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。 Sv[+~co<l
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一、基础 /?S,u,R
1、说明:创建数据库 "gt*k#
CREATE DATABASE database-name c/,B ?
2、说明:删除数据库 `91?^T;\F
drop database dbname ^NrC8,p
3、说明:备份sql server :(i=> ~O
--- 创建 备份数据的 device XZxzw*Y1J
USE master cB2~W%H
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^F-AZP
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--- 开始 备份 <#lNi.?.
BACKUP DATABASE pubs TO testBack 6^TWY[z2%
4、说明:创建新表 6W)#FO`
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) tA-p!#V<k1
根据已有的表创建新表: v#9Uy}NJ9
A:create table tab_new like tab_old (使用旧表创建新表) qO>A6
B:create table tab_new as select col1,col2... from tab_old definition only vcSb:('
5、说明:删除新表 MwWN;_#EO)
drop table tabname =l%|W[OO
6、说明:增加一个列 D/tFN+|P
Alter table tabname add column col type cFoeyI# v
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。 bJL ,pe+u
7、说明:添加主键: Alter table tabname add primary key(col) /%P,y+<}iG
说明:删除主键: Alter table tabname drop primary key(col) \m+;^_;5GW
8、说明:创建索引:create [unique] index idxname on tabname(col....) hD7Lgi-N)W
删除索引:drop index idxname f1I/aR V:+
注:索引是不可更改的,想更改必须删除重新建。 da$ErN'{
9、说明:创建视图:create view viewname as select statement u7
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删除视图:drop view viewname KvlLcE~`o
10、说明:几个简单的基本的sql语句 vH{JLN2
选择:select * from table1 where 范围 V4|l7
插入:insert into table1(field1,field2) values(value1,value2) nc:K!7:
删除:delete from table1 where 范围 #|6M*;l N|
更新:update table1 set field1=value1 where 范围 t8Giv89{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! {Yv5Z.L&(
排序:select * from table1 order by field1,field2 [desc] cN|
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总数:select count as totalcount from table1 =2d h}8Mz
求和:select sum(field1) as sumvalue from table1 }1YQ?:@
平均:select avg(field1) as avgvalue from table1 'l._00yu
最大:select max(field1) as maxvalue from table1 nb(Od,L
最小:select min(field1) as minvalue from table1 y&2O)z!B
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11、说明:几个高级查询运算词 *YWk.
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A: UNION 运算符 7@ mP;K0
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。 rv%^2h<&
B: EXCEPT 运算符 ]dnB,
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)rSgzI
C: INTERSECT 运算符 _8OSDW*D5t
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。 Og"\@n
注:使用运算词的几个查询结果行必须是一致的。 7G23D
12、说明:使用外连接 U_5\FM
A、left outer join: E1>zKENN;
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。 j6BFh=?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 =T|m#*{.L
B:right outer join: vtXZ`[D,l)
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。 YJBf~0r
C:full outer join: mA6Nmq%{ 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。 LS4E.Xdn
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二、提升 "ax"k0
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <*DP G\6Ma
法一:select * into b from a where 1<>1 !{ /AJb
法二:select top 0 * into b from a G4)X~.Fy
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \yY2 mr
insert into b(a, b, c) select d,e,f from b; r'& 6P-Vm
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) P>ZIP*
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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 /@]@Tz@'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. N"2P]Zr
4、说明:子查询(表名1:a 表名2:b) L_}F.nbS5
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) Xldz&&@
5、说明:显示文章、提交人和最后回复时间 TRQH{O\O
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b "$|ne[b2
6、说明:外连接查询(表名1:a 表名2:b) CL"q"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (W_U<~`t
7、说明:在线视图查询(表名1:a ) &(rR)cG
select * from (SELECT a,b,c FROM a) T where t.a > 1; Z_[jah
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 TXK82qTdf
select * from table1 where time between time1 and time2 R5MY\^H/A
select a,b,c, from table1 where a not between 数值1 and 数值2 {&.?u1C.\
9、说明:in 的使用方法 A{ a`%FAV
select * from table1 where a [not] in ('值1','值2','值4','值6') ]nQ(|$rW
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ^I6GH?19>e
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) A@JZK+WB}
11、说明:四表联查问题: Iih]q
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 ..... >y
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12、说明:日程安排提前五分钟提醒 kB;!EuL
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5
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13、说明:一条sql 语句搞定数据库分页 X1Y+ao 1)
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 $Z4IPs
14、说明:前10条记录 W&Kjh|[1QZ
select top 10 * form table1 where 范围 d]QCk&XU
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) w"BMJ+
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 3(>NS ?lX
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 \k*h& :$
(select a from tableA ) except (select a from tableB) except (select a from tableC) lcEin*Oc
17、说明:随机取出10条数据 Y,s@FGI2
select top 10 * from tablename order by newid() O_y?5 3X
18、说明:随机选择记录 f`8mES'gc8
select newid() "SN+ ^`
19、说明:删除重复记录 5tl uS
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) HDT-f9%}<4
20、说明:列出数据库里所有的表名 kS$m$
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select name from sysobjects where type='U' a1#
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21、说明:列出表里的所有的 ;U$EM+9
select name from syscolumns where id=object_id('TableName') Ems0"e
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 2~2j?\AEd.
