tabname add primary key(col) Iyn(?w
说明:删除主键: Alter table tabname drop primary key(col) !>o7a}?
8、说明:创建索引:create [unique] index idxname on tabname(col....) G>}255qY
删除索引:drop index idxname ;ef}}K
注:索引是不可更改的,想更改必须删除重新建。 U< fGGCw
9、说明:创建视图:create view viewname as select statement *:7rdzn
删除视图:drop view viewname O8r|8]o
10、说明:几个简单的基本的sql语句 K@]4g49A/j
选择:select * from table1 where 范围 `/+>a8
插入:insert into table1(field1,field2) values(value1,value2) adcE'fA<_
删除:delete from table1 where 范围 {}przrU^c
更新:update table1 set field1=value1 where 范围 Bkc4TO
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! +\]\[6
排序:select * from table1 order by field1,field2 [desc] ;H*T^0
总数:select count as totalcount from table1 K5h
求和:select sum(field1) as sumvalue from table1 _jVN&\A]mC
平均:select avg(field1) as avgvalue from table1 F/{!tx
最大:select max(field1) as maxvalue from table1 ?l{nk5,?-Y
最小:select min(field1) as minvalue from table1 |HQW0
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11、说明:几个高级查询运算词 cuITY^6
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A: UNION 运算符 dZ@63a>>@
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。 [9L:),&u
B: EXCEPT 运算符 LEdh!</'24
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。 C,r;VyW6BI
C: INTERSECT 运算符 p6V0`5@t
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。 g3y~bf
注:使用运算词的几个查询结果行必须是一致的。 g!|kp?
12、说明:使用外连接 Lqa4Vi
A、left outer join: J
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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。 6bC3O4Rw
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 r,p%U!S<hV
B:right outer join: a1lh-2xX
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。 4D4j7
C:full outer join: _Fl9>C"u
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。 }Sv:`9=
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二、提升 /U9"wvg
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) #"~<HG}bR/
法一:select * into b from a where 1<>1 F JyT+
法二:select top 0 * into b from a sO@Tf\d
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) B]tQ(s~
insert into b(a, b, c) select d,e,f from b; ~]2K^bh8&
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) + ePS14G
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 kxv1Hn"`{E
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. YaqJ,"GlT
4、说明:子查询(表名1:a 表名2:b) 7kEn \
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) \4fQMG
5、说明:显示文章、提交人和最后回复时间 5.GR1kl6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 'H;*W |:-]
6、说明:外连接查询(表名1:a 表名2:b) evmeqQG=
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Avb\{)s+
7、说明:在线视图查询(表名1:a ) '`Hr}
select * from (SELECT a,b,c FROM a) T where t.a > 1;
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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 <LiPEo.R
select * from table1 where time between time1 and time2 #ABZ&Z
select a,b,c, from table1 where a not between 数值1 and 数值2 tR$NRMZ.
9、说明:in 的使用方法 i/Zd8+.n$
select * from table1 where a [not] in ('值1','值2','值4','值6') -iZ`Y?
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3Y$GsN4ln
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Q$"D]!G
11、说明:四表联查问题: FYQS)s
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 ..... ;2QP7PrSY
12、说明:日程安排提前五分钟提醒 T>W,'H
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]Y&VT7+Z
13、说明:一条sql 语句搞定数据库分页 +ZP7{%
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 i83OOV$1J
14、说明:前10条记录 f/?P514h
select top 10 * form table1 where 范围 r~['VhI!;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.) sW\!hW1*x
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) S_H+WfIHV'
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 RViAwTvY
(select a from tableA ) except (select a from tableB) except (select a from tableC) pQB."[n
17、说明:随机取出10条数据 (ToUgVW1N
select top 10 * from tablename order by newid() xAm6BB
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18、说明:随机选择记录 Ny/MJ#Lq
select newid() $F.a><1rY
19、说明:删除重复记录
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) dM@1l1h/
20、说明:列出数据库里所有的表名 J{G?-+`
select name from sysobjects where type='U' A04U /;
21、说明:列出表里的所有的 q)
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select name from syscolumns where id=object_id('TableName') !&E-}}<
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 W(p_.p"
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Ow,b^|
显示结果: 8z\xrY
type vender pcs j?QDR
电脑 A 1 J'r^/
电脑 A 1 8u]2xB=K
光盘 B 2 F!K>K z
光盘 A 2 lyhiFkO
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手机 B 3 _aeBauD
手机 C 3 COlaD"Y
23、说明:初始化表table1 'J|_2*
TRUNCATE TABLE table1 MolgwVd
24、说明:选择从10到15的记录 )+Pus~w
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5"H=zJ=r
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三、技巧 %;!.n{X
1、1=1,1=2的使用,在SQL语句组合时用的较多 \_f v7Fdp{
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |y!A&d=xYn
如: ,/unhfs1q
if @strWhere !='' DtnEi4h,
begin ],].zlN
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Znv,9-
end %&bY]w
else gBD]}vo-
begin *X}`PF
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' sDV Q#}a
end OZ;*JR:
我们可以直接写成 g9F?z2^
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ddR>7d}N
2、收缩数据库 Ek}A]zC
--重建索引 d'sZxU
DBCC REINDEX +"VP-s0
DBCC INDEXDEFRAG [Vt\$
--收缩数据和日志 SgOheN-
DBCC SHRINKDB i}?>g -(
DBCC SHRINKFILE 9&NgtZpt
3、压缩数据库 :BTq!>s
dbcc shrinkdatabase(dbname) {(}By/_
4、转移数据库给新用户以已存在用户权限 &+R?_Ooibk
exec sp_change_users_login 'update_one','newname','oldname' [0e_*
go ct}9i"H#1
5、检查备份集 GPkpXVm
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 40
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6、修复数据库 J$v?T$LVw
ALTER DATABASE [dvbbs] SET SINGLE_USER PFK
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GO _J [P[(ab
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK WjqO@]P6
GO >F&47Yn
ALTER DATABASE [dvbbs] SET MULTI_USER >&k-'`Nw
GO ^Zp>G{QL{
7、日志清除 *uvQ\.
