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。 s"',370
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一、基础 ^jha:d
1、说明:创建数据库 9c^skNbS
CREATE DATABASE database-name ,3]?%t0xe
2、说明:删除数据库 noh|/sPMD
drop database dbname .D,?u"fk|
3、说明:备份sql server hK39_A-
--- 创建 备份数据的 device ;eW'}&|LV
USE master =Etwa
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' |5~wwL@LW7
--- 开始 备份 f']sU/c=
BACKUP DATABASE pubs TO testBack <L/M`(:=k
4、说明:创建新表 XK%W^a*x
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }or2 $\>m
根据已有的表创建新表: L+L"$
A:create table tab_new like tab_old (使用旧表创建新表) `Ixs7{&jU
B:create table tab_new as select col1,col2... from tab_old definition only J7ktfyQ0W
5、说明:删除新表 `xX4!^0Hm
drop table tabname L)/6kt=
6、说明:增加一个列 3aO;@GNJ
Alter table tabname add column col type $35,\ZO>
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 |rxKCzjm
7、说明:添加主键: Alter table tabname add primary key(col) 6mBDd>`0
说明:删除主键: Alter table tabname drop primary key(col) VPM|Rj:d
8、说明:创建索引:create [unique] index idxname on tabname(col....) lj EB
删除索引:drop index idxname pymx\Hd,
注:索引是不可更改的,想更改必须删除重新建。 7}d$*C
9、说明:创建视图:create view viewname as select statement E#<7\p>
删除视图:drop view viewname *9dV/TT~f[
10、说明:几个简单的基本的sql语句 f^!11/Wv
选择:select * from table1 where 范围 XhE$&Ff
插入:insert into table1(field1,field2) values(value1,value2) rkfQr9Vc
删除:delete from table1 where 范围 "u<jbD
更新:update table1 set field1=value1 where 范围 P?q
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! H}h~~7E
排序:select * from table1 order by field1,field2 [desc] 0
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总数:select count as totalcount from table1 ~>#LOT `
求和:select sum(field1) as sumvalue from table1 Ql~#((K
平均:select avg(field1) as avgvalue from table1 _\,rX\
最大:select max(field1) as maxvalue from table1 ^91sl5c8yD
最小:select min(field1) as minvalue from table1 5ys#L&q'Z
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11、说明:几个高级查询运算词 X)Dqeb6
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A: UNION 运算符 /&D'V_Q`*
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 v#<\:|XAg
B: EXCEPT 运算符 2q"_^deI5*
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 =MTj4VXh"
C: INTERSECT 运算符 <#xrrRhm}
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 R=\v3m
注:使用运算词的几个查询结果行必须是一致的。 ]`zjRRd
12、说明:使用外连接 b
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A、left outer join: +"YTCzv;t
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 8?e
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |`w$|pm=
B:right outer join: 09R,'QJ|
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。 Lzh9DYU6
C:full outer join: %<aImR]
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。 M[h1>}$Lz
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二、提升 j';n8|Y9
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) $42Au2Jg
法一:select * into b from a where 1<>1 E7rX1YdR
法二:select top 0 * into b from a o-SRSu
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) C!!mOAhJ
insert into b(a, b, c) select d,e,f from b; H9%l?r5
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) *I:mw8t
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 iY0,WT}&n
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 13ipaz
4、说明:子查询(表名1:a 表名2:b) 4dW3'"R"L
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) yDd=&
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5、说明:显示文章、提交人和最后回复时间 4JGE2ArR
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b xJvLuzUD
6、说明:外连接查询(表名1:a 表名2:b) u=vh
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8W-]t1O%!
