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。 kMy<G8 s
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一、基础 IX9K.f
1、说明:创建数据库 0[/vQ+O ]2
CREATE DATABASE database-name -kl;!:'.3
2、说明:删除数据库 14H'!$
drop database dbname nbGoJC:U
3、说明:备份sql server 6xHi\L
--- 创建 备份数据的 device :zlpfm2
USE master Ah-8"`E
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' xf/m!b"p
--- 开始 备份 Fn!SGX~kx$
BACKUP DATABASE pubs TO testBack ibJl;sJ
4、说明:创建新表 7JI:=yY!>:
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) !z MDP/V
根据已有的表创建新表: b^ sb]bZW
A:create table tab_new like tab_old (使用旧表创建新表) zmI5"K"'F
B:create table tab_new as select col1,col2... from tab_old definition only XA1f' Kk
5、说明:删除新表 JA`H@qE
drop table tabname f&ytK
6、说明:增加一个列 FI{AZb_'
Alter table tabname add column col type HT"gT2U+
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。 xW>ySEf
7、说明:添加主键: Alter table tabname add primary key(col) lkA^\+Ct
说明:删除主键: Alter table tabname drop primary key(col) "cMNdR1^,y
8、说明:创建索引:create [unique] index idxname on tabname(col....) xuUx4,Z
删除索引:drop index idxname S[mM4et|
注:索引是不可更改的,想更改必须删除重新建。 vZ@g@zB4o0
9、说明:创建视图:create view viewname as select statement |3;(~a)%
删除视图:drop view viewname p<KIF>rf|
10、说明:几个简单的基本的sql语句 =_
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选择:select * from table1 where 范围 %c X"#+e
插入:insert into table1(field1,field2) values(value1,value2) >,"sHm}l%
删除:delete from table1 where 范围 ,=|4:F9
更新:update table1 set field1=value1 where 范围 `
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! rjUBLY1(
排序:select * from table1 order by field1,field2 [desc] V^n0GJNo
总数:select count as totalcount from table1 JrDHRIkgm
求和:select sum(field1) as sumvalue from table1 B3mS]
平均:select avg(field1) as avgvalue from table1 \D?:J3H*]
最大:select max(field1) as maxvalue from table1 ~*}$>@f{[X
最小:select min(field1) as minvalue from table1 WPo:^BD
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11、说明:几个高级查询运算词 -U-P}6^
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A: UNION 运算符 \}JrFc%O
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 #Qh>z%Mn^3
B: EXCEPT 运算符 dl0FQNz8@B
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 0xCz'mJ
C: INTERSECT 运算符 q8xd*--#
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 hj!+HHYSk
注:使用运算词的几个查询结果行必须是一致的。 b5pMq$UVL
12、说明:使用外连接 *Qkc[XHqy
A、left outer join: =eBmBn
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。 z/ 7$NxJH
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 3;_
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B:right outer join: -(#-I$z
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。 |~K(F<;j
C:full outer join: oM,- VUr
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。 CPviR<ms_
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二、提升 \Q&,ISO\
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) nY_?Jq
法一:select * into b from a where 1<>1 ^Ga&}-
法二:select top 0 * into b from a =X1?_~}
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jL>:>r
insert into b(a, b, c) select d,e,f from b; 1 ] #9
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) K
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 3yV'XxC
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. j~`\XX{>
4、说明:子查询(表名1:a 表名2:b) {]kaJ{U>
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) \+nGOvM
5、说明:显示文章、提交人和最后回复时间 3`F) AWzdr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b =Z,5$6%)
6、说明:外连接查询(表名1:a 表名2:b) =X(%Svnp
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H&4~Uo.5
7、说明:在线视图查询(表名1:a ) Rc[ 0aj:
select * from (SELECT a,b,c FROM a) T where t.a > 1; zY=jXa)K~
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 A\QJLWBv^$
select * from table1 where time between time1 and time2 7:Ztuc]
select a,b,c, from table1 where a not between 数值1 and 数值2 ?=Db@97
9、说明:in 的使用方法 o3N] `xD'
select * from table1 where a [not] in ('值1','值2','值4','值6') \we\0@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 ?&X6:KJQ
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 0CAa^Q^w
11、说明:四表联查问题: SVWIEH0?
