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。 LY+|[qka
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一、基础 *-xU2
1、说明:创建数据库 fw[y+Bi&
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CREATE DATABASE database-name N]RZbzK_5G
2、说明:删除数据库 =Fdg/X1
drop database dbname ]5%/3P,/
3、说明:备份sql server ~H!S,"n^,P
--- 创建 备份数据的 device "+unS)M;Y
USE master N<DGw?Rl
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \(%Y%?dy
--- 开始 备份 '? jlH0;
BACKUP DATABASE pubs TO testBack jMpD+Mb
4、说明:创建新表 |.wEm;Bz
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) H'HSD,>(
根据已有的表创建新表:
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A:create table tab_new like tab_old (使用旧表创建新表) ]n-:Yv5 W
B:create table tab_new as select col1,col2... from tab_old definition only 9Vf1Xz
5、说明:删除新表 o: ;"w"G
drop table tabname 0
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6、说明:增加一个列 zz& ?{vJ
Alter table tabname add column col type cYqfsd# B
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。 ,*7d
7、说明:添加主键: Alter table tabname add primary key(col) -ig6w.%lk
说明:删除主键: Alter table tabname drop primary key(col) wd)jl%
8、说明:创建索引:create [unique] index idxname on tabname(col....) D1&A,2wO
删除索引:drop index idxname <\;#jF%V
注:索引是不可更改的,想更改必须删除重新建。 o;?/HE%,[
9、说明:创建视图:create view viewname as select statement &d|r~NhP
删除视图:drop view viewname (64yg
10、说明:几个简单的基本的sql语句 !fj(tPq
选择:select * from table1 where 范围 ZI=v.wa
插入:insert into table1(field1,field2) values(value1,value2) "U7qo}`I
删除:delete from table1 where 范围 5YrBW:_OI
更新:update table1 set field1=value1 where 范围 M}!2H*
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! &~W:xg(jN
排序:select * from table1 order by field1,field2 [desc] 3d|9t9v
总数:select count as totalcount from table1 YQY%M>F@d%
求和:select sum(field1) as sumvalue from table1 3$X'Y]5a
平均:select avg(field1) as avgvalue from table1 HbW0wuI
最大:select max(field1) as maxvalue from table1 '}$Dgp6e
最小:select min(field1) as minvalue from table1 N$[{8yil^w
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11、说明:几个高级查询运算词 k-}b{
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A: UNION 运算符 {D=@n4JO
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 f;b[w
B: EXCEPT 运算符 ,N0#!<}4
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 /i77
C: INTERSECT 运算符 #f+$Ddg*
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。 =kuMWaD
注:使用运算词的几个查询结果行必须是一致的。 /E\%>wv
12、说明:使用外连接 [KxF'm z9
A、left outer join: C9t4#"
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。 7a~X:#
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 SCz318n
B:right outer join: %Z1N;g0
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。 s~Te
C:full outer join: bcYF\@};
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。 6H7],aMg$A
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二、提升 @mfEKU!
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ^f(@gS}?
法一:select * into b from a where 1<>1 V 0rZz
法二:select top 0 * into b from a }I>tO9M
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) GP#aya
insert into b(a, b, c) select d,e,f from b; 8e(\%bX
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) L+q/){Dd(
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 >:b Q
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @/31IOIV]`
4、说明:子查询(表名1:a 表名2:b) ^-
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) -(=eM3o-9m
5、说明:显示文章、提交人和最后回复时间 }B1!gz$YNO
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b g
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6、说明:外连接查询(表名1:a 表名2:b) ){b@}13cF
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c HZ:6zH
7、说明:在线视图查询(表名1:a ) g?ULWeZg5
select * from (SELECT a,b,c FROM a) T where t.a > 1; &oX>*6L
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 ^cuc.g)c$?
select * from table1 where time between time1 and time2 )h)]SF}
select a,b,c, from table1 where a not between 数值1 and 数值2 (}2~<
9、说明:in 的使用方法 % S os
select * from table1 where a [not] in ('值1','值2','值4','值6') .*)2SNH
10、说明:两张关联表,删除主表中已经在副表中没有的信息 a8UwhjFO
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7K98#;a)5
11、说明:四表联查问题: :\o {_
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... VF ys.=
12、说明:日程安排提前五分钟提醒 H7DJ~z~J
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 >o=-$gz`
13、说明:一条sql 语句搞定数据库分页 #}y2)g
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 BGX.U\uc
14、说明:前10条记录 {.INnFGP@)
select top 10 * form table1 where 范围 nX`u[ks
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.) ]@u6HH~^
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +csi[c)3E
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 #%h-[/
(select a from tableA ) except (select a from tableB) except (select a from tableC) h3xAJ!
