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。 ;TC]<N.YJT
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一、基础 'b" 7Lzp2
1、说明:创建数据库 w('}QB`xad
CREATE DATABASE database-name Za?BpV~
2、说明:删除数据库 >bI\pJ
drop database dbname pm9sI4S
3、说明:备份sql server A.yIl`'UP#
--- 创建 备份数据的 device t(vyi
USE master \'zloBU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Jj0:p"
--- 开始 备份 \d.\M
BACKUP DATABASE pubs TO testBack 'ahz@+lO
4、说明:创建新表 vz3olHX
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) jZ"j_=o@
根据已有的表创建新表: #zgO_H
A:create table tab_new like tab_old (使用旧表创建新表) Migl
B:create table tab_new as select col1,col2... from tab_old definition only DD
5、说明:删除新表 CX2qtI8N?
drop table tabname FQ0 ;%Z
6、说明:增加一个列 d~6UJ=]@8
Alter table tabname add column col type N/#x
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。 "5ISKuL
7、说明:添加主键: Alter table tabname add primary key(col) `wIWK7i
说明:删除主键: Alter table tabname drop primary key(col) C2b<is=H:
8、说明:创建索引:create [unique] index idxname on tabname(col....) a".iVf6y
删除索引:drop index idxname zRgGSxn
注:索引是不可更改的,想更改必须删除重新建。 ZmkH55Cn
9、说明:创建视图:create view viewname as select statement FWp ?l
删除视图:drop view viewname ^Nds@MR{8'
10、说明:几个简单的基本的sql语句 cM<08-:v
选择:select * from table1 where 范围 4Wvefq"
插入:insert into table1(field1,field2) values(value1,value2) oV9{{
删除:delete from table1 where 范围 M@G\b^ "
更新:update table1 set field1=value1 where 范围 "9X!Ewm"P
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Pd;8<UMk
排序:select * from table1 order by field1,field2 [desc] `2\:b^h
总数:select count as totalcount from table1 mBB"e"o
求和:select sum(field1) as sumvalue from table1 hW~UJ/$
平均:select avg(field1) as avgvalue from table1 <eS+3,
最大:select max(field1) as maxvalue from table1 OXl0R{4
最小:select min(field1) as minvalue from table1 MOytxl:R
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11、说明:几个高级查询运算词 F.@|-wq&
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A: UNION 运算符 2dB]Lw@s
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。 AuM}L&`i^
B: EXCEPT 运算符 C%ZPWOc_8
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。 <Voct
C: INTERSECT 运算符 WuI$
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。 A5\ Hq
注:使用运算词的几个查询结果行必须是一致的。 n
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12、说明:使用外连接 MO| Dwuaf
A、left outer join: CbxWK#aMmB
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。 _KT'W!7
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 7 _"G@h
B:right outer join: )_>'D4l?
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。 b>#=7;
C:full outer join: ZP@NV|B
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。 De{ZQg)
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二、提升 f)Y~F/[$P
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) :AQ9-&i/a-
法一:select * into b from a where 1<>1 3 _!MVT
法二:select top 0 * into b from a ,_<|e\>~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) X(.[rC>
insert into b(a, b, c) select d,e,f from b; .r-Zz3
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) " j_cI-@6
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6kAGOjO
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. @w(|d<5l:L
4、说明:子查询(表名1:a 表名2:b) 1*6xFn
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 9&6P,ts%Q
5、说明:显示文章、提交人和最后回复时间 wZJbI[r
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b k=d0%}
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6、说明:外连接查询(表名1:a 表名2:b) %\}5u[V
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c AOwmPHEL
7、说明:在线视图查询(表名1:a ) sX}#L
select * from (SELECT a,b,c FROM a) T where t.a > 1; 0S&J=2D!
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 [}l 90 lP
select * from table1 where time between time1 and time2 FJKlqM5]
select a,b,c, from table1 where a not between 数值1 and 数值2 Jf#-OlEQ
9、说明:in 的使用方法 0V8 6]zSo
select * from table1 where a [not] in ('值1','值2','值4','值6') _I3v"d
10、说明:两张关联表,删除主表中已经在副表中没有的信息 (u='&ka
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) /?b{*<TK
11、说明:四表联查问题: R>&8%%#
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... \L}7.fkb8
12、说明:日程安排提前五分钟提醒 l,3,$
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 R[*n3
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13、说明:一条sql 语句搞定数据库分页 !g)rp`?