7、说明:在线视图查询(表名1:a ) }US7Nw
select * from (SELECT a,b,c FROM a) T where t.a > 1; uyL72($
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 &}zRH}s;
select * from table1 where time between time1 and time2 w`M]0'zls
select a,b,c, from table1 where a not between 数值1 and 数值2 OYBotk]{1
9、说明:in 的使用方法 d4ic9u*D
select * from table1 where a [not] in ('值1','值2','值4','值6') (JevHdI*V
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @(i*-u3Tq
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) jZrY=f
11、说明:四表联查问题: ]|,vCKju
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 ..... iH[E=
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12、说明:日程安排提前五分钟提醒 +yth_9
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 De;, =BSp
13、说明:一条sql 语句搞定数据库分页 7k3p'FeS
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 j,}4TDWa
14、说明:前10条记录 0;vtdM[_
select top 10 * form table1 where 范围 )nhfkW=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.) > P(eW7RL
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) :OHSxb>[
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
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(select a from tableA ) except (select a from tableB) except (select a from tableC) BpH|/7
17、说明:随机取出10条数据 e:qo_eSC^-
select top 10 * from tablename order by newid() 0HjJaML
18、说明:随机选择记录 ab{;Z5O
select newid() !{IC[g n
19、说明:删除重复记录 jUYF.K&
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ?4:rP@
20、说明:列出数据库里所有的表名 LxB&7
select name from sysobjects where type='U' l x7Kw%
21、说明:列出表里的所有的 h:f;mn?x
select name from syscolumns where id=object_id('TableName') 3KtAK9PT
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。 1x{XE*%;
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 6!Qknk$
显示结果: H]BAW *}
type vender pcs SAP;9*f1\
电脑 A 1 8AryIgy>@
电脑 A 1 D^nxtuT*
光盘 B 2 >Z}@7$(7!~
光盘 A 2 B-$+UE>%
手机 B 3 XHy?
手机 C 3 Y7-*2"!
23、说明:初始化表table1 `%uK0qw"
TRUNCATE TABLE table1 Im6U_JsNZh
24、说明:选择从10到15的记录 fO#?k<p
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ^ZR8s^X
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三、技巧 jSB'>m]
1、1=1,1=2的使用,在SQL语句组合时用的较多 )qmFK
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, NK~PcdGl
如: +uELTHH=
if @strWhere !='' )'`CC>Q
begin yu=piP
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ":V%(c
end n_J5zQJ
else E.9^&E}PG
begin S4)A6z$
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' B_cgWJ*4
end Y_+
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我们可以直接写成 [$;,Ua-mt
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere };^}2Xo+
2、收缩数据库 T RDxT
--重建索引 l:)S 3
DBCC REINDEX O~atNrHD
DBCC INDEXDEFRAG '=p?
--收缩数据和日志 T~h.=5
DBCC SHRINKDB ?T
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DBCC SHRINKFILE QypZH"Np
3、压缩数据库 [EER4@_
dbcc shrinkdatabase(dbname) oJh"@6u6K
4、转移数据库给新用户以已存在用户权限 wh*:\_!0\
exec sp_change_users_login 'update_one','newname','oldname' .+HcA x{/2
go 12 -EDg/1
5、检查备份集 ]=|P<F
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' {l@WCR
6、修复数据库 n_}aZB3;U
ALTER DATABASE [dvbbs] SET SINGLE_USER %XR<isn
GO ~TM>"eB b
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK -zdmr"CA
GO PV(4$I}
ALTER DATABASE [dvbbs] SET MULTI_USER z-I|h~ii
GO hVkO%]?
7、日志清除 [Teh*CV
SET NOCOUNT ON =gs~\q
DECLARE @LogicalFileName sysname, `|,Bm|~:
@MaxMinutes INT, {pC\\}
@NewSize INT zQ_z7FJCB
USE tablename -- 要操作的数据库名 9*DEv0}a^
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5x2L(l-2
@MaxMinutes = 10, -- Limit on time allowed to wrap log. yuv4*
@NewSize = 1 -- 你想设定的日志文件的大小(M) DL1
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-- Setup / initialize ~U3Seo }
DECLARE @OriginalSize int
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SELECT @OriginalSize = size Cg^:jd
FROM sysfiles ;t!9]1
WHERE name = @LogicalFileName >8(jW
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 'B,KFA<
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {"t5\U6cKM
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \FXp*FbQ
FROM sysfiles ~?d>fR:X
WHERE name = @LogicalFileName ;Yv14{T!
