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。 1WLaJ%Fv
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一、基础 z<n&P7k5j
1、说明:创建数据库 "TePO7^m
CREATE DATABASE database-name SFa~j)9'n
2、说明:删除数据库 kV+O|9
drop database dbname ,$;pLjo6
3、说明:备份sql server :HDU\|{^
--- 创建 备份数据的 device 2< Q3-|/i
USE master >^%TY^7n
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' i@STo7=
--- 开始 备份 WhN~R[LE_
BACKUP DATABASE pubs TO testBack BFMINq>
4、说明:创建新表 CqbPUcK
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) OqA#4h4^
根据已有的表创建新表: OG}m+K&<
A:create table tab_new like tab_old (使用旧表创建新表) p*"H&xA@
B:create table tab_new as select col1,col2... from tab_old definition only E=8$*YUW(g
5、说明:删除新表 %P-z3 0FHp
drop table tabname d@_|
6、说明:增加一个列 uY Y{M`
Alter table tabname add column col type Kv-4VWh
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。 eh}{\P
7、说明:添加主键: Alter table tabname add primary key(col) 2 1]87$
说明:删除主键: Alter table tabname drop primary key(col) hha^:,
8、说明:创建索引:create [unique] index idxname on tabname(col....) w&^_2<a2
删除索引:drop index idxname 0|@*`-:VO
注:索引是不可更改的,想更改必须删除重新建。 TClgywL
9、说明:创建视图:create view viewname as select statement FTC,{$
删除视图:drop view viewname G,JNUok
10、说明:几个简单的基本的sql语句 x9VR>ux&
选择:select * from table1 where 范围 fr([g?F%D
插入:insert into table1(field1,field2) values(value1,value2) eU.HS78
删除:delete from table1 where 范围 q~*>
更新:update table1 set field1=value1 where 范围 w#\*{EN
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料!
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排序:select * from table1 order by field1,field2 [desc] u}I\!-EX!v
总数:select count as totalcount from table1 qx<h rC0Z&
求和:select sum(field1) as sumvalue from table1 \-~TW4dYe
平均:select avg(field1) as avgvalue from table1 Uk|(VR9
最大:select max(field1) as maxvalue from table1 nRlvW{p;
最小:select min(field1) as minvalue from table1 r__Y{&IO
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11、说明:几个高级查询运算词 Kn+m9
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A: UNION 运算符 {P@OV1
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。 COk;z.Kn
B: EXCEPT 运算符 1Ydym2
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。 maR5hgWCHe
C: INTERSECT 运算符 [<p7'n3x
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。 DKxzk~sOM
注:使用运算词的几个查询结果行必须是一致的。 XKt">W
12、说明:使用外连接 tW|K\NL
A、left outer join: Km9Y_`?
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。 yYM_
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 2dUVHu= +
B:right outer join: YFY$iN~B,
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。 ({_Dg43O'[
C:full outer join: ?E:L6,a
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。 C|W\qXCqu
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二、提升 m}dO\;
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !R.*Vn[
法一:select * into b from a where 1<>1 V"{+cPBO)
法二:select top 0 * into b from a uNSbAw3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) dJ}E,rW}
insert into b(a, b, c) select d,e,f from b; 4PzCm k
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) DoA+Bwq@
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 9dFSppM
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Z U^dLN-N
4、说明:子查询(表名1:a 表名2:b) u!VAAX
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) Q-g}{mFS
5、说明:显示文章、提交人和最后回复时间 2po>%Cp
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 1^4z/<ZWm
6、说明:外连接查询(表名1:a 表名2:b) N1O.U"L;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c b7_uT`<
7、说明:在线视图查询(表名1:a ) ToWtltCD
select * from (SELECT a,b,c FROM a) T where t.a > 1; $<(FZb=
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Zw`vPvb!
select * from table1 where time between time1 and time2 ;>duY\$<
select a,b,c, from table1 where a not between 数值1 and 数值2 !$i*u-%4
9、说明:in 的使用方法 <p74U( V
select * from table1 where a [not] in ('值1','值2','值4','值6') !K~:crUV|S
10、说明:两张关联表,删除主表中已经在副表中没有的信息
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) H=j&uv8
11、说明:四表联查问题: DZI:zsf;5Q
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 ..... |3A/Og
12、说明:日程安排提前五分钟提醒 oSOO5dk:z
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 xF4>D!T%8
13、说明:一条sql 语句搞定数据库分页 tgP x!5U
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 Y]SX2kk(2
14、说明:前10条记录 {:;599l
select top 10 * form table1 where 范围 *$I5_A8,.