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 ,)TnIByM
14、说明:前10条记录 %]4=D)Om
select top 10 * form table1 where 范围 2 J3/Eu
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.) i]4n YYS
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~J5B?@2hK
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 C(z'oi:f
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?<\2}1
17、说明:随机取出10条数据 g>gf-2%Uo
select top 10 * from tablename order by newid() O(e!Vx{t!
18、说明:随机选择记录 M)Z!W3
select newid() x;/dSfv_
19、说明:删除重复记录 >Y+m54EE
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) O
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20、说明:列出数据库里所有的表名 DWCf+4
select name from sysobjects where type='U' >M##q?.
21、说明:列出表里的所有的 B[#n,ay
select name from syscolumns where id=object_id('TableName') W:9l"'
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。 AGO"),
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 V,8Z!.MG
显示结果: :>_oOn[ _
type vender pcs *DZ7,$LQ~D
电脑 A 1 \}Iq-Je
电脑 A 1 Y7I\<JG<
光盘 B 2 0V^I.S/q
光盘 A 2 tTubW=H
手机 B 3 CBpwtI>p
手机 C 3 iE_[]Vgc
23、说明:初始化表table1 "Y4glomR[
TRUNCATE TABLE table1 3-1a+7fD
24、说明:选择从10到15的记录 .j>MsQP#\C
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc OA} r*Wz
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三、技巧 6-g>(g
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]|=`-)AP3
"where 1=1" 是表示选择全部 "where 1=2"全部不选, yx*<c#Uf
如: ty4R2LnC
if @strWhere !='' ro3%VA=V
begin 0_Elxc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /iAhGY
end $e,r>tgD
else j+q)
begin cD)9EFo
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' H5
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end WU@_aw[
我们可以直接写成 c5 AaUza
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Q"c/]Sk)
2、收缩数据库 \i}-Y[Dg
--重建索引 Aho*E9VW
DBCC REINDEX \DBEs02
DBCC INDEXDEFRAG fOdqr
--收缩数据和日志 }QQ 7jE
DBCC SHRINKDB `R7dn/
DBCC SHRINKFILE ^K_FGE0ec
3、压缩数据库 h;y}g/HZ
dbcc shrinkdatabase(dbname) Qe4 % A
4、转移数据库给新用户以已存在用户权限 X%N!gy
exec sp_change_users_login 'update_one','newname','oldname' ._<,
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go +uTl
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5、检查备份集 )l!`k
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' D&G?Klq
6、修复数据库 Uq{$j5p8
ALTER DATABASE [dvbbs] SET SINGLE_USER @#-\BQ;
GO -Lb7=98
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK i:jB
GO Dsc0;7~6
ALTER DATABASE [dvbbs] SET MULTI_USER njO~^Hl7
GO G!G:YVWXP
7、日志清除 :2/jI:L~
SET NOCOUNT ON .}Ys+d1b9c
DECLARE @LogicalFileName sysname, E`hR(UL
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@MaxMinutes INT, euRKYGW
@NewSize INT GRVF/hPn
USE tablename -- 要操作的数据库名 Qb55q`'z
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 #a2Z.a<V
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 7zA+UWr
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2+S+Y%~
-- Setup / initialize 4GG>n
DECLARE @OriginalSize int A=Hv}lv
SELECT @OriginalSize = size 3^-R_
FROM sysfiles 6K<o0=,jm2
WHERE name = @LogicalFileName F< 5kcu#iL
SELECT 'Original Size of ' + db_name() + ' LOG is ' + gy~2LY !}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + aJF/y3
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7#oq|5
FROM sysfiles G51-CLM,
WHERE name = @LogicalFileName ST~YO
CREATE TABLE DummyTrans #Ufb
(DummyColumn char (8000) not null) &5bIM>)v
DECLARE @Counter INT, !<VP[%2L~
@StartTime DATETIME, L+T7Ge
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@TruncLog VARCHAR(255) 1@|%{c&+9
SELECT @StartTime = GETDATE(), .a(G=fk
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' .3XiL=^~Qp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) yJO Jw o^
EXEC (@TruncLog) &)JoB
-- Wrap the log if necessary. /FpPf[
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired $sg- P|Wo
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) e6tU8`z
AND (@OriginalSize * 8 /1024) > @NewSize
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BEGIN -- Outer loop. N#)Klq87z
SELECT @Counter = 0 }R5EuR m\
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) `d4xX@
BEGIN -- update x
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INSERT DummyTrans VALUES ('Fill Log') gd#?rc*f<3
DELETE DummyTrans M8 \/[R\
SELECT @Counter = @Counter + 1 v@8SMOe%
END a}|<*!4zUQ
EXEC (@TruncLog) ' S,g3
END gzH;`,
SELECT 'Final Size of ' + db_name() + ' LOG is ' + * a1q M?
