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。 4|f}F
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一、基础 Bm}iU~(Z`
1、说明:创建数据库 @c]Xh:I
CREATE DATABASE database-name */_@a?
2、说明:删除数据库 Q7(eq0na
drop database dbname SQE`
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3、说明:备份sql server TGpSulg7
--- 创建 备份数据的 device
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USE master '\t7jQ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' O]ZC+]}/
--- 开始 备份 q~O>a0f0
BACKUP DATABASE pubs TO testBack 75AslL?t
4、说明:创建新表 w+=Q6]FxJ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [b;Uz|o
根据已有的表创建新表: -l[jEJS}
A:create table tab_new like tab_old (使用旧表创建新表) (}jL_E
B:create table tab_new as select col1,col2... from tab_old definition only <+q$XL0
5、说明:删除新表 U&Ab#m;
drop table tabname _-TOeP8#94
6、说明:增加一个列 HsH<m j
Alter table tabname add column col type HH zEQV Lh
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 5~s{N
7、说明:添加主键: Alter table tabname add primary key(col) s.rT]
说明:删除主键: Alter table tabname drop primary key(col) 7Ud'd<
8、说明:创建索引:create [unique] index idxname on tabname(col....) fnOIv#
删除索引:drop index idxname j)";:v
注:索引是不可更改的,想更改必须删除重新建。 @|=UrKA N
9、说明:创建视图:create view viewname as select statement QptOQ3!
删除视图:drop view viewname W>$BF[x!{
10、说明:几个简单的基本的sql语句 [pR)@$"k'
选择:select * from table1 where 范围 "teyi"U+
插入:insert into table1(field1,field2) values(value1,value2) X+at%L=
删除:delete from table1 where 范围 '=#5(O%pp
更新:update table1 set field1=value1 where 范围 O9e.=l
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! h.^o)T
排序:select * from table1 order by field1,field2 [desc] >[Rz
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总数:select count as totalcount from table1 VDa|U9N
求和:select sum(field1) as sumvalue from table1 T V;BNCg
平均:select avg(field1) as avgvalue from table1 TvM24Orct
最大:select max(field1) as maxvalue from table1 Sn ^Aud
最小:select min(field1) as minvalue from table1 jsZY{s=
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11、说明:几个高级查询运算词 JY@X2'>v/
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A: UNION 运算符 -l JYr/MSL
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。 xFwXW)
B: EXCEPT 运算符 27iy4(4
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;A46
C: INTERSECT 运算符 w[sR7T9*
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。 [Xh\mDU.
注:使用运算词的几个查询结果行必须是一致的。 pYh!]0n
12、说明:使用外连接 $T/#1w P
A、left outer join: = t-fYV
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 PCZ]R
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +6376$dC
B:right outer join: XHQh4W3
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。 ppFYc\&=
C:full outer join: n ,1tD
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。 6(.H3bu
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二、提升 $',3Pv
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^ $wJi9D6
法一:select * into b from a where 1<>1
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法二:select top 0 * into b from a ]#5^&w)'
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 5[<F_"x
insert into b(a, b, c) select d,e,f from b; OpqNEo\
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) N8 M'0i?
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 *%?d\8d
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Cya5*U0=
4、说明:子查询(表名1:a 表名2:b) 3Ta>Ki
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) HEpM4xe$
5、说明:显示文章、提交人和最后回复时间 |z+9km7,
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b A6i
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6、说明:外连接查询(表名1:a 表名2:b) [Auc*@
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5m`[MBt2g
7、说明:在线视图查询(表名1:a ) -5xCQJ[
select * from (SELECT a,b,c FROM a) T where t.a > 1; H/`G
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 1MV@5j
select * from table1 where time between time1 and time2 !;+U_j'Pg
select a,b,c, from table1 where a not between 数值1 and 数值2 `Hd9\;NJ
9、说明:in 的使用方法 ]ViOr8u
select * from table1 where a [not] in ('值1','值2','值4','值6') iD`k"\>9
10、说明:两张关联表,删除主表中已经在副表中没有的信息 HL8(lPgS
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5 H *>
11、说明:四表联查问题: @?d?e+B
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 ..... H|K("AVP:
12、说明:日程安排提前五分钟提醒 [ze/@29
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 w%rg\E
13、说明:一条sql 语句搞定数据库分页 j8c6[ih
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 8T7f[?