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 ..... $t/rOo9cV
12、说明:日程安排提前五分钟提醒 bRo|uJ:d
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 d]wD[]
13、说明:一条sql 语句搞定数据库分页 86qI
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 u\1>gDI )|
14、说明:前10条记录 sL^yB
select top 10 * form table1 where 范围 <
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) +K~NV?c
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ^,8R,S\}$
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 b]Z@^<_E
(select a from tableA ) except (select a from tableB) except (select a from tableC) aFj.i8+
17、说明:随机取出10条数据 4n0xE[-
select top 10 * from tablename order by newid() /)>S<X
18、说明:随机选择记录 cYNV\b4-
select newid() u0o'K9.r
19、说明:删除重复记录 NwlU%{7W6
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) o[\HOe~;
20、说明:列出数据库里所有的表名 p9qKLJ*.C
select name from sysobjects where type='U' $m| V :/
21、说明:列出表里的所有的 d8o53a]
select name from syscolumns where id=object_id('TableName') -db75=
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 \3XqHf3|o
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ^%>kO,
显示结果: mD58T2Z
type vender pcs jd-glE,Y/
电脑 A 1 K^[#]+nQ
电脑 A 1 LnsD
光盘 B 2 Ao9R:|9
光盘 A 2 DcD{*t?x
手机 B 3 %O[N}_XHEh
手机 C 3 JXqr3Np1
23、说明:初始化表table1 l$xxrb9P!
TRUNCATE TABLE table1 GqKsK
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24、说明:选择从10到15的记录 zaimGMJ ,
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc TQ@d~GR
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三、技巧 3gZ8.8q3
1、1=1,1=2的使用,在SQL语句组合时用的较多 3_$w|ET
"where 1=1" 是表示选择全部 "where 1=2"全部不选, jXg
如: An`3Ex[
if @strWhere !='' IE2"rQ T
begin .)tSg
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere XMIbUbUk-
end f9u^ R=Ff[
else hT g<*
begin `#P$ ]:
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Me5{_n
end :[l\@>H1tX
我们可以直接写成 .Ajzr8P
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere / |r'
2、收缩数据库 u{<"NR h
--重建索引 b*kfWG-6t
DBCC REINDEX A^ \.Z4=d"
DBCC INDEXDEFRAG 4u;9J*r4
--收缩数据和日志 */qtzt
DBCC SHRINKDB 4,Ic}CvM
DBCC SHRINKFILE 13k
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3、压缩数据库 !^oV #
dbcc shrinkdatabase(dbname) kOwMs<1J
4、转移数据库给新用户以已存在用户权限 g=L]S-e
exec sp_change_users_login 'update_one','newname','oldname' 56lCwXCgA
go DOS0;^f
5、检查备份集 0|4%4Mt
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' hwYQGtjF
6、修复数据库 LW6ZAETyL
ALTER DATABASE [dvbbs] SET SINGLE_USER y9H%
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GO <xpph
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ZUm?*.g\^
GO \>. LW9
ALTER DATABASE [dvbbs] SET MULTI_USER M9\#Aq&\i
GO }|OaL*|u
7、日志清除 >SF Uy\3
SET NOCOUNT ON 1$/MrPT(b
DECLARE @LogicalFileName sysname, &F
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@MaxMinutes INT, 82{ Vc
@NewSize INT B(g_Gm<
USE tablename -- 要操作的数据库名 Q#I"_G&{
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 C*=Xk/0
@MaxMinutes = 10, -- Limit on time allowed to wrap log. K7knK
@NewSize = 1 -- 你想设定的日志文件的大小(M) fEf_F
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-- Setup / initialize $``1PJoi
DECLARE @OriginalSize int JCx
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SELECT @OriginalSize = size +j_;(Gw7
FROM sysfiles |y;}zQB-dH
WHERE name = @LogicalFileName )>
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + VZr>U*J[:
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + {Bs~lC$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ia&AW
FROM sysfiles OVzt\V*+%W
WHERE name = @LogicalFileName e~%
