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。 Cr%6c3aQ
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一、基础 NpF}~$2
1、说明:创建数据库 fIcra
CREATE DATABASE database-name zj9aaZ}
2、说明:删除数据库 0P6< 4
drop database dbname OX/}j_8E^(
3、说明:备份sql server OgBZoTT
--- 创建 备份数据的 device 3ZU<u;
USE master Z
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' oFUP`p%[
--- 开始 备份 EL-1o02-
BACKUP DATABASE pubs TO testBack Cn(0ID+3f
4、说明:创建新表 YC0FXN V
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) Z]Iyj
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根据已有的表创建新表: #3act)m
A:create table tab_new like tab_old (使用旧表创建新表) !t92_y3
B:create table tab_new as select col1,col2... from tab_old definition only eA(c{
5、说明:删除新表 Q!dNJQpb
drop table tabname (~FLG I
6、说明:增加一个列 ;qT7BUh(%
Alter table tabname add column col type O%(k$fvM
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。 NP*M#3$[
7、说明:添加主键: Alter table tabname add primary key(col) p%6j2;D
说明:删除主键: Alter table tabname drop primary key(col) 4?{e?5)
8、说明:创建索引:create [unique] index idxname on tabname(col....) _GK3]F0
删除索引:drop index idxname wFJ?u?b0Q
注:索引是不可更改的,想更改必须删除重新建。 L'Fy\K\
9、说明:创建视图:create view viewname as select statement 4aQb+t,
删除视图:drop view viewname [1*3 kt*h
10、说明:几个简单的基本的sql语句 qSWnv`hL
选择:select * from table1 where 范围 ?"[h P=3J
插入:insert into table1(field1,field2) values(value1,value2) xPi/nWl`|
删除:delete from table1 where 范围 s$ 2@ |;
更新:update table1 set field1=value1 where 范围 $xf{m9 8
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! z2QZ;ZjvRS
排序:select * from table1 order by field1,field2 [desc] D,rs)
总数:select count as totalcount from table1 P]G`Y>#$r
求和:select sum(field1) as sumvalue from table1 VfiMR%i}
平均:select avg(field1) as avgvalue from table1 ?Q)z5i'g#
最大:select max(field1) as maxvalue from table1 Ibd
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最小:select min(field1) as minvalue from table1 /8SQmh$+e
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11、说明:几个高级查询运算词 JL4\%
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A: UNION 运算符 -/.Xf<y58
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 })R8VJ&C/
B: EXCEPT 运算符 *kXSl73 k
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ]r{-K63P{!
C: INTERSECT 运算符 w$cic
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。 0omg%1vt<A
注:使用运算词的几个查询结果行必须是一致的。 Dm j^aFB0|
12、说明:使用外连接 ?[K+Ym+
A、left outer join: yuvt<kz
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。 >a;^=5E
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 ,))UQ7N
B:right outer join: QM1-w^
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。 tj ,*-).4%
C:full outer join: 7RmL#f`
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。 28;D>6c
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二、提升 C^S?W=1=w
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) U
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法一:select * into b from a where 1<>1 E/<[G?
