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。 4q] 6[/
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一、基础 8
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1、说明:创建数据库 q~> +x?30
CREATE DATABASE database-name m:)&:Y0 (a
2、说明:删除数据库 n8Qv8
drop database dbname m,\+RUW'
3、说明:备份sql server 2p, U ^h
--- 创建 备份数据的 device rEWJ3*Hb
USE master H[.)&7M\
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %@C8EFl%3
--- 开始 备份 I^A>YJW
BACKUP DATABASE pubs TO testBack *>W<n1r@]
4、说明:创建新表 nV8'QDQ:Al
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) q!Ek
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根据已有的表创建新表: 7<WUjK|
A:create table tab_new like tab_old (使用旧表创建新表) e;XRH<LhAU
B:create table tab_new as select col1,col2... from tab_old definition only gf>H-718F
5、说明:删除新表 Ct-eD-X{
drop table tabname [j/|)cj
6、说明:增加一个列 15jQ87)
Alter table tabname add column col type +&7V@
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。 H(;@7dh
7、说明:添加主键: Alter table tabname add primary key(col) ^|Z'}p|&
说明:删除主键: Alter table tabname drop primary key(col) O=bkq}
8、说明:创建索引:create [unique] index idxname on tabname(col....) yJ!26
删除索引:drop index idxname #$W5)6ch
注:索引是不可更改的,想更改必须删除重新建。 gN<7(F
9、说明:创建视图:create view viewname as select statement G AY?F
删除视图:drop view viewname nmiJ2edx
10、说明:几个简单的基本的sql语句 Ydrh+
选择:select * from table1 where 范围 ?S&
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插入:insert into table1(field1,field2) values(value1,value2) ^^}htg
删除:delete from table1 where 范围 _}[WX[Le{
更新:update table1 set field1=value1 where 范围 2
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ^&&Wv'7XQ
排序:select * from table1 order by field1,field2 [desc] e^N~)Nlj
总数:select count as totalcount from table1 >8{w0hh;
求和:select sum(field1) as sumvalue from table1 +PE-j| D
平均:select avg(field1) as avgvalue from table1 H^kOwmSzh
最大:select max(field1) as maxvalue from table1 <b"^\]l
最小:select min(field1) as minvalue from table1 *
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11、说明:几个高级查询运算词 EoutB Vm
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A: UNION 运算符 u:J(0re
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。 Ju#j%!
B: EXCEPT 运算符 &i3SB[|
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。 %?n=In(F
C: INTERSECT 运算符 .*6NqX$
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。 @nwVl8
注:使用运算词的几个查询结果行必须是一致的。 }ACg#;>/+
12、说明:使用外连接 6, j60`f)
A、left outer join: V?yQm4
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。 <LH6my
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 <=_!8A
B:right outer join: wM[Z 0*K
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。 82 |^o
C:full outer join:
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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。 >a*dI_XE
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二、提升 HABUf^~-
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) sKW~+]
法一:select * into b from a where 1<>1 2?LPr
法二:select top 0 * into b from a /zh:7N
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 4E=QO!pVv
insert into b(a, b, c) select d,e,f from b; l#C<bDw
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) Z2*?a|3
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ~pH!.|k-&
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. o1\N)%
4、说明:子查询(表名1:a 表名2:b) xX<T5Ls
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) bZUw^{~)D
5、说明:显示文章、提交人和最后回复时间 /+B6oE>8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b id+EBVHAd
6、说明:外连接查询(表名1:a 表名2:b) #ZP F&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 -]}#Z:&
7、说明:在线视图查询(表名1:a ) nF]E":
select * from (SELECT a,b,c FROM a) T where t.a > 1; I+W,%)vb
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 "x]7et,
select * from table1 where time between time1 and time2 ]qZj@0#7n
select a,b,c, from table1 where a not between 数值1 and 数值2 *qL'WrB1
9、说明:in 的使用方法 R-W.$-rF
select * from table1 where a [not] in ('值1','值2','值4','值6') _d7;Z%
10、说明:两张关联表,删除主表中已经在副表中没有的信息 F@ |(
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) JgHYuLB
11、说明:四表联查问题: L~h:>I+pG
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... _7u&.l<;
12、说明:日程安排提前五分钟提醒 ?HOnDw.v1
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;B2kot7
13、说明:一条sql 语句搞定数据库分页 H/ e jO_{
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 CUc ,
14、说明:前10条记录 I4ZbMnO
select top 10 * form table1 where 范围 N0$
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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.) uk WL3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) p]~PyzG!