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + `k8j FB C
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' BD}%RTeWKq
FROM sysfiles NV?XZ[<*<
WHERE name = @LogicalFileName J kAd3ls
DROP TABLE DummyTrans ZqpK}I
SET NOCOUNT OFF c=bK_Z_
8、说明:更改某个表 Hg8
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exec sp_changeobjectowner 'tablename','dbo' +Zr~mwM=x
9、存储更改全部表 |M
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ePI N<F;I
@OldOwner as NVARCHAR(128), |;t{L^
@NewOwner as NVARCHAR(128) PNo:vRtsq
AS Y}s6__
DECLARE @Name as NVARCHAR(128) ,L~aa?Nb-
DECLARE @Owner as NVARCHAR(128) 8y_(Iu|:
DECLARE @OwnerName as NVARCHAR(128) c9Cc%EK
DECLARE curObject CURSOR FOR xx7&y!_
select 'Name' = name, %21 |-B
'Owner' = user_name(uid) ht>/7.p]
from sysobjects n_ ?+QF
where user_name(uid)=@OldOwner PO0Od z
order by name nR@mm
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OPEN curObject q@XJ,e1A
FETCH NEXT FROM curObject INTO @Name, @Owner *icaKy3
WHILE(@@FETCH_STATUS=0) ?[>Y@we
BEGIN _y>drvg
if @Owner=@OldOwner F$1{w"&
begin 5WxNH}{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) (a-Lx2 T
exec sp_changeobjectowner @OwnerName, @NewOwner z
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end S
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-- select @name,@NewOwner,@OldOwner F0zaA
FETCH NEXT FROM curObject INTO @Name, @Owner HrFbUK@@
END vfx{:3fO
close curObject 3&{6+ A
deallocate curObject ~]?EV?T
GO y:$qX*+9e
10、SQL SERVER中直接循环写入数据 9,\AAISi
declare @i int "iX\U'`
set @i=1 r2i]9>w
while @i<30 p}/D{|xO
begin g+QIhur
insert into test (userid) values(@i) Bj><0
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set @i=@i+1 n&|N=zh
end SAf)#HXa
小记存储过程中经常用到的本周,本月,本年函数 /n>vPJvz
Dateadd(wk,datediff(wk,0,getdate()),-1) .'38^
Dateadd(wk,datediff(wk,0,getdate()),6) IuAu_`,Ndi
Dateadd(mm,datediff(mm,0,getdate()),0) `U\l: ~]e
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) T3"'`Sd9;
Dateadd(yy,datediff(yy,0,getdate()),0) B~qo^ppVU
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) i!3*)-a\~`
上面的SQL代码只是一个时间段 H_x}-
Dateadd(wk,datediff(wk,0,getdate()),-1) p W5D!z
Dateadd(wk,datediff(wk,0,getdate()),6) j;D$qd'J
就是表示本周时间段. D0kz;X
下面的SQL的条件部分,就是查询时间段在本周范围内的: uW/>c$*)
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) [P ;fv
而在存储过程中 BzWkZAX
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?2,D-3 {
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 0o6o<ggi