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。 xwr8`?]y
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一、基础 q@qsp&0/
1、说明:创建数据库 "#] $r
CREATE DATABASE database-name e!Hh s/&!T
2、说明:删除数据库 _^;Z~/.
drop database dbname i$@:@&(~Y
3、说明:备份sql server `g,..Ns-r
--- 创建 备份数据的 device NgwbQ7)
USE master s>en
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' H. c7Nle
--- 开始 备份 /B3i C#?
BACKUP DATABASE pubs TO testBack G"6 !{4g
4、说明:创建新表 O}P`P'Y|'
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) *fdTpXa
根据已有的表创建新表: ~BF&rx5Q
A:create table tab_new like tab_old (使用旧表创建新表) Rv=YFo[B
B:create table tab_new as select col1,col2... from tab_old definition only ;,TFr}p`
5、说明:删除新表 \8
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drop table tabname >V937
6、说明:增加一个列 yuVs
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Alter table tabname add column col type GmG5[?)
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。 AdmC&!nH
7、说明:添加主键: Alter table tabname add primary key(col) :+Z%; Dc
说明:删除主键: Alter table tabname drop primary key(col) 6mE\OS-I
8、说明:创建索引:create [unique] index idxname on tabname(col....) >Q/Dk7 #
删除索引:drop index idxname iwq!w6+
注:索引是不可更改的,想更改必须删除重新建。 F:VIzyMq<
9、说明:创建视图:create view viewname as select statement XuTD\g3)
删除视图:drop view viewname N;d] 14|
10、说明:几个简单的基本的sql语句 !<oe=)Iz|
选择:select * from table1 where 范围 TseGXYH
插入:insert into table1(field1,field2) values(value1,value2) ~@!bsLSMU
删除:delete from table1 where 范围 I|OoRq
更新:update table1 set field1=value1 where 范围 92c HwWZ!
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %C0Dw\A*:
排序:select * from table1 order by field1,field2 [desc] B[}6-2<>?C
总数:select count as totalcount from table1 D@KlOU{<
求和:select sum(field1) as sumvalue from table1 B1gR5p 0
平均:select avg(field1) as avgvalue from table1 =v\.h=~~
最大:select max(field1) as maxvalue from table1 LscGTs,
最小:select min(field1) as minvalue from table1 *R"/ |Ka
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11、说明:几个高级查询运算词 G5!^*jf
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A: UNION 运算符 Lr+$_ t}r
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 D=$)n_F
B: EXCEPT 运算符 #z(]xI)"
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。 6LZCgdS{
C: INTERSECT 运算符 +mPx8P&%
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。 -/4P3SG/
注:使用运算词的几个查询结果行必须是一致的。 Kq!3wb;
12、说明:使用外连接 }b}m3i1
A、left outer join: df=f62
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。 ~~.}ah/_d
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 ta0|^KAA
B:right outer join: Pfh mo $
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。 @ZJS&23E
C:full outer join: YR70BOxK
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。 >_TZ'FT
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二、提升 NlqImM=r,
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) >~f]_puT
法一:select * into b from a where 1<>1 l}h!B_P'
法二:select top 0 * into b from a 2eogY#
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) q)GdD==
insert into b(a, b, c) select d,e,f from b; maZ)cW?
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}y
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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 xo)P?-
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. [UR-I0 s!/
4、说明:子查询(表名1:a 表名2:b) :m;p:l|W
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) hoP]9&<T
5、说明:显示文章、提交人和最后回复时间 /
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b #Y!a6h+
6、说明:外连接查询(表名1:a 表名2:b) 5G#n"}T
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
7、说明:在线视图查询(表名1:a ) F@t3!bj9
select * from (SELECT a,b,c FROM a) T where t.a > 1; <b.D&
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 #Z #-Ht
select * from table1 where time between time1 and time2 X2_=agEP
select a,b,c, from table1 where a not between 数值1 and 数值2 mq l
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9、说明:in 的使用方法 Ef\-VKh
select * from table1 where a [not] in ('值1','值2','值4','值6') hPh-+Hb
10、说明:两张关联表,删除主表中已经在副表中没有的信息 s~>}a
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) x;S @bY
11、说明:四表联查问题: S/ *E,))m
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 ..... [^)g%|W
12、说明:日程安排提前五分钟提醒 OI*H,Z"
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 dr(*T
13、说明:一条sql 语句搞定数据库分页 m 5.Zu.