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 k[ pk R{e
(select a from tableA ) except (select a from tableB) except (select a from tableC) i&m6;>?`
17、说明:随机取出10条数据 3qu?qD
select top 10 * from tablename order by newid() Je"XIhBr
18、说明:随机选择记录 sm[zE/2b
select newid() gyy}-^`F
19、说明:删除重复记录 6
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) `B8`<3k/(
20、说明:列出数据库里所有的表名 ./DlHS;
select name from sysobjects where type='U' dpge:Qhr
21、说明:列出表里的所有的 ;*nzb!u\\
select name from syscolumns where id=object_id('TableName') hWn-[w/l_
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。 yO\bVu5V
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 p}I\H
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显示结果: xrNe:Aj
type vender pcs wr:-n
电脑 A 1 e8_EB/)_Z
电脑 A 1 HpeU'0u0VK
光盘 B 2 C[ KMaB
光盘 A 2 wwR}h I(
手机 B 3 >x~Qa@s;
手机 C 3 r>KmrU4Q
23、说明:初始化表table1 F$|d#ny
TRUNCATE TABLE table1 Gf~^Xv!T
24、说明:选择从10到15的记录 /UR;,ts
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc p?
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三、技巧 v$;URF%^
1、1=1,1=2的使用,在SQL语句组合时用的较多 Sy*p6DP
"where 1=1" 是表示选择全部 "where 1=2"全部不选, wYS r.T8Q
如: >G [:Q
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if @strWhere !='' 0x&L'&SpN
begin X}QcXc.d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere lF7".
end Sq2 8=1%
else bVZAf
begin nI73E
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' .M[t5I'\
end ]_L;AD
我们可以直接写成 CqX*.j{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ]-+l.gVFW
2、收缩数据库 >B$ IrM7J
--重建索引 &I{5f-o*
DBCC REINDEX B1Z;
DBCC INDEXDEFRAG c4Q%MRR
--收缩数据和日志 (\
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DBCC SHRINKDB %82:?fq
DBCC SHRINKFILE 79jnYjk
3、压缩数据库 QPFv]^s(
dbcc shrinkdatabase(dbname) ?ZhBS3L
4、转移数据库给新用户以已存在用户权限 ;<F^&/a|yQ
exec sp_change_users_login 'update_one','newname','oldname' !"F8jA}
go (Dba!zSs
5、检查备份集 KfC{/J\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' M,r8 No
6、修复数据库 g\49[U}[~F
ALTER DATABASE [dvbbs] SET SINGLE_USER +t]Ge
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GO )2jH&}K
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK cI@'Pr4:FJ
GO x.I?)x!C'
ALTER DATABASE [dvbbs] SET MULTI_USER cw_B^f8^
GO 'RQEktm
7、日志清除 .\
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SET NOCOUNT ON w H`GzB"
DECLARE @LogicalFileName sysname, ?|Wxqo
@MaxMinutes INT, Uw)B(;Hy?