SET NOCOUNT ON _<2E"PrT
DECLARE @LogicalFileName sysname, 7=, ; h
@MaxMinutes INT, 29q _BR *:
@NewSize INT E1 f\%!2l
USE tablename -- 要操作的数据库名 ~y[7K{{ ;T
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 WMP,\=6k0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. @xZR9Z8]L
@NewSize = 1 -- 你想设定的日志文件的大小(M) xn|(9#1o
-- Setup / initialize BFW&2
DECLARE @OriginalSize int }4S6Xe
SELECT @OriginalSize = size jlg(drTo
FROM sysfiles ei5~&
WHERE name = @LogicalFileName uRe'%?W
SELECT 'Original Size of ' + db_name() + ' LOG is ' + T9q-,w/j;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + sUm'
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' gv{ >`AN
FROM sysfiles .w,q0<}
WHERE name = @LogicalFileName S#[j )U-
CREATE TABLE DummyTrans Fea(zJ_
(DummyColumn char (8000) not null) G9@0@2aY8
DECLARE @Counter INT, wn)W
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@StartTime DATETIME, sFTy(A/
@TruncLog VARCHAR(255) VOh4#%Vj
SELECT @StartTime = GETDATE(), $xdy&
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :T(|&F[(
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $
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EXEC (@TruncLog) -C&P%tt Y
-- Wrap the log if necessary. m9}P9?
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired B^jc3 VsR
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8kDp_si
AND (@OriginalSize * 8 /1024) > @NewSize 9]o-O]7/
BEGIN -- Outer loop. , SnSW-P
SELECT @Counter = 0 *siFj
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ;mKb]
BEGIN -- update dN[\xVcj
INSERT DummyTrans VALUES ('Fill Log') t.\dpBq
DELETE DummyTrans 0S$N05
SELECT @Counter = @Counter + 1 =zs`#-^8
END _/<x
EXEC (@TruncLog) j^2j&Ta
END {+Cy U!O
SELECT 'Final Size of ' + db_name() + ' LOG is ' + QoH6
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + @49S`
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' KRKCD4
FROM sysfiles d9|<@A
WHERE name = @LogicalFileName .Rf_Cl
DROP TABLE DummyTrans %3''}Y5
SET NOCOUNT OFF P J[`|
8、说明:更改某个表 'a.qu9PJ
exec sp_changeobjectowner 'tablename','dbo' 2Q:+_v
9、存储更改全部表 ^&Y#)II
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ~2khgZ
@OldOwner as NVARCHAR(128), 0% I=d
@NewOwner as NVARCHAR(128) @>H75
AS ,UdVNA
DECLARE @Name as NVARCHAR(128) 4x[S\,20
DECLARE @Owner as NVARCHAR(128) !brf(-sr)
DECLARE @OwnerName as NVARCHAR(128) ZO$%[ftb
DECLARE curObject CURSOR FOR jdJ>9O0A,
select 'Name' = name, R]*K:~DM
'Owner' = user_name(uid) SGlNKA},A
from sysobjects KL Xq\{X
where user_name(uid)=@OldOwner [0D.K}7|
order by name ijx0gh`~
OPEN curObject 0>Z_*U~6
FETCH NEXT FROM curObject INTO @Name, @Owner *%@h(js
WHILE(@@FETCH_STATUS=0) =+d?x56
BEGIN 2*#|Nj=^
if @Owner=@OldOwner sZF6h=67D
begin <0q;NrvUb
set @OwnerName = @OldOwner + '.' + rtrim(@Name) by/jYg)+
exec sp_changeobjectowner @OwnerName, @NewOwner Hc(OI|z~
end kt$jm)UI~l
-- select @name,@NewOwner,@OldOwner XACm[NY_
FETCH NEXT FROM curObject INTO @Name, @Owner ]- QA'Lq
END x0:m-C
close curObject e'b(gD}
deallocate curObject W-zP/]Dh
GO mF^v ~
10、SQL SERVER中直接循环写入数据 N^:9Fz
declare @i int %&t<K3&Yh
set @i=1 !f&g-V
while @i<30 @/-\k*T
begin G{%L B}2
insert into test (userid) values(@i) b(O3@Q6[
set @i=@i+1 y:qUn!3
end w}cPs{Vi"
小记存储过程中经常用到的本周,本月,本年函数 j]/RC(;?
Dateadd(wk,datediff(wk,0,getdate()),-1) d)f :)Ew
Dateadd(wk,datediff(wk,0,getdate()),6) [RTs[3E^
Dateadd(mm,datediff(mm,0,getdate()),0) =P
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Aj+F
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Dateadd(yy,datediff(yy,0,getdate()),0) d <JM36j?
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :1KpGj*F
上面的SQL代码只是一个时间段 (,Df^4%7
Dateadd(wk,datediff(wk,0,getdate()),-1) <
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Dateadd(wk,datediff(wk,0,getdate()),6) C/6V9;U
就是表示本周时间段. :'*~uJrR
下面的SQL的条件部分,就是查询时间段在本周范围内的: D]Xsvv
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 55c|O
而在存储过程中 w%BL
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) M} v/tRI
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |64~K\X