14、说明:前10条记录 Gh=<0WaF=
select top 10 * form table1 where 范围 ?} X}#
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.) EZ{/]gCK
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Z8fJ{uOIL
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 Jh^8xI,`C
(select a from tableA ) except (select a from tableB) except (select a from tableC) [-]A^?yBM
17、说明:随机取出10条数据 _25d%Ne0
select top 10 * from tablename order by newid() pI5_Hg
18、说明:随机选择记录 hb<k]-'!
select newid() ArL-rJ{}
19、说明:删除重复记录 [9HYO
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ?~ ?Hdv
20、说明:列出数据库里所有的表名 Ph
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select name from sysobjects where type='U' #Z!#;%S
21、说明:列出表里的所有的 5y}BCY2=/
select name from syscolumns where id=object_id('TableName') KqK9X
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。 W\NG>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 Br&^09S
显示结果: T*R{L
type vender pcs sxk*$jO[]
电脑 A 1 uR^.
电脑 A 1 yYk|YX(7U
光盘 B 2 ;.AV;C"
光盘 A 2 wsI5F&R,
手机 B 3 1I
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手机 C 3 B#:E?a;{
23、说明:初始化表table1 qS|AdkNL
TRUNCATE TABLE table1 E#aZvE
24、说明:选择从10到15的记录 =R2l3-HA=
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc DU`v J2
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三、技巧 ^6#-yDZC@
1、1=1,1=2的使用,在SQL语句组合时用的较多 . wmkj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, jNIUsM8e
如: j6}$+!E
if @strWhere !='' ~M; gM]r;
begin s{B_N/^
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Wxc^_iqA1
end h&P
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else 4a?r` '
begin La]4/=a
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' z
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end q}e]*]dJZ
我们可以直接写成 +xq=<jy
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 9GE]<v,_[
2、收缩数据库 3@'lIV
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--重建索引 ^1Yo-T(R
DBCC REINDEX uD[^K1Ag]^
DBCC INDEXDEFRAG 0H<4+
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--收缩数据和日志 Z7oaQ\fR
DBCC SHRINKDB @f%wd2
DBCC SHRINKFILE )lOji7&e
3、压缩数据库 Wkww&Y
dbcc shrinkdatabase(dbname) Bqp&2zg)@
4、转移数据库给新用户以已存在用户权限 w0X$rl1
exec sp_change_users_login 'update_one','newname','oldname' >R#9\/s
go Stt* 1gT
5、检查备份集 MorW\7-}
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' I X?@~'
6、修复数据库 egbb1+tY
ALTER DATABASE [dvbbs] SET SINGLE_USER OFQ{9
GO \wFhTJY
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK C-r."L
GO K]9tc)
ALTER DATABASE [dvbbs] SET MULTI_USER rCkYfTYI
GO p[b7E`7
7、日志清除 L/5z!
SET NOCOUNT ON %~G0[fG
DECLARE @LogicalFileName sysname, \"t`W:
@MaxMinutes INT, D*qzNT@`LR
@NewSize INT v23TL
USE tablename -- 要操作的数据库名 N:d
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 FJW`$5?
@MaxMinutes = 10, -- Limit on time allowed to wrap log. -h=c=P
@NewSize = 1 -- 你想设定的日志文件的大小(M) ?f9$OLEB
-- Setup / initialize s
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DECLARE @OriginalSize int y6bjJ}
SELECT @OriginalSize = size Ty.drM
FROM sysfiles }\U0[x#q
WHERE name = @LogicalFileName Y5Ft96o))x
SELECT 'Original Size of ' + db_name() + ' LOG is ' + I>\}}!
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + V!\n3i?i
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ??q!jm-m
FROM sysfiles FDl,Ey^r/
WHERE name = @LogicalFileName A7.JFf>
CREATE TABLE DummyTrans rpx0|{m
(DummyColumn char (8000) not null) =[ APMig,n
DECLARE @Counter INT, 'aNahzb
@StartTime DATETIME, K7+^Yv\YQx
@TruncLog VARCHAR(255) |b,zw^!e['
SELECT @StartTime = GETDATE(), Dxz5NW4
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Gi;9 S
DBCC SHRINKFILE (@LogicalFileName, @NewSize) RsR] T]4
EXEC (@TruncLog) 7L1\1E:!