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 "%_+-C<L4
14、说明:前10条记录 ]'cs.
select top 10 * form table1 where 范围 Xvv6~
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.) -=="<0c
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +vH4MwG$.&
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 J,hCvm
(select a from tableA ) except (select a from tableB) except (select a from tableC) mw!F{pw
17、说明:随机取出10条数据 '91/md5
select top 10 * from tablename order by newid() 29rX%09T]
18、说明:随机选择记录 {ax:RUQxy
select newid() /z!%d%"
19、说明:删除重复记录 oDR%\VY6T
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ^~dWU>
20、说明:列出数据库里所有的表名 ZNoDFf*h
select name from sysobjects where type='U' 'F<TSy|4kI
21、说明:列出表里的所有的 sB</DS
select name from syscolumns where id=object_id('TableName') XSDpRo
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。 '%qr.T
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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 CAJ'zA|o
显示结果: r$1Qf}J3=
type vender pcs yevPHN"M
电脑 A 1 )4OxY[2J
电脑 A 1 *hx
光盘 B 2 +z( Lr=G
光盘 A 2 #R"*c
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手机 B 3 rsQtMtS2
手机 C 3 -"`=1l
23、说明:初始化表table1 3mgD(,(^
TRUNCATE TABLE table1 >%G1"d?j
24、说明:选择从10到15的记录 ^ c<Ve'-
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Wri<h:1
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三、技巧 d~H`CrQE*
1、1=1,1=2的使用,在SQL语句组合时用的较多 :]KAkhFkbb
"where 1=1" 是表示选择全部 "where 1=2"全部不选, L#J1b!D&<6
如: fl(wV.Je|
if @strWhere !='' \Z/@C lCm
begin uph(V
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere *T/']t
end #4PN"o@
else w}KkvP^
begin 6'/ #+,d'
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' _U(
end Nc`L;CP
我们可以直接写成 L_T5nD^D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere
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2、收缩数据库 DI>s-7
--重建索引 e=
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DBCC REINDEX yAt^;
DBCC INDEXDEFRAG oxs#866x
--收缩数据和日志 ?
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DBCC SHRINKDB @5FQX
DBCC SHRINKFILE bw7@5=?;
3、压缩数据库 t# i#(H
dbcc shrinkdatabase(dbname) b;n[mk
4、转移数据库给新用户以已存在用户权限 J zl6eo[;
exec sp_change_users_login 'update_one','newname','oldname' ,F|f. 7;
go ]DcFySyv
5、检查备份集 HtFDlvdy]
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' $Yq9P0Ya
6、修复数据库 zfU{Kd
ALTER DATABASE [dvbbs] SET SINGLE_USER wT@og|M
GO icgfB-1|i
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK b9krOe*j
GO S'" Df5
ALTER DATABASE [dvbbs] SET MULTI_USER 6Oq7#3]
GO UNYqft4
7、日志清除 #e"[^_C@!
SET NOCOUNT ON Da|z"I
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DECLARE @LogicalFileName sysname, mt
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@MaxMinutes INT, }7Uoh(d
@NewSize INT d0D]Q
USE tablename -- 要操作的数据库名 ^!d3=}:0
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 vN:Ng
@MaxMinutes = 10, -- Limit on time allowed to wrap log. >6T8^Nt
@NewSize = 1 -- 你想设定的日志文件的大小(M) s<Ziegmw|g
-- Setup / initialize d=(mw_-?
DECLARE @OriginalSize int LoV<:|GTI
SELECT @OriginalSize = size 3BI1fXT4=j
FROM sysfiles
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WHERE name = @LogicalFileName R_C)
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _f83-':W6
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4 KiY6)
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (=0.in Z
FROM sysfiles ~$'awY
WHERE name = @LogicalFileName ;l+Leex
CREATE TABLE DummyTrans By|4m
(DummyColumn char (8000) not null) .Mbz3;i0
DECLARE @Counter INT, ?< +WG/(d
@StartTime DATETIME, COlqcq'qAu
@TruncLog VARCHAR(255) *@5 @,=d
SELECT @StartTime = GETDATE(), 9;{CIMg&
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' as|<}:V
DBCC SHRINKFILE (@LogicalFileName, @NewSize) qX%_uOw:%
EXEC (@TruncLog) 1zv'.uu.,
-- Wrap the log if necessary. :;}P*T*PU
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired $FV NCFN%
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ]^E?;1$f?