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 8- U1Y
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Qwm#6{5
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 l"#}g%E
(select a from tableA ) except (select a from tableB) except (select a from tableC) boJ
17、说明:随机取出10条数据 A1A/OU<Vb
select top 10 * from tablename order by newid() %ur_DQ
18、说明:随机选择记录 Z`=[hu
select newid() '9Hah
19、说明:删除重复记录 IP]"D"
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 8 N5ga
20、说明:列出数据库里所有的表名 (A\p5@ht
select name from sysobjects where type='U' xA-u%Vf7@
21、说明:列出表里的所有的 Wp[R$/uT
select name from syscolumns where id=object_id('TableName') &Q85B q
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。 UE[5Bw?4X
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 qx $-% P
显示结果: k9ThWo/#u
type vender pcs K38A;=t9
电脑 A 1 ?x|8"*N
电脑 A 1 EN =oA P
光盘 B 2 0=2D90
光盘 A 2 v ;q<h
手机 B 3 8Q%rBl.
手机 C 3 J4-64t nZ
23、说明:初始化表table1 zdoJ+zRtK
TRUNCATE TABLE table1 xsPE UK&g
24、说明:选择从10到15的记录 oP$l( k
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc J4Ix\r_
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三、技巧 TfYXF`d
1、1=1,1=2的使用,在SQL语句组合时用的较多 K9#=@}!3L
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ]+SVQ|v0
如: Ez*9*]O*+
if @strWhere !='' >0W:snNK
begin o<hT/ P
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere u7oHqo`
end G8y:f%I!b
else QeK@++EVc
begin 1q])"l"<
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' <F=U(WWn9
end Yy$GfjJtL]
我们可以直接写成 Vd-\_VP20
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere d Q5_=(9
2、收缩数据库 /$
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--重建索引 H WOl79-
DBCC REINDEX ! f\q0Gnl
DBCC INDEXDEFRAG PfaBzi9?f
--收缩数据和日志 N6"b
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DBCC SHRINKDB |6%B2I&c
DBCC SHRINKFILE \BV$p2m5-
3、压缩数据库 \B0,?_i
dbcc shrinkdatabase(dbname) WW'8&:x
4、转移数据库给新用户以已存在用户权限 h@5mVTb}i
exec sp_change_users_login 'update_one','newname','oldname' 5ayM}u%\~
go ^r u1QDT
5、检查备份集 fgs){Ng`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 8| 6:
6、修复数据库 yA8e"$
ALTER DATABASE [dvbbs] SET SINGLE_USER rNgFsFQ>.
GO s<i& q {r
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK BM(8+Wj
GO ]}3AP!:
ALTER DATABASE [dvbbs] SET MULTI_USER zHI_U\"8D
GO =@ '>|-w|
7、日志清除 BI'}
SET NOCOUNT ON `uO(#au,U
DECLARE @LogicalFileName sysname, IA\CBwiLj
@MaxMinutes INT, O>Vb7`z0<
@NewSize INT \"]vSx>
USE tablename -- 要操作的数据库名 S1iF1X(+?X
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 pZS0;T]W,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. eY)JuJ?
@NewSize = 1 -- 你想设定的日志文件的大小(M) 03WLVP@
-- Setup / initialize l(EDe
DECLARE @OriginalSize int F__j]}?
SELECT @OriginalSize = size 3fS+,>s\O
FROM sysfiles HA?<j|M
WHERE name = @LogicalFileName _I$\O5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 7~2b4"&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + (vq0Gl
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' tgy= .o]
FROM sysfiles @a08*"lbp
WHERE name = @LogicalFileName G@YX8!wU
CREATE TABLE DummyTrans V
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(DummyColumn char (8000) not null) #1INOR9
DECLARE @Counter INT, 7QXA*.'