17、说明:随机取出10条数据 *vwbgJG! *
select top 10 * from tablename order by newid() 73\JwOn~
18、说明:随机选择记录 >: g3k
select newid() R)m'lMi|
19、说明:删除重复记录 D-._z:_
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +O?KNZ
20、说明:列出数据库里所有的表名 =7m)sxj]w
select name from sysobjects where type='U' ~o~!+`@q
21、说明:列出表里的所有的 pWJFz-
select name from syscolumns where id=object_id('TableName') OD!& .%
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。 <d$x.in
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type CTZ8Da^
显示结果: O*FUTZd( J
type vender pcs 7x%R:^*4
电脑 A 1 }WH&iES@P
电脑 A 1 &n8_0|gK
光盘 B 2
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光盘 A 2 1 P!Yxeh
手机 B 3 Yz+ZY
手机 C 3
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23、说明:初始化表table1
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TRUNCATE TABLE table1 1^}[&ar
24、说明:选择从10到15的记录 |$
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc @X;!92i
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三、技巧 KJaXg;,H
1、1=1,1=2的使用,在SQL语句组合时用的较多 wMg0>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, !`Hd-&}bYz
如: f@|A[>"V
if @strWhere !='' J`].:IOh
begin "ozr+:#\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere t^G"f;Ra+
end &keR~~/
else eEv@}1~
begin M:[ %[+6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' I7n"&{s"*
end naR0@Q"\h
我们可以直接写成 +{f:cea (1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere @a0DT=>dT
2、收缩数据库 (G;lx
--重建索引 U`NjPZe5^
DBCC REINDEX po2!
DBCC INDEXDEFRAG %D%8^Zd_
--收缩数据和日志 biU^[g("
DBCC SHRINKDB -7@/[9Gf`:
DBCC SHRINKFILE b((M)Gz
3、压缩数据库 {CGUL|y
dbcc shrinkdatabase(dbname) _C*fs<#
4、转移数据库给新用户以已存在用户权限 tnN.:%mZ
exec sp_change_users_login 'update_one','newname','oldname' nz=GlO'[
go q(.sq12<<W
5、检查备份集 E%,^Yvh/
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' FE (ev 9@
6、修复数据库 i/`m`qdg
ALTER DATABASE [dvbbs] SET SINGLE_USER #Oc]
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GO j2StXq3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 7`zHX&-W
GO ?IqQ-C)6D
ALTER DATABASE [dvbbs] SET MULTI_USER pS'FI@.'{
GO Y4`}y-'d
7、日志清除 jZ~n[
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SET NOCOUNT ON 2q=AEv/
DECLARE @LogicalFileName sysname, g+Sbl
@MaxMinutes INT, <oT^ A|JFj
@NewSize INT aJbO((%$|u
USE tablename -- 要操作的数据库名 x7!L{(E3
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 <66X Xh.
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 7e|s
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@NewSize = 1 -- 你想设定的日志文件的大小(M) 0zlb0[
-- Setup / initialize |@
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DECLARE @OriginalSize int F@'Jbd`
SELECT @OriginalSize = size BW}U%B^.
FROM sysfiles W14
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WHERE name = @LogicalFileName !Sh&3uy_qN
SELECT 'Original Size of ' + db_name() + ' LOG is ' + p6#g;$V$
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + i1NY9br
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' D%OQ e#!