AND (@OriginalSize * 8 /1024) > @NewSize la!~\wpa
BEGIN -- Outer loop. :TbgFQ86~
SELECT @Counter = 0 lxx2H1([
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) RZLq]8pM
BEGIN -- update 3fj4%P"
INSERT DummyTrans VALUES ('Fill Log') vXs"Dst
DELETE DummyTrans tmq OJ
SELECT @Counter = @Counter + 1 ?s01@f#
END [,Gg^*umS
EXEC (@TruncLog) #mdc [.
END o!Zb0/AP)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + K+eM
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + [n@]
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' u`W2+S
FROM sysfiles SUiOJ[5,
WHERE name = @LogicalFileName B\~}3!j
DROP TABLE DummyTrans -@'FW*b
SET NOCOUNT OFF i1UsIT
8、说明:更改某个表 e'~3oqSvR
exec sp_changeobjectowner 'tablename','dbo' Q,g\
9、存储更改全部表 E GU2fA7x
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 3]Ct6
@OldOwner as NVARCHAR(128), (PLUFT
@NewOwner as NVARCHAR(128) m
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AS cuX)8+
DECLARE @Name as NVARCHAR(128) ch]IzdD
DECLARE @Owner as NVARCHAR(128) #a#F,ZT
DECLARE @OwnerName as NVARCHAR(128) }jXfb@`K
DECLARE curObject CURSOR FOR O-wzz
select 'Name' = name, x2xRBkRg=
'Owner' = user_name(uid) sJZiI}Xc
from sysobjects [agMfn
where user_name(uid)=@OldOwner ,tFg4k[
order by name YK_7ip.a[
OPEN curObject )~>YH*g
FETCH NEXT FROM curObject INTO @Name, @Owner L(-4w+
WHILE(@@FETCH_STATUS=0) dtDFoETz
BEGIN /ZX}Nc g
if @Owner=@OldOwner '1[Ft03
begin cAw/I@jG
set @OwnerName = @OldOwner + '.' + rtrim(@Name) =;L|gtH"
exec sp_changeobjectowner @OwnerName, @NewOwner 4W75T2q#
end \z$= K
-- select @name,@NewOwner,@OldOwner j 7B!h|
FETCH NEXT FROM curObject INTO @Name, @Owner )%TmAaj9d
END F ,kZU$
close curObject mH(:?_KrS-
deallocate curObject zLQx%Yg!
GO }MySaL>
10、SQL SERVER中直接循环写入数据 >*bvw~y,
declare @i int ?ub35NLa
set @i=1 P \I|,
while @i<30 Pz7XAcPQ(
begin X$
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insert into test (userid) values(@i) kh<2BOV
set @i=@i+1 ctQ/wrkU
end :jf3HG
小记存储过程中经常用到的本周,本月,本年函数 Wwo0%<2y
Dateadd(wk,datediff(wk,0,getdate()),-1) 8ag!K*\V<
Dateadd(wk,datediff(wk,0,getdate()),6) V`5O{Gg
Dateadd(mm,datediff(mm,0,getdate()),0) kZ~~/?B
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) TeQV?ZQ#}
Dateadd(yy,datediff(yy,0,getdate()),0) %T[]zJ(
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 4H/OBR
上面的SQL代码只是一个时间段 [g,}gyeS(
Dateadd(wk,datediff(wk,0,getdate()),-1) \8tsDG(1 '
Dateadd(wk,datediff(wk,0,getdate()),6) 4-w{BZuS
就是表示本周时间段. 3|7QUld
下面的SQL的条件部分,就是查询时间段在本周范围内的: %<5'=t'|-U
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) |Tw~@kT@
而在存储过程中 AA_%<zK
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 7)m9"InDI
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1C.VnzRnJ