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CREATE TABLE DummyTrans Pt:e!qX)
(DummyColumn char (8000) not null) M-L2w"
DECLARE @Counter INT, -H^oXeN
@StartTime DATETIME, mYN7kYR}<`
@TruncLog VARCHAR(255) <#=N
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SELECT @StartTime = GETDATE(), /@ !CKh`
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :o-,SrORM
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Ei}/iBG@
EXEC (@TruncLog) :K`ESq!8u
-- Wrap the log if necessary. RoA?p;]<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired K;?,FlH
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) <~ad:[
AND (@OriginalSize * 8 /1024) > @NewSize 6fH@wQ"wN
BEGIN -- Outer loop. q\Q{sv_
SELECT @Counter = 0 TNCgaTJ{h
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) #4MBoN(3
BEGIN -- update <9E0iz+j
INSERT DummyTrans VALUES ('Fill Log') ptatzp]c#
DELETE DummyTrans 5Wyz=+?m|
SELECT @Counter = @Counter + 1 6vuq1
END [Aj Q#;#Q
EXEC (@TruncLog) jUv!9Y}F
END 4(e59ZgY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + =L%DX#8
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + FMNm,O]
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ~CB[9D=
FROM sysfiles OaJB=J%
WHERE name = @LogicalFileName _It ,%<3
DROP TABLE DummyTrans _\Q^x)w6
SET NOCOUNT OFF fbyQjvURnC
8、说明:更改某个表 KoE8Mp
exec sp_changeobjectowner 'tablename','dbo' T{V/+RM
9、存储更改全部表 Re:jVJgBz
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 6:GTD$Uz.
@OldOwner as NVARCHAR(128), PWh^[Rd)
@NewOwner as NVARCHAR(128) H gTUy[(
AS HX'FYt/?t
DECLARE @Name as NVARCHAR(128) 9I1tN
DECLARE @Owner as NVARCHAR(128) 3czeTj
DECLARE @OwnerName as NVARCHAR(128) [U}+sTQ
DECLARE curObject CURSOR FOR [Vd[-
select 'Name' = name, *D o/+[Ae
'Owner' = user_name(uid) ;Op3?_
from sysobjects +4[^!q*
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where user_name(uid)=@OldOwner s2?T5oWU
order by name b KTcZG
OPEN curObject tQZs.1=z
FETCH NEXT FROM curObject INTO @Name, @Owner &PkLp4mQ
WHILE(@@FETCH_STATUS=0) Y2xL>F
BEGIN @L.82p{h
if @Owner=@OldOwner Um1[sMc{au
begin {o5V7*P;_
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 4&8Gr0C
exec sp_changeobjectowner @OwnerName, @NewOwner jV.g}F+1m
end :[ k4Z]t8
-- select @name,@NewOwner,@OldOwner +k
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FETCH NEXT FROM curObject INTO @Name, @Owner (P&4d~)m
END rl9.]~
close curObject g{W;I_P^9
deallocate curObject x~.:64
GO wi9DhVvc 0
10、SQL SERVER中直接循环写入数据 0ye!R
declare @i int 4}`
set @i=1 .sQ=;w/ZA
while @i<30 R[49(>7H4
begin d,8mY/S>w
insert into test (userid) values(@i) e[sK@jX6
set @i=@i+1 |
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end bSVlk`
小记存储过程中经常用到的本周,本月,本年函数 :2njp%
Dateadd(wk,datediff(wk,0,getdate()),-1) e]jH+IR:>
Dateadd(wk,datediff(wk,0,getdate()),6) Bo<>e~6P
Dateadd(mm,datediff(mm,0,getdate()),0) R!l:O=[<
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) u:aW 8
Dateadd(yy,datediff(yy,0,getdate()),0) !LkWzn3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) YF+n
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上面的SQL代码只是一个时间段 dw.F5?j`b
Dateadd(wk,datediff(wk,0,getdate()),-1) n@ w^V
Dateadd(wk,datediff(wk,0,getdate()),6) sAg Kg=)
就是表示本周时间段. P&Pj>!T5
下面的SQL的条件部分,就是查询时间段在本周范围内的: ]skkoM
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ?"z]A7<Hj
而在存储过程中 mxb06u_
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) n}s~+USZX
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 3Tn)Z1o