FROM sysfiles |y!=J$$_H
WHERE name = @LogicalFileName /v1Q4mq
CREATE TABLE DummyTrans w[zjerH3
(DummyColumn char (8000) not null) =hC,@R>;
DECLARE @Counter INT, 93("oBd[s(
@StartTime DATETIME, 1{ ~#H<K
@TruncLog VARCHAR(255) p.v0D:@&
SELECT @StartTime = GETDATE(), s
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 8D3OOab
DBCC SHRINKFILE (@LogicalFileName, @NewSize) mS$j?>m
EXEC (@TruncLog) K/j3a[.
-- Wrap the log if necessary. A@1W}8qY:
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Z<1FSk,[
AND (@OriginalSize * 8 /1024) > @NewSize "U>JM@0DNm
BEGIN -- Outer loop. 4:$4u@
SELECT @Counter = 0 Ai=se2
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Pq;U&,
BEGIN -- update G'Q-An%z
INSERT DummyTrans VALUES ('Fill Log') fTS5yb%
DELETE DummyTrans JQ8fdP A
SELECT @Counter = @Counter + 1 r@h5w_9
END q<[P6}.
EXEC (@TruncLog) xW)2<m6C&
END ;qafT@
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + .h@rLorm>
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 4B =7:r
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' nm5cpnNl
FROM sysfiles o{* e'4
WHERE name = @LogicalFileName QdH\LL^8R4
DROP TABLE DummyTrans V:In>u$QJ!
SET NOCOUNT OFF );
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8、说明:更改某个表 z&#SPH*
exec sp_changeobjectowner 'tablename','dbo' 8uc1iB
9、存储更改全部表 +Mo9kC
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ov`h
@OldOwner as NVARCHAR(128), p
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@NewOwner as NVARCHAR(128) ^ =bu(L
AS :mh_G
DECLARE @Name as NVARCHAR(128) m4hX 'F
DECLARE @Owner as NVARCHAR(128) E4`N-3
DECLARE @OwnerName as NVARCHAR(128) ]/[FR 5>
DECLARE curObject CURSOR FOR m[?E
select 'Name' = name, |oH,
'Owner' = user_name(uid) #%a;"w
from sysobjects jaTh^L
where user_name(uid)=@OldOwner &zl|87M
order by name 5{|7$VqPF
OPEN curObject gf#{k2r
FETCH NEXT FROM curObject INTO @Name, @Owner -BrMp%C
WHILE(@@FETCH_STATUS=0) 4IB9,?p
BEGIN p `8s
if @Owner=@OldOwner 0bceI
begin gn8R[5:!V
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Uol|9F
exec sp_changeobjectowner @OwnerName, @NewOwner 1n >X[!
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end AF;)#T<
-- select @name,@NewOwner,@OldOwner rn/ /%
FETCH NEXT FROM curObject INTO @Name, @Owner <r.)hT"0
END bR*-Ht+wd
close curObject KyVQh8
deallocate curObject ocqU=^ta
GO 1tEgl\u\
10、SQL SERVER中直接循环写入数据 wKtl+}}
declare @i int kw>v:F<M
set @i=1 W]"zctE
while @i<30 Tzt8h\Q^z
begin -[*,^Ti`
insert into test (userid) values(@i) SN9kFFIPb=
set @i=@i+1 m'Amli@[
end ''q@>
小记存储过程中经常用到的本周,本月,本年函数 O,+1<.;+
Dateadd(wk,datediff(wk,0,getdate()),-1) $?
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Dateadd(wk,datediff(wk,0,getdate()),6) b*;Si7-
Dateadd(mm,datediff(mm,0,getdate()),0) 9oyE$S h]
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 04LI]'
Dateadd(yy,datediff(yy,0,getdate()),0) .f*4T4eR-
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Ye"o6_U"
上面的SQL代码只是一个时间段 Eza`Z`
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Dateadd(wk,datediff(wk,0,getdate()),-1) N|8P)
Dateadd(wk,datediff(wk,0,getdate()),6) <":;+Ng+
就是表示本周时间段. dbwe?ksh
下面的SQL的条件部分,就是查询时间段在本周范围内的: qW$<U3u}
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Ff$L|
而在存储过程中 AsQ)q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?x$"+,
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) i2@VB6]?