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type y,=TB[d#
显示结果: *p7_rY
type vender pcs O,?aVgY
电脑 A 1 -WK
电脑 A 1 JM Ikr9/$
光盘 B 2 S*?x|&a
光盘 A 2 +
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手机 B 3 /a:L"7z
手机 C 3 XpibI3:<
23、说明:初始化表table1 xzTF| Z\
TRUNCATE TABLE table1 qn|~z@"
24、说明:选择从10到15的记录 .?p\=C@C+
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc rty&\u@}
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三、技巧 #[ch?K
1、1=1,1=2的使用,在SQL语句组合时用的较多 7.tEi}O&_g
"where 1=1" 是表示选择全部 "where 1=2"全部不选, HVK./yqy
如: :_"%o=
if @strWhere !='' |!H@{o
begin }?XNA.Wz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere keL!;q|r-)
end ?tFsSU
else .q9wyVi7GI
begin UIi`bbJ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' >PMLjXK
end *IBCThj
我们可以直接写成 u3@v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere
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2、收缩数据库 _f@,
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--重建索引 6b9&V`
DBCC REINDEX :T# "bY
DBCC INDEXDEFRAG ;#Pc^Yzc1
--收缩数据和日志 $yg=tWk
DBCC SHRINKDB &u7oa
DBCC SHRINKFILE om}jQJ]KH
3、压缩数据库 N(BCe\FV
dbcc shrinkdatabase(dbname) `<^1Ik[g
4、转移数据库给新用户以已存在用户权限 Qv>rww]
exec sp_change_users_login 'update_one','newname','oldname' IYk^eG:;
go K5SP8<.
5、检查备份集 ;IX*4E'4s
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Z* L{;
6、修复数据库 H{nYZOf/
ALTER DATABASE [dvbbs] SET SINGLE_USER UAq%Y8KA
GO }g|)+V\A
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK J}J7A5P
GO 58H%#3Fy
ALTER DATABASE [dvbbs] SET MULTI_USER u }~%9Pi
GO +qzCy/_gd
7、日志清除 Yl$Cj>FG
SET NOCOUNT ON Du."O]syD
DECLARE @LogicalFileName sysname, !wZ9P
@MaxMinutes INT, V_-{TGKX
@NewSize INT $(U}#[Vie
USE tablename -- 要操作的数据库名 7f\@3r
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 A T'P=)F@
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zm('\KvT
@NewSize = 1 -- 你想设定的日志文件的大小(M) K?:wX(JYT
-- Setup / initialize F_&bE@k
DECLARE @OriginalSize int 0[T>UEI?