法二:select top 0 * into b from a kyQ%qBv ^
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) nu] k<^I5|
insert into b(a, b, c) select d,e,f from b; ~ySmN}3~'
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) L!3AiAnr
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 M#J OX/
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 5#.uA_Fov
4、说明:子查询(表名1:a 表名2:b) @.gT&Hq
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) JbG\Ywi0]
5、说明:显示文章、提交人和最后回复时间 <0T4MR7
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~4[2{M.0>@
6、说明:外连接查询(表名1:a 表名2:b) BJk:h-m [
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c V; 1r
7、说明:在线视图查询(表名1:a ) $EbxV"b+
select * from (SELECT a,b,c FROM a) T where t.a > 1; xDu11W+g
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 /d5_-AB(v
select * from table1 where time between time1 and time2 kwdmw_
select a,b,c, from table1 where a not between 数值1 and 数值2 j?1\E9&4-Q
9、说明:in 的使用方法 ]nN']?{7PW
select * from table1 where a [not] in ('值1','值2','值4','值6') p2PD';"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 L1`^~m|
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) R:B-4
11、说明:四表联查问题: 9Ps:]Kp!vN
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... )_b#c+
12、说明:日程安排提前五分钟提醒 yw5MlZ4P=
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 4hztYOhJ{
13、说明:一条sql 语句搞定数据库分页 epm
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ~)D2U:"^xm
14、说明:前10条记录 C81+nR
select top 10 * form table1 where 范围 ;)[RG\
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) bvn?wK
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) E$/`7p8)
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 3=)/-l
(select a from tableA ) except (select a from tableB) except (select a from tableC) z-uJ+SA
17、说明:随机取出10条数据 zzuDI_,/
select top 10 * from tablename order by newid() JGSeu =)
18、说明:随机选择记录
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select newid() SY["(vP%#
19、说明:删除重复记录 kmM_Af&
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +H_Jr'/
20、说明:列出数据库里所有的表名 6}IOUWLB@
select name from sysobjects where type='U' 8iD_md_[
21、说明:列出表里的所有的 oo3ZYA
select name from syscolumns where id=object_id('TableName') \P!v9LX(
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。 a2UER1Yp"
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 7i~::Z <
显示结果: GY<Y,
type vender pcs *-Y77p7u
电脑 A 1 WDKj)f9cy
电脑 A 1 e}f!zA
光盘 B 2 eg)=^b
光盘 A 2 }_0?S0<#
手机 B 3 9M~EH?>+[
手机 C 3 S
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23、说明:初始化表table1 IoJkM-^H&)
TRUNCATE TABLE table1 :q;vZ6Xd
24、说明:选择从10到15的记录 NaG1j+LN
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ZP*Hx
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三、技巧 >9F,=63A
1、1=1,1=2的使用,在SQL语句组合时用的较多 DyG3|5s1R
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 8;p6~&).C~
如: uwQ{y>SG
if @strWhere !='' !li Q;R&
begin :^3MN
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 5h+g^{BE
end 6*kY7
else y .S0^
begin A2uSH@4
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' XV)ej>A-V
end t3 *2Z u
我们可以直接写成 Hy|$7]1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %S$`cp
2、收缩数据库 ~y_TT5+3
--重建索引 +uKlg#wqc
DBCC REINDEX Mmbb}(<
DBCC INDEXDEFRAG B!!xu
--收缩数据和日志 ;Y
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DBCC SHRINKDB v/8K?$"q
DBCC SHRINKFILE tn6\0_5n
3、压缩数据库 kxhvy,t
dbcc shrinkdatabase(dbname) 0^]E-Zf
4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' %D\TLY
go JE9|;A
5、检查备份集 el.;T*Wn
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' B~lrd#qC
6、修复数据库 j3P)cz-0/L
ALTER DATABASE [dvbbs] SET SINGLE_USER er,R}v
GO h;^h[q1'
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 7w|W\J^7r
GO Bb]pUb
ALTER DATABASE [dvbbs] SET MULTI_USER {]]nQ
GO
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7、日志清除 @?3u|m |Z
SET NOCOUNT ON :"3WCB
DECLARE @LogicalFileName sysname, Bg"b,&/^u
@MaxMinutes INT, *@dRL3c^=
@NewSize INT 4kT| /bp
USE tablename -- 要操作的数据库名 2hw3+o6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 G|'DAj%
@MaxMinutes = 10, -- Limit on time allowed to wrap log. '+Gt+Gq+
@NewSize = 1 -- 你想设定的日志文件的大小(M) Y@TZReb
-- Setup / initialize N3MMxm_u
DECLARE @OriginalSize int O%tlj@?
SELECT @OriginalSize = size jWiB_8-6
FROM sysfiles $9+}$lpPd
WHERE name = @LogicalFileName IcoK22/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {w(6Tc
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + TWQf2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' `;*Wt9
FROM sysfiles x7t<F4
WHERE name = @LogicalFileName ub{<m^|)
CREATE TABLE DummyTrans gr4Hh/V
(DummyColumn char (8000) not null) 4.|]R8Mn
DECLARE @Counter INT, yps7MM-r
@StartTime DATETIME, [O&2!x
@TruncLog VARCHAR(255) pxM^|?Hxc
SELECT @StartTime = GETDATE(), "|]'\4UdzQ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' u#\=g:
DBCC SHRINKFILE (@LogicalFileName, @NewSize) x{Gb4=?l
EXEC (@TruncLog) TRcY!