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@StartTime DATETIME, j-egsKR
@TruncLog VARCHAR(255) wA+QUN3#n
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' U*G8}W
DBCC SHRINKFILE (@LogicalFileName, @NewSize) BO#XQ,
EXEC (@TruncLog) C@{#OOa
-- Wrap the log if necessary. |i)7jG<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Lci SQ
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 3ErW3Ac Ou
AND (@OriginalSize * 8 /1024) > @NewSize I<v1S
BEGIN -- Outer loop. [Yo3=(7J
SELECT @Counter = 0 j.? '*?P
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) AY{-Hf&
BEGIN -- update 9~bl
INSERT DummyTrans VALUES ('Fill Log') E8[{U8)[;5
DELETE DummyTrans K%Dksx7ow
SELECT @Counter = @Counter + 1 G~SgI>Q
END [^rT: %Z
EXEC (@TruncLog) X@;o<2^
END v8
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + MIblx
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ^6tcB* #A
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' l98.Hb7
FROM sysfiles huMNt6P[
WHERE name = @LogicalFileName fOE8{O^W
DROP TABLE DummyTrans
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SET NOCOUNT OFF 5H (CP
8、说明:更改某个表 dKs^Dq
exec sp_changeobjectowner 'tablename','dbo' C$9+p@G6
9、存储更改全部表 ,QDS_u$xi&
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch r-27AJu
@OldOwner as NVARCHAR(128), LaI(
@NewOwner as NVARCHAR(128) /%E l0X
AS gk"0r\Eq
DECLARE @Name as NVARCHAR(128) L*;XjacI]
DECLARE @Owner as NVARCHAR(128) 4 1w*<{Lk
DECLARE @OwnerName as NVARCHAR(128) r:[N#*kK
DECLARE curObject CURSOR FOR 7+I%0U}m
select 'Name' = name, t<_Jx<{2
'Owner' = user_name(uid) :lF[k`S T
from sysobjects !ke_?+8sY
where user_name(uid)=@OldOwner wzLR]<6G
order by name v35wlt^}
OPEN curObject -&4W0JK9
FETCH NEXT FROM curObject INTO @Name, @Owner yv.Y-c=
WHILE(@@FETCH_STATUS=0) m!{}Y]FZn
BEGIN I)wjTTM5
if @Owner=@OldOwner 5|&:l8=
begin s0,\[rM
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *?;<buJb?
exec sp_changeobjectowner @OwnerName, @NewOwner OYcf+p"<\
end JfJUOaL
-- select @name,@NewOwner,@OldOwner +-b:XeHSZ
FETCH NEXT FROM curObject INTO @Name, @Owner ?y.q<F)
END h8IjTd]z{$
close curObject "qL4D4
deallocate curObject DU_38tz
GO Hwr#
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10、SQL SERVER中直接循环写入数据 HK@LA3
declare @i int t;[L-|^
set @i=1 RR2Q
while @i<30 k=t\
begin 5F@7A2ZR
insert into test (userid) values(@i) )XB31^
set @i=@i+1 O]ZP- WG
end ' 0iXx
小记存储过程中经常用到的本周,本月,本年函数 nWTo$*>W
Dateadd(wk,datediff(wk,0,getdate()),-1) HOWm""IkB
Dateadd(wk,datediff(wk,0,getdate()),6) S@AHI!"h=V
Dateadd(mm,datediff(mm,0,getdate()),0) x/nlIoT
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) f1cQ*#2~
Dateadd(yy,datediff(yy,0,getdate()),0) it=4cHT
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) fz%I'+!
上面的SQL代码只是一个时间段 E)eRi"a46
Dateadd(wk,datediff(wk,0,getdate()),-1) '4gi*8Y
Dateadd(wk,datediff(wk,0,getdate()),6) | aH;@V
就是表示本周时间段. j@4
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下面的SQL的条件部分,就是查询时间段在本周范围内的: ]Y#$!fIx
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Ri$wt.b
而在存储过程中 :HSqa9>wa
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ~ vD7BO`
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) //c<p