CREATE TABLE DummyTrans hJLT!33:
(DummyColumn char (8000) not null) Qh8C,"a
DECLARE @Counter INT, UBIIo'u
@StartTime DATETIME, 8jNOEM(0Y+
@TruncLog VARCHAR(255) Z0W0uP;J
SELECT @StartTime = GETDATE(), 2LC
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' #QS?s8IrW
DBCC SHRINKFILE (@LogicalFileName, @NewSize) C99&L3bz^(
EXEC (@TruncLog) %{"dP%|w4}
-- Wrap the log if necessary.
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired }jiK3?e
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 6bUl>4
AND (@OriginalSize * 8 /1024) > @NewSize bS%C?8
BEGIN -- Outer loop. tpGCrn2w>
SELECT @Counter = 0 %I0}4$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) &Sa~/!M
BEGIN -- update 7D9]R#-K
INSERT DummyTrans VALUES ('Fill Log') ]Zk}ZG>6
DELETE DummyTrans o[^Q y(2~
SELECT @Counter = @Counter + 1 -yl;3K]l
END }uiPvO+&p
EXEC (@TruncLog) a
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END mrqaM2,(I
SELECT 'Final Size of ' + db_name() + ' LOG is ' + g>T
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ai9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' s[T{c.F
FROM sysfiles 87}(AO)
WHERE name = @LogicalFileName (l_:XG)7~b
DROP TABLE DummyTrans x,uBJ
SET NOCOUNT OFF U6c@Et ,
8、说明:更改某个表 .
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exec sp_changeobjectowner 'tablename','dbo' ,cD1{T\
9、存储更改全部表 L;lk.~V4T
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 32^#RlSu8
@OldOwner as NVARCHAR(128), @,e8t BL
@NewOwner as NVARCHAR(128) #9,=Owup
AS - wWRm
DECLARE @Name as NVARCHAR(128) ~bGC/I;W>
DECLARE @Owner as NVARCHAR(128) %6HX*_Mr&
DECLARE @OwnerName as NVARCHAR(128) ?;RD u[eD
DECLARE curObject CURSOR FOR ^RDU
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select 'Name' = name, _D
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'Owner' = user_name(uid) zR/IqW.`9
from sysobjects R\y'_S=#a
where user_name(uid)=@OldOwner O5OXw]
order by name }hq^+fC?
OPEN curObject Y/D-V
FETCH NEXT FROM curObject INTO @Name, @Owner dN0mYlu1|
WHILE(@@FETCH_STATUS=0) LD_M 3
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BEGIN {2EMz|&8
if @Owner=@OldOwner o3\,gzJ
begin 9rS,?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) z<h|#@\
exec sp_changeobjectowner @OwnerName, @NewOwner /GN4I!LA
end LuL$v+`
-- select @name,@NewOwner,@OldOwner ~#4~_d.=L
FETCH NEXT FROM curObject INTO @Name, @Owner Gk 6fO
END Y;g% e3nu
close curObject v#F-<?Vv
deallocate curObject 3a^)u-9,x
GO mw"}8y
10、SQL SERVER中直接循环写入数据 +4HlRGH
declare @i int 5us^B8Q
set @i=1 Kr]W
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while @i<30 x{?sn
begin 5{>>,pP&
insert into test (userid) values(@i) fp tIc#4
set @i=@i+1 @(){/cF
end KC]tY9 FK
小记存储过程中经常用到的本周,本月,本年函数 H0+:XF\M
Dateadd(wk,datediff(wk,0,getdate()),-1) q0g1EJar
Dateadd(wk,datediff(wk,0,getdate()),6) eo ?Oir)
Dateadd(mm,datediff(mm,0,getdate()),0) B.RRdK+:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) XR+rT
Dateadd(yy,datediff(yy,0,getdate()),0) "/!'9na{QL
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 6%UY1Q.?
上面的SQL代码只是一个时间段 r@Nl2
Dateadd(wk,datediff(wk,0,getdate()),-1) 3(o7co-f
Dateadd(wk,datediff(wk,0,getdate()),6) )$h-ZYc
就是表示本周时间段. 82s5VQ6
下面的SQL的条件部分,就是查询时间段在本周范围内的: {(!)P
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) AA2ui%
而在存储过程中 q}sK
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }_]As}E
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) w?S8@|MK