SELECT @OriginalSize = size v5N2$Sqp*
FROM sysfiles jwd{CN%
WHERE name = @LogicalFileName &9F(uk=X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + T^~9'KDd
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :[ AP^
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' V9Gk``F<RZ
FROM sysfiles T11;LSD
WHERE name = @LogicalFileName K0Zq)<
CREATE TABLE DummyTrans ;&%G)f
(DummyColumn char (8000) not null) r(::3TF%#q
DECLARE @Counter INT, --9Z
@StartTime DATETIME, I{0bsTp;
@TruncLog VARCHAR(255) 9x40
SELECT @StartTime = GETDATE(), c@1q8,
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @ dF]X
DBCC SHRINKFILE (@LogicalFileName, @NewSize) g2'Q)w
EXEC (@TruncLog) t[-0/-4
-- Wrap the log if necessary. HAr_z@#E
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired }.R].4gT
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (&a<6k
AND (@OriginalSize * 8 /1024) > @NewSize WgK |r~
BEGIN -- Outer loop. QP?Deltp
SELECT @Counter = 0 w(xRL#%
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 5Si\hk:o
BEGIN -- update 'o*:~n
INSERT DummyTrans VALUES ('Fill Log') ,$qqHSd1M
DELETE DummyTrans qm&Z_6Pw
SELECT @Counter = @Counter + 1 4/Bn9F
END %g<J"/
EXEC (@TruncLog) }_{QsPx9
END Y[yw8a
SELECT 'Final Size of ' + db_name() + ' LOG is ' + /-W-MP=Wd
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + > \KVg(?D
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' FTg4i\Wp
FROM sysfiles ,LHQ@/}A C
WHERE name = @LogicalFileName r
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DROP TABLE DummyTrans K{s%h0
SET NOCOUNT OFF 2i@t;h2E
8、说明:更改某个表 S"z cSkF
exec sp_changeobjectowner 'tablename','dbo' ]$vJK
9、存储更改全部表 N3`W%ws`~
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch X0.-q%5
@OldOwner as NVARCHAR(128), P6E=*^^m(
@NewOwner as NVARCHAR(128) +L$,jZqS
AS Kx;DmwX-
DECLARE @Name as NVARCHAR(128) Twj?SV
DECLARE @Owner as NVARCHAR(128) M5Twulz/w
DECLARE @OwnerName as NVARCHAR(128) 'C9H6)Zq)
DECLARE curObject CURSOR FOR oYG].PC
select 'Name' = name, gAY%VFBP0
'Owner' = user_name(uid) dTV:/QM
from sysobjects O(( kv|X4
where user_name(uid)=@OldOwner `=0J:
order by name ~',}]_'oR-
OPEN curObject I'[hvp
FETCH NEXT FROM curObject INTO @Name, @Owner z]YP
WHILE(@@FETCH_STATUS=0) zTa>MzH1-;
BEGIN `>q|_w\e
if @Owner=@OldOwner B~u_zZE
begin DJ9;{,gm
set @OwnerName = @OldOwner + '.' + rtrim(@Name) N+vU@)_lC
exec sp_changeobjectowner @OwnerName, @NewOwner 0KF)+`CC>
end ,ZYj8^gF
-- select @name,@NewOwner,@OldOwner #89h}mp'
FETCH NEXT FROM curObject INTO @Name, @Owner Bn"r;pqWiT
END $nOd4{s_
close curObject F)0I7+lP
deallocate curObject a#0GmK
GO /Jc?;@{
10、SQL SERVER中直接循环写入数据 |m%M$^sZ}
declare @i int QS~;C&1Hl
set @i=1 ')9%eBaeK
while @i<30 @x@w<e%
begin PSdH9ea
insert into test (userid) values(@i) r]{fjw(~
set @i=@i+1 p.2>-L
end O^]I>A#d
小记存储过程中经常用到的本周,本月,本年函数 8dw]i1t<
Dateadd(wk,datediff(wk,0,getdate()),-1) :8_`T$8i4
Dateadd(wk,datediff(wk,0,getdate()),6) {tE/Jv $
Dateadd(mm,datediff(mm,0,getdate()),0) %(-YOTDr
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) -%=StWdb
Dateadd(yy,datediff(yy,0,getdate()),0) ^/W7Xd(s
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) tH:K6^oR
上面的SQL代码只是一个时间段 }eX_p6bBw
Dateadd(wk,datediff(wk,0,getdate()),-1) X*~NE\
Dateadd(wk,datediff(wk,0,getdate()),6) @Y>3 -,o,S
就是表示本周时间段. +fhyw{
下面的SQL的条件部分,就是查询时间段在本周范围内的: |7Q8WjCQ{m
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) R0<ka[+
而在存储过程中 n;"4`6L~
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) z#!xqIg0
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 4:}`X