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。 ~wuCa!!A
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一、基础 @-[}pZ/
1、说明:创建数据库 w~v6=^
CREATE DATABASE database-name rZdOU?U
2、说明:删除数据库 })^eaLBR4
drop database dbname xS_;p9{E
3、说明:备份sql server #[9UCX^=
--- 创建 备份数据的 device lfDd%.:q4S
USE master :a/rwZ[r
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' &v .S_Ym
--- 开始 备份 L>IP!.J]?
BACKUP DATABASE pubs TO testBack w;ZT-Fti
4、说明:创建新表 G(wK(P0j
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) BH {z]a
根据已有的表创建新表: I ==)a6^
A:create table tab_new like tab_old (使用旧表创建新表) dlfjx
B:create table tab_new as select col1,col2... from tab_old definition only 5&Yt=)c\
5、说明:删除新表 _f@,)n
drop table tabname 6agG*x
6、说明:增加一个列 {rMf/ RAE
Alter table tabname add column col type 36OQHv;&
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。 B1|nT?}J(
7、说明:添加主键: Alter table tabname add primary key(col) ~_JfI7={Jn
说明:删除主键: Alter table tabname drop primary key(col) PI%l
8、说明:创建索引:create [unique] index idxname on tabname(col....) UAXp;W`
删除索引:drop index idxname *B!Ox}CI.L
注:索引是不可更改的,想更改必须删除重新建。 JR]elRR
9、说明:创建视图:create view viewname as select statement 0=HB!{@
删除视图:drop view viewname &j:prc[W
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 THQ #zQ-
插入:insert into table1(field1,field2) values(value1,value2) 3>VL>;75[
删除:delete from table1 where 范围 GYQ:G=
更新:update table1 set field1=value1 where 范围 |MGT8C&^!
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #1$4<o#M
排序:select * from table1 order by field1,field2 [desc] M5:.\0_
总数:select count as totalcount from table1 3Ed
求和:select sum(field1) as sumvalue from table1 ?P[:,0_
平均:select avg(field1) as avgvalue from table1 q-Z<.GTq
最大:select max(field1) as maxvalue from table1 Sc{&h8KMTb
最小:select min(field1) as minvalue from table1 DDkN3\w
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11、说明:几个高级查询运算词 YQ:$m5ai
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A: UNION 运算符 5lHt~hB\
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。 a({Rb?b
B: EXCEPT 运算符 I-!7 EC2{!
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。 kIS )*_
C: INTERSECT 运算符 s3A(`heoq
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。 9U<WR*H
注:使用运算词的几个查询结果行必须是一致的。 IIY_Q9in
12、说明:使用外连接 Ag0w8F
A、left outer join: yWRIh*>nE
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。 YM;ro5_KF
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 c`3`}&g#
B:right outer join: %52e^,//
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。 geK;r0(f
C:full outer join: .?NfV%vv
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。 7#"NKxb
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二、提升 UUWRC1EtI
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ASi2;Q_{_
法一:select * into b from a where 1<>1 I52nQCXi
法二:select top 0 * into b from a 0);5cbV7i
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;C*2Djb*n
insert into b(a, b, c) select d,e,f from b; ,?m@Ko7Y
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) a7_Q8iMe
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 r>8`gAhx
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Y~*p27@fR
4、说明:子查询(表名1:a 表名2:b) oO[eer_S-
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) qmpT G:+
5、说明:显示文章、提交人和最后回复时间 AoGpM,W]5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _hV34:1F
6、说明:外连接查询(表名1:a 表名2:b) Nt\07*`qCr
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -]KgLgJ
7、说明:在线视图查询(表名1:a ) m$[:J
select * from (SELECT a,b,c FROM a) T where t.a > 1; ?3DFm
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 5u9 lKno
select * from table1 where time between time1 and time2 c(Y~5A{TXO
select a,b,c, from table1 where a not between 数值1 and 数值2 m
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9、说明:in 的使用方法 qh>An;:u