-- Wrap the log if necessary. C=h$8Q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Dsm_T1X
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) )j4]Y dJ
AND (@OriginalSize * 8 /1024) > @NewSize Ol~sCr
BEGIN -- Outer loop. vE>J@g2#
SELECT @Counter = 0 +Ys<V
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ?c+_}ja,
BEGIN -- update /wKW
INSERT DummyTrans VALUES ('Fill Log') Aw;~b&.U{_
DELETE DummyTrans gZM\RJZ_
SELECT @Counter = @Counter + 1 <o3e0JCq
END i t,i^32|
EXEC (@TruncLog) Jq l#z/z
END =~?2i)-mC
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ?M;2H{KG:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + QSW03/_f
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' gPT-zul
FROM sysfiles 245(ajxHC
WHERE name = @LogicalFileName TCX*$ac"
DROP TABLE DummyTrans &0It"17Ej
SET NOCOUNT OFF 69!J'kM[
8、说明:更改某个表 eq<xO28z
exec sp_changeobjectowner 'tablename','dbo' "k)( ,
9、存储更改全部表 zM|d9TS
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch tU}CRh
@OldOwner as NVARCHAR(128), ;jfjRcU
@NewOwner as NVARCHAR(128) 0X~
AS TixHEhw
DECLARE @Name as NVARCHAR(128) $`i$/FE
DECLARE @Owner as NVARCHAR(128) b~Y$!fc
DECLARE @OwnerName as NVARCHAR(128) fk5!/>X
DECLARE curObject CURSOR FOR R KFz6t
select 'Name' = name, W7WHH \L/O
'Owner' = user_name(uid) oR[,?qu@f
from sysobjects ipQJn_:2
where user_name(uid)=@OldOwner #y&3`N z3
order by name j_L 'Ztu3
OPEN curObject k*J}/HO
FETCH NEXT FROM curObject INTO @Name, @Owner D}SRr,4v
WHILE(@@FETCH_STATUS=0) >e/;
BEGIN Cj _Q9/
if @Owner=@OldOwner N~;=*)_VH
begin ua0`&,a3I
set @OwnerName = @OldOwner + '.' + rtrim(@Name) WQ\' z?P
exec sp_changeobjectowner @OwnerName, @NewOwner <dV|N$WV
end z;zyk
-- select @name,@NewOwner,@OldOwner e=o<yf9>Q
FETCH NEXT FROM curObject INTO @Name, @Owner \wCj$-;Jt
END >5%
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close curObject e-ljwCD
deallocate curObject K,&)\r kzD
GO qmdl:J|?
10、SQL SERVER中直接循环写入数据 g:dw%h
declare @i int "w*VyD
set @i=1 z\pT nteO
while @i<30 NN\% X3ri"
begin lf4-Ci*X
insert into test (userid) values(@i) k_r12Bu
set @i=@i+1 pD9*WKEf*
end yc8iT`
小记存储过程中经常用到的本周,本月,本年函数 SuB;Nb7r`
Dateadd(wk,datediff(wk,0,getdate()),-1) c_~)#F%P
Dateadd(wk,datediff(wk,0,getdate()),6) [uT&sZxmg
Dateadd(mm,datediff(mm,0,getdate()),0) TbXp%O:[W
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Lp5LRw
Dateadd(yy,datediff(yy,0,getdate()),0) -7fsfcGM$
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) :UoZ`O~
上面的SQL代码只是一个时间段 p(8H[L4Y
Dateadd(wk,datediff(wk,0,getdate()),-1) &$lz@Z
Dateadd(wk,datediff(wk,0,getdate()),6) G!RbM.6
就是表示本周时间段. :@y!5[88!
下面的SQL的条件部分,就是查询时间段在本周范围内的: Fx0E4\-
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) M n`gd#
而在存储过程中 &{!FE`ZC_
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) sTP`xaY
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Wrf('