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。 (+dRD]|T
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一、基础 E e>j7k.G.
1、说明:创建数据库 -^v}T/Kl#
CREATE DATABASE database-name rrYp^xLa`
2、说明:删除数据库 Q%Q?q)x
drop database dbname om?CFl
3、说明:备份sql server T0%TeFY
--- 创建 备份数据的 device !U:s.^{
USE master XWpnZFjE
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;bX
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--- 开始 备份 J5_Y\@
BACKUP DATABASE pubs TO testBack :
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4、说明:创建新表
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) QYXx7h r=$
根据已有的表创建新表: 5KE%@,k k
A:create table tab_new like tab_old (使用旧表创建新表) _x6E_i-(
B:create table tab_new as select col1,col2... from tab_old definition only gecT*^
5、说明:删除新表 z.&%>%TPP
drop table tabname k<zGrq=8J
6、说明:增加一个列 {))S<_yN
Alter table tabname add column col type b.q"s6u
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。 e uHu}
7、说明:添加主键: Alter table tabname add primary key(col) `)M\(_
说明:删除主键: Alter table tabname drop primary key(col) vx}Z
8、说明:创建索引:create [unique] index idxname on tabname(col....) "UGj4^1f
删除索引:drop index idxname nvo1+W(%
注:索引是不可更改的,想更改必须删除重新建。 y6jmn1K
9、说明:创建视图:create view viewname as select statement /3Ix,7
删除视图:drop view viewname
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10、说明:几个简单的基本的sql语句 =z1o}ga=EA
选择:select * from table1 where 范围 oEoJa:h
插入:insert into table1(field1,field2) values(value1,value2) 0gD59N'C
删除:delete from table1 where 范围 ivz9R'
更新:update table1 set field1=value1 where 范围 &Z;8J @
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! [2 w<F[
排序:select * from table1 order by field1,field2 [desc] |4> r"
总数:select count as totalcount from table1 iSz@E&[X
求和:select sum(field1) as sumvalue from table1 0!,gT H>
平均:select avg(field1) as avgvalue from table1 :8Ts'OGwI
最大:select max(field1) as maxvalue from table1 roj04|
最小:select min(field1) as minvalue from table1 ca3BJWY}J
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11、说明:几个高级查询运算词 9#T%bB"J
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A: UNION 运算符 `TD%M`a
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。 >+jbMAYSq
B: EXCEPT 运算符 eIUuq&(
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。 CziaxJ
C: INTERSECT 运算符 5Jhbf2-
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。 k CW!m
注:使用运算词的几个查询结果行必须是一致的。
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12、说明:使用外连接 E7NbPNd
A、left outer join: 2VV[*QI
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 j@C0
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 s 9|a2/{
B:right outer join: 3aE[F f[
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。 "gbnLKs
C:full outer join: cbu nq"
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。 mU3Y)
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二、提升 y@kcXlY
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) juYA`:qE&
法一:select * into b from a where 1<>1 Cwsoz
法二:select top 0 * into b from a Ku0H?qft(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) z>mZT.
insert into b(a, b, c) select d,e,f from b; cbh#E)['
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) %uz|NRB=
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 dE5 5
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ,a9D~i 9R
4、说明:子查询(表名1:a 表名2:b) 8!uL-_ Bn
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) z{`6#
5、说明:显示文章、提交人和最后回复时间 +U+aWk
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 2;%#C!TG;
6、说明:外连接查询(表名1:a 表名2:b) 49xp2{
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c k(-Z@
7、说明:在线视图查询(表名1:a ) wuIsO;}/9
select * from (SELECT a,b,c FROM a) T where t.a > 1; 1Nl&4 YLO
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 o<D3Y95b
select * from table1 where time between time1 and time2 ~@-QbkC
select a,b,c, from table1 where a not between 数值1 and 数值2 5Cc6,
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9、说明:in 的使用方法 P1 7> 6)a
select * from table1 where a [not] in ('值1','值2','值4','值6') 5:*5j@/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 &\"Y/b]
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ]r/(n]=(
11、说明:四表联查问题: HUU >hq9
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 ..... FylWbQU9
12、说明:日程安排提前五分钟提醒 VD9
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 |'U,/
13、说明:一条sql 语句搞定数据库分页 k_*XJ <S!Y
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 C
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14、说明:前10条记录 k
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select top 10 * form table1 where 范围 Xzx[C_G
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.) DL'd&;6
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $kxu;I
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 [<D+pqh
(select a from tableA ) except (select a from tableB) except (select a from tableC) ur/Oc24i1n
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() PoYr:=S?