select * from table1 where a [not] in ('值1','值2','值4','值6') _s#J\!F
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @dK_w'W
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) lW-G]V
11、说明:四表联查问题: TVvE0y(9
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<{l&u
12、说明:日程安排提前五分钟提醒 [r7Hcb
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 .6[8$8c
13、说明:一条sql 语句搞定数据库分页 .sit5BX
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 nl2Lqu1
14、说明:前10条记录 +~F>:v?Rh
select top 10 * form table1 where 范围 #"A`:bjG
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ?@x$ h
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) .mrv"k\<
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 1H">Rb30@
(select a from tableA ) except (select a from tableB) except (select a from tableC) > Q=e9L=
17、说明:随机取出10条数据 u=@zYA(
select top 10 * from tablename order by newid() hH>a{7V
18、说明:随机选择记录 #QlxEs#%
select newid() 6E_~8oEl
19、说明:删除重复记录 am5;B`}q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) R7:u 8-dU1
20、说明:列出数据库里所有的表名 ~,s'-
select name from sysobjects where type='U' &0*l:uw
21、说明:列出表里的所有的 )<J #RgE
select name from syscolumns where id=object_id('TableName') p\~ a=
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。 )ty>{t
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 lu>G=uCJ
显示结果: R+0fs$su
type vender pcs W)Y-^i5
电脑 A 1 #('R`~
电脑 A 1 &Pv$nMB$I
光盘 B 2 ^K[xVB(&
光盘 A 2 A-vYy1,'
手机 B 3 a>#$&&oQ0
手机 C 3 aTHf+;
23、说明:初始化表table1 .yTo)t
TRUNCATE TABLE table1 3k6Dbz
24、说明:选择从10到15的记录 L6qK3xa}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc L1lDDS#
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三、技巧 -2laM9Ed
1、1=1,1=2的使用,在SQL语句组合时用的较多 :k_)Bh?+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, #Z]Cq0=
如: )=glN<*?
if @strWhere !='' ?:GrM!kq76
begin {1UU `d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [xfg6
end M4?>x[Pw
else nRq[il0 `i
begin #.]W>hN8\
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' x=K'Jj
end a]V#mF |{
我们可以直接写成 ]EN&EA"<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 5't9/8i
2、收缩数据库 k<fR)o
--重建索引 7]5+%[Dg!
DBCC REINDEX !f!YMpN
DBCC INDEXDEFRAG !:vQg+S
--收缩数据和日志 b+AxTe("
DBCC SHRINKDB
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DBCC SHRINKFILE vcy(!r
3、压缩数据库 .d#Hh&jj
dbcc shrinkdatabase(dbname) 92,@tNQQ}
4、转移数据库给新用户以已存在用户权限 (ux9"r^g;x
exec sp_change_users_login 'update_one','newname','oldname' D ][I#vh
go fe6Op
5、检查备份集 D@{m
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qncZpXw^
6、修复数据库 us8ce+
ALTER DATABASE [dvbbs] SET SINGLE_USER uRuu!{$
GO UK8k`;^KI
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK TFbF^Kd#:d
GO C ]zgVbu
ALTER DATABASE [dvbbs] SET MULTI_USER 7|J&fc5BP
GO i7\>uni
7、日志清除 Sxy3cv53
SET NOCOUNT ON y
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DECLARE @LogicalFileName sysname, CpgaQG^
@MaxMinutes INT, #N=_-
@NewSize INT 2gvS`+<TP
USE tablename -- 要操作的数据库名 Mns=X)/hc
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 )OlYz!#?
@MaxMinutes = 10, -- Limit on time allowed to wrap log. KJ-Q$
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@NewSize = 1 -- 你想设定的日志文件的大小(M) 'r^'wv]
-- Setup / initialize 0icB2Jm:D}
DECLARE @OriginalSize int JO87rG
SELECT @OriginalSize = size ]/R>nT
FROM sysfiles ]YDqmIW
WHERE name = @LogicalFileName "tK3h3/Xv
SELECT 'Original Size of ' + db_name() + ' LOG is ' + )B@&q.2B=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + N0
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z%6egi>
FROM sysfiles 3U?^49bJ
WHERE name = @LogicalFileName %z
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CREATE TABLE DummyTrans "VsS-b^ P
(DummyColumn char (8000) not null) HqOnZ>D
DECLARE @Counter INT, m1 p%,
@StartTime DATETIME, hB:+_[=Kj.