@NewSize INT 9`&sZ|"3
USE tablename -- 要操作的数据库名 #! (2@N8
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 <c,iu{:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. {XnBj}C
@NewSize = 1 -- 你想设定的日志文件的大小(M) W:8{}Iu<
-- Setup / initialize L5wFbc"u
DECLARE @OriginalSize int W$z^U)|t
SELECT @OriginalSize = size ;hd%wmE
FROM sysfiles zRR^v&.9K
WHERE name = @LogicalFileName (;N#Gqb6l
SELECT 'Original Size of ' + db_name() + ' LOG is ' + u3jLe=Y'\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + MTbCL53!-
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 9S5C{~P4
FROM sysfiles #zb6 7mg~
WHERE name = @LogicalFileName ?uF3Q)rCk
CREATE TABLE DummyTrans l5enlYH
(DummyColumn char (8000) not null) D3+<16[,
DECLARE @Counter INT, C5X!H_p
@StartTime DATETIME, {Bpu-R&T
@TruncLog VARCHAR(255) 1b2xWzpG
SELECT @StartTime = GETDATE(), E6?0/"
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 4Ub7T=LG
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {J;(K~>?m
EXEC (@TruncLog) w:~vfdJ
-- Wrap the log if necessary. s}4k^NGFJ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired e"Tr0k
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) dZCjg0cx
AND (@OriginalSize * 8 /1024) > @NewSize 8(!?y[
BEGIN -- Outer loop. ?nM]eUAP
SELECT @Counter = 0 QC1\Sn /
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) :;&3"-
BEGIN -- update tR?)C=4,
INSERT DummyTrans VALUES ('Fill Log') K[q-[q#yc
DELETE DummyTrans #V@vz#bo=
SELECT @Counter = @Counter + 1 1E$^ul-v
END Et&PzDvU
EXEC (@TruncLog) U@LIw6B!KL
END Z..s /K{
SELECT 'Final Size of ' + db_name() + ' LOG is ' + q9nQ/]rkHF
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ERfSJ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' G~f|Sx
FROM sysfiles u)Vn7zh
WHERE name = @LogicalFileName K/!>[d
DROP TABLE DummyTrans C]krJse@
SET NOCOUNT OFF jZ,=tF
8、说明:更改某个表 cM=_i{c
exec sp_changeobjectowner 'tablename','dbo' o4YF,c+>q
9、存储更改全部表 #\6k_toZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g:&PjKA
@OldOwner as NVARCHAR(128), a.XMeB
@NewOwner as NVARCHAR(128) +"VXw2R_e
AS uAV-wc
DECLARE @Name as NVARCHAR(128) D\z`+TyJ
DECLARE @Owner as NVARCHAR(128) yY80E[v
DECLARE @OwnerName as NVARCHAR(128) q)RTy|NJ^
DECLARE curObject CURSOR FOR w2V:g$~,
select 'Name' = name, 4` :Eiik&p
'Owner' = user_name(uid) Rab7Y,AA
from sysobjects bG]?AiWr
where user_name(uid)=@OldOwner U)_x(B3d/
order by name t'HrI-x
OPEN curObject ^:ehG9
FETCH NEXT FROM curObject INTO @Name, @Owner fczH^+mI
WHILE(@@FETCH_STATUS=0) _TVKvRh
BEGIN Yi|Nd ;
if @Owner=@OldOwner PLK;y
begin 9Hs5uBe
set @OwnerName = @OldOwner + '.' + rtrim(@Name) q]gF[&QZ
exec sp_changeobjectowner @OwnerName, @NewOwner o_.`&Q6n
end bqQR";
-- select @name,@NewOwner,@OldOwner BBj>ML\X
FETCH NEXT FROM curObject INTO @Name, @Owner
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END v3r<kNW_
close curObject 2Gn26L5
deallocate curObject 1j!{?t?
GO B?;P:!/1
10、SQL SERVER中直接循环写入数据 77%I%<#
declare @i int o AM)<#U>
set @i=1 y2>AbrJ
while @i<30 Gg{M
begin }%S#d&wh$_
insert into test (userid) values(@i) m@g9+7
set @i=@i+1 US]I[Y6V
end P u,JR
小记存储过程中经常用到的本周,本月,本年函数 %kV #UzL
Dateadd(wk,datediff(wk,0,getdate()),-1) MJy(B><
Dateadd(wk,datediff(wk,0,getdate()),6) Vv*](iM
Dateadd(mm,datediff(mm,0,getdate()),0) nRheByYm
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) h&:XO9dY
Dateadd(yy,datediff(yy,0,getdate()),0) 0W]vK$\F*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 0!q@b
上面的SQL代码只是一个时间段 mh,a}bX{
Dateadd(wk,datediff(wk,0,getdate()),-1) 6rN.)dL.#N
Dateadd(wk,datediff(wk,0,getdate()),6) :[ll$5E.
就是表示本周时间段. 4.q^r]m*
下面的SQL的条件部分,就是查询时间段在本周范围内的: __,F_9M
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) N$<R6DU]K
而在存储过程中 `5 MK(K
:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 3NN)ql
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) HD>UTX`&mc