-- Wrap the log if necessary. gW/QFZjY
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {7/ A
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1`nc8qC
AND (@OriginalSize * 8 /1024) > @NewSize xcsFODx~
BEGIN -- Outer loop. OCvml 2
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SELECT @Counter = 0 %+D-y+hn
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 9t.fij
BEGIN -- update Wn2Ny jX
INSERT DummyTrans VALUES ('Fill Log') ]j72P
DELETE DummyTrans LRhP7D+A
SELECT @Counter = @Counter + 1 }rFTh I
END w/hh
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EXEC (@TruncLog) 6vMDm0sv
END Z3Bo@`&?
SELECT 'Final Size of ' + db_name() + ' LOG is ' + (/To?`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + wVlSjk
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' fMgcK$
FROM sysfiles 4V!1/w
WHERE name = @LogicalFileName zsHG=Ee*
DROP TABLE DummyTrans M}R@ K;%
SET NOCOUNT OFF 8+=p8e~An
8、说明:更改某个表 yY-FL`-
exec sp_changeobjectowner 'tablename','dbo' R (t!xf
9、存储更改全部表 ;b{pzIe= F
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch k];L!Fj1
@OldOwner as NVARCHAR(128), e?_c[`sg
@NewOwner as NVARCHAR(128) .ruqRGe/
AS cC7"J\+r*
DECLARE @Name as NVARCHAR(128) #rqyy0k0'h
DECLARE @Owner as NVARCHAR(128) S(@*3]!q
DECLARE @OwnerName as NVARCHAR(128) tU8g(ep,o
DECLARE curObject CURSOR FOR !E4E' I=]N
select 'Name' = name, Nck!z8
'Owner' = user_name(uid) c_R)P,P
from sysobjects 6z1aG9G
where user_name(uid)=@OldOwner #nxER
order by name U`?zC~
OPEN curObject o'9OPoof:.
FETCH NEXT FROM curObject INTO @Name, @Owner m$j
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WHILE(@@FETCH_STATUS=0) eA3`]XP.`b
BEGIN 5d)'`hACe
if @Owner=@OldOwner ;5,`Jpca
begin >OF:"_fh
set @OwnerName = @OldOwner + '.' + rtrim(@Name) wghFGHgw
exec sp_changeobjectowner @OwnerName, @NewOwner NN31?wt
end Dwm@E\^ihm
-- select @name,@NewOwner,@OldOwner WO.}DUfG+
FETCH NEXT FROM curObject INTO @Name, @Owner 'YBLU )v[
END Lf$Q
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close curObject <=B1"'\
deallocate curObject R^mu%dw)(%
GO p~v2XdR
10、SQL SERVER中直接循环写入数据
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declare @i int KZ367&>b7
set @i=1 I{i:B
while @i<30 D5o+0R
begin 9q@z[+X
insert into test (userid) values(@i) X}n&`y{/
set @i=@i+1 V{7lltu
end 5n&)q=jk=
小记存储过程中经常用到的本周,本月,本年函数 ==PQ-Ia
Dateadd(wk,datediff(wk,0,getdate()),-1) UKt/0Ze
Dateadd(wk,datediff(wk,0,getdate()),6) hY4)W
Dateadd(mm,datediff(mm,0,getdate()),0) ]6?c8/M
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) [R@q]S/
Dateadd(yy,datediff(yy,0,getdate()),0) Wwa41z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) e/m'a|%:
上面的SQL代码只是一个时间段 y<I Z|f
Dateadd(wk,datediff(wk,0,getdate()),-1) i'eYmm96Q
Dateadd(wk,datediff(wk,0,getdate()),6) . }-@;:yh
就是表示本周时间段. M]%!n3Fb
下面的SQL的条件部分,就是查询时间段在本周范围内的: PV Q#>_~5
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) b#/V;
而在存储过程中 0+VncL)u
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 1@1+4P0NF[
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) U|y;b+n`