@TruncLog VARCHAR(255) K^I$05idi
SELECT @StartTime = GETDATE(), )gR3S%Ju
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' [h\_yU[P
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 7vH4}S\
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EXEC (@TruncLog) 2NL|_W/
-- Wrap the log if necessary. ;ov}%t>UD
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired DEv,!8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _B ]Bd@<w
AND (@OriginalSize * 8 /1024) > @NewSize 3
}rx(
BEGIN -- Outer loop. #)6
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SELECT @Counter = 0 4x/u$Ixzh=
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `UkjrMO
BEGIN -- update 3bugVJ93
INSERT DummyTrans VALUES ('Fill Log') )4+uM'2%
DELETE DummyTrans ."q8 YaW
SELECT @Counter = @Counter + 1 O_SM! !,
END 6& 9q6IIy
EXEC (@TruncLog) B7'2@+(
END /hyCR___
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Gg7ZSB 7
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + aUBu"P$J
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' OBP iLCq
FROM sysfiles twTRw:.!f
WHERE name = @LogicalFileName 5bWy=Xk
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DROP TABLE DummyTrans {\=NZ\
SET NOCOUNT OFF XoiZ"zE
8、说明:更改某个表 nm,Tng
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exec sp_changeobjectowner 'tablename','dbo' A kqGk5e
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9、存储更改全部表 afcyAzIB&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 1Imb"E
@OldOwner as NVARCHAR(128), 0*u X2*
@NewOwner as NVARCHAR(128) <DdzDbgax
AS Od]wh
DECLARE @Name as NVARCHAR(128) c$3ZEe
DECLARE @Owner as NVARCHAR(128) Y9(BxDP_+Y
DECLARE @OwnerName as NVARCHAR(128) ewinG-hX_
DECLARE curObject CURSOR FOR t2%gS"
[
select 'Name' = name, IG@@CH
'Owner' = user_name(uid) (b1rd
from sysobjects =u&NdMy
where user_name(uid)=@OldOwner W!Rr_'yFe)
order by name 7.v{ =UP
OPEN curObject ~H gN'#Y?
FETCH NEXT FROM curObject INTO @Name, @Owner `VOLw*Ci
WHILE(@@FETCH_STATUS=0) ]JHY(H2|
BEGIN "6
if @Owner=@OldOwner dU"C=c(w\
begin _k
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) z;i4F.p
exec sp_changeobjectowner @OwnerName, @NewOwner x\(yjNZH
end n~&e>_;(.
-- select @name,@NewOwner,@OldOwner \cq.M/p
FETCH NEXT FROM curObject INTO @Name, @Owner IRDD
END Z@:R'u2Lk
close curObject [6Nzz]yy
deallocate curObject 3nkO+qQ
GO 'P)[=+O?t
10、SQL SERVER中直接循环写入数据 CQ%yki
declare @i int >qIZ
set @i=1 KTu&R6|
while @i<30 a<V* )
begin V -9z{
insert into test (userid) values(@i) qS2]|7q?Tc
set @i=@i+1 X`n*M]
end X7"hTD
小记存储过程中经常用到的本周,本月,本年函数 |a[ :L
Dateadd(wk,datediff(wk,0,getdate()),-1) e?b<-rL
Dateadd(wk,datediff(wk,0,getdate()),6) 6I\mhw!pQ
Dateadd(mm,datediff(mm,0,getdate()),0) |=}v^o ZC
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) <b;Oap3
Dateadd(yy,datediff(yy,0,getdate()),0) _^0)T@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) s=|&NlO$
上面的SQL代码只是一个时间段 T]J#>LBd
Dateadd(wk,datediff(wk,0,getdate()),-1) zzBq b\Ky
Dateadd(wk,datediff(wk,0,getdate()),6) JYWc3o6
就是表示本周时间段. ^-7{{/
下面的SQL的条件部分,就是查询时间段在本周范围内的: +^.Q%b0Xx
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) h!>NS ?X7
而在存储过程中 z'}?mE3i
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) kOuQR$9s
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) V.274e