18、说明:随机选择记录 vQ:x%=]
select newid() 4r_!>['`"
19、说明:删除重复记录 y!7B,
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) F3r S6_
20、说明:列出数据库里所有的表名 8`:M\*
select name from sysobjects where type='U' gf:vb*#Wa
21、说明:列出表里的所有的 qxf+#
select name from syscolumns where id=object_id('TableName') 5*JV )[
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 D-Bv(/Pz]$
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 =:4'
显示结果: "NxOOLL
type vender pcs R&NpdW N
电脑 A 1 @
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电脑 A 1 >lA7*nn
光盘 B 2 jmRhAJV
光盘 A 2 f|X[gL,B
手机 B 3 sEoZ1E
手机 C 3 hX0RET
23、说明:初始化表table1 ,"@w>WL<9
TRUNCATE TABLE table1 a;56k
24、说明:选择从10到15的记录 G{F6
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ])N|[ |$
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三、技巧 Xf6fH O
1、1=1,1=2的使用,在SQL语句组合时用的较多 vz6SCGg,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, UV?[d:\>'
如: M,&tA1CH
if @strWhere !='' W7%p^;ZQ$
begin A)OdQFet(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere S2Zx &D/_
end %'$f ?y
else DD2adu^
begin =nLO?qoe
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' XxhsPFv
end "PMO
我们可以直接写成 {":c@I
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6@&fvf
2、收缩数据库 !syU]Yk
--重建索引 pV8[l) J
DBCC REINDEX 7kdeYr~<1
DBCC INDEXDEFRAG HB%K|&!+
--收缩数据和日志 N A8
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DBCC SHRINKDB b~1iPaIh
DBCC SHRINKFILE YmOldR9v(
3、压缩数据库
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dbcc shrinkdatabase(dbname) Bu&So|@TL
4、转移数据库给新用户以已存在用户权限 '[%jjUU
exec sp_change_users_login 'update_one','newname','oldname' Qr<AV:
go 1y7y0V
5、检查备份集 87pnSj/X"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' lBS"3s384
6、修复数据库 \Ps5H5Qk;
ALTER DATABASE [dvbbs] SET SINGLE_USER >8%M*-=p
GO / HL_$g<
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w:v=se"U
GO HV8I nodi
ALTER DATABASE [dvbbs] SET MULTI_USER w"1x=+
GO d<!IGt4Ky
7、日志清除 MBlBMUJk
SET NOCOUNT ON B&
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DECLARE @LogicalFileName sysname, 0',[J
@MaxMinutes INT, D '<$ g
@NewSize INT ;ed#+$Na
USE tablename -- 要操作的数据库名 >:A<"wZ
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \Y+")
@MaxMinutes = 10, -- Limit on time allowed to wrap log. +^Fp&K+^
@NewSize = 1 -- 你想设定的日志文件的大小(M) ~JLYhA^'+<
-- Setup / initialize Gy9
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DECLARE @OriginalSize int 5}
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SELECT @OriginalSize = size 7_KXD#
FROM sysfiles CG.,/]_
WHERE name = @LogicalFileName z{=v)F5y
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 0Q`&inwh
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + )(lJT&e
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' VtWT{y5Ec
FROM sysfiles !j0_
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WHERE name = @LogicalFileName ,m:L2 -J@
CREATE TABLE DummyTrans zSKKr?{
(DummyColumn char (8000) not null) _KN:
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DECLARE @Counter INT, yyjw?#\8
@StartTime DATETIME, O>%$q8x@i
@TruncLog VARCHAR(255) (xu=%
SELECT @StartTime = GETDATE(), 4vLw?_".
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' l~D\;F
DBCC SHRINKFILE (@LogicalFileName, @NewSize) $it@>L8
EXEC (@TruncLog) l#$TYJi
-- Wrap the log if necessary. n+rM"Gxz
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8ljuc5,J
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) AuXs B
AND (@OriginalSize * 8 /1024) > @NewSize Mb.4J2F ?
BEGIN -- Outer loop. Yz\
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SELECT @Counter = 0 7h`^N5H.q
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) IJ_ m
BEGIN -- update tDt
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INSERT DummyTrans VALUES ('Fill Log') #ua^{OrC/
DELETE DummyTrans /tZ0
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SELECT @Counter = @Counter + 1 ot }6D
END c]NN'9G!{
EXEC (@TruncLog) x[x(y{&~
END W-m"@<Z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + "mA1H]r3
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + B`1kG Ex .
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' kC`Rd:5
FROM sysfiles uY]0dyI
WHERE name = @LogicalFileName hl]S'yr
DROP TABLE DummyTrans i/*,N&^
SET NOCOUNT OFF Y{+3}drJE
8、说明:更改某个表 ]]PE#DDg
exec sp_changeobjectowner 'tablename','dbo' y\,f6=%k
9、存储更改全部表 fEwifSp.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch $8g42LR'
@OldOwner as NVARCHAR(128), x<>YUw8`
@NewOwner as NVARCHAR(128) d.AC%&W
AS Z0\Iyc G
DECLARE @Name as NVARCHAR(128) KUKI qAA
DECLARE @Owner as NVARCHAR(128) :tbd,Uo
DECLARE @OwnerName as NVARCHAR(128) CA*~2|
DECLARE curObject CURSOR FOR 6|#g+&[
select 'Name' = name, H+x#gK2l
'Owner' = user_name(uid) YPEnNt+
from sysobjects FmD +8=
where user_name(uid)=@OldOwner 1tGgDbJU
order by name [.-a$J[4+F
OPEN curObject gDC2
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FETCH NEXT FROM curObject INTO @Name, @Owner Hi8Y6|y$D
WHILE(@@FETCH_STATUS=0) t!qwxX*$T
BEGIN Y;_T=L
if @Owner=@OldOwner V.VJcx
begin t$I|E
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Z@M6!;y#
exec sp_changeobjectowner @OwnerName, @NewOwner Ep ">v>"
end Uk'U?9O
-- select @name,@NewOwner,@OldOwner }_%P6
FETCH NEXT FROM curObject INTO @Name, @Owner wW5Yw
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END 8Z8Y[p
close curObject zy>}L #
deallocate curObject l$M +.GB<
GO 1<,/
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10、SQL SERVER中直接循环写入数据 A*i_|]Q
declare @i int ^yVl"/
set @i=1 KB[QZ`"%!
while @i<30 CDCC1B G"
begin c-*2dV[@
insert into test (userid) values(@i) Dbz]{_Y;
set @i=@i+1 c;!9 \1sr
end '[fZt#
小记存储过程中经常用到的本周,本月,本年函数 WQKj]:qk0
Dateadd(wk,datediff(wk,0,getdate()),-1) ~gdd cTp
Dateadd(wk,datediff(wk,0,getdate()),6) KlO(o#&N
Dateadd(mm,datediff(mm,0,getdate()),0) ( 3;`bvYH"
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) T|bZ9_?+2
Dateadd(yy,datediff(yy,0,getdate()),0) /80YZ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) D^$OCj\
上面的SQL代码只是一个时间段 # ZTLrq5b
Dateadd(wk,datediff(wk,0,getdate()),-1) X4Xf2aXI
Dateadd(wk,datediff(wk,0,getdate()),6) LdEE+"Jw
就是表示本周时间段. H.~bD[gA
下面的SQL的条件部分,就是查询时间段在本周范围内的:
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) n(R_#,Hs
而在存储过程中 bU+9Gi@v
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) [`nY2[A$
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) XKSX#cia