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。 %iPWg
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一、基础 TWZ**S-
1、说明:创建数据库 _zvCc%
CREATE DATABASE database-name %@k@tD6
2、说明:删除数据库 PzMJ^H{
drop database dbname m(i8 4~
3、说明:备份sql server /Nt#|C>
--- 创建 备份数据的 device 7/&i'y
USE master 3LN+gXmU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ]w`)"{j5m
--- 开始 备份 <2"' R(4",
BACKUP DATABASE pubs TO testBack ?x1sm"]p'
4、说明:创建新表 L-?
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) zkt`7Pg;J
根据已有的表创建新表: v[{g"C
A:create table tab_new like tab_old (使用旧表创建新表) z6)b XL[f
B:create table tab_new as select col1,col2... from tab_old definition only *:gx1wd
5、说明:删除新表 t~]n"zgovz
drop table tabname rofj&{w
6、说明:增加一个列 `u$
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Alter table tabname add column col type VHyH't_&s
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。 X'Q?Mh
7、说明:添加主键: Alter table tabname add primary key(col) e=Ko4Ao2y
说明:删除主键: Alter table tabname drop primary key(col) <`rmQ`(}s
8、说明:创建索引:create [unique] index idxname on tabname(col....) %A64AJZ
删除索引:drop index idxname KSDz3qe
注:索引是不可更改的,想更改必须删除重新建。 b+Sq[
9、说明:创建视图:create view viewname as select statement `?E|frz[
删除视图:drop view viewname `?f6~$1
10、说明:几个简单的基本的sql语句 n_QSuh/Wn
选择:select * from table1 where 范围 )O\w'|$G
插入:insert into table1(field1,field2) values(value1,value2) 10R#}~D
删除:delete from table1 where 范围 w"ZngrwBl
更新:update table1 set field1=value1 where 范围 ndg1E;>
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! S52'!WTq
排序:select * from table1 order by field1,field2 [desc] VzD LG LH
总数:select count as totalcount from table1 J_NY:B
求和:select sum(field1) as sumvalue from table1 '2Q[g0VR
平均:select avg(field1) as avgvalue from table1 {*mf Is
最大:select max(field1) as maxvalue from table1 7+
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最小:select min(field1) as minvalue from table1 K</EVt,U~
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11、说明:几个高级查询运算词 /5:2g#S4
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A: UNION 运算符 6<1
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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。 /JsA[}.6
B: EXCEPT 运算符 kZ<0|b
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。 yX9 .yq
C: INTERSECT 运算符
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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。 la4
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注:使用运算词的几个查询结果行必须是一致的。 PWci D '!
12、说明:使用外连接 6`Hd)T5{w
A、left outer join: @=_4i&]$
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。 I;1W6uD=
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 |BGB60}]f
B:right outer join: |"}oGL6-
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。 Ey|{yUmU+
C:full outer join: &3gC&b^i
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。 4g4[n7
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二、提升 {E=BFs
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) $, hHR:
法一:select * into b from a where 1<>1 zUuOX5-6x
法二:select top 0 * into b from a gGZ-B<
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) t57MKDn
insert into b(a, b, c) select d,e,f from b; s>J\h
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) 6-E>-9]'E
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 7N:3
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. TOT#l6yqdd
4、说明:子查询(表名1:a 表名2:b) M(
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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) nA*Udrcn
5、说明:显示文章、提交人和最后回复时间 4y*"w*L
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Nk63F&J7e
6、说明:外连接查询(表名1:a 表名2:b) *^y,Gg/
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c `D/<*e,#
7、说明:在线视图查询(表名1:a ) W&~\@j]!D
select * from (SELECT a,b,c FROM a) T where t.a > 1; =[JstiT?E
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 ycq+C8J+Ep
select * from table1 where time between time1 and time2 n(uzqd
select a,b,c, from table1 where a not between 数值1 and 数值2 b~$8<\
9、说明:in 的使用方法 [>$?/DM
select * from table1 where a [not] in ('值1','值2','值4','值6') 35Ro85j
10、说明:两张关联表,删除主表中已经在副表中没有的信息 N\l|3~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) \LG0
11、说明:四表联查问题: IA%|OVAfF
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 ..... ~=GwNo_
12、说明:日程安排提前五分钟提醒 B4@1WZn<8
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 e&@;hDmIX
13、说明:一条sql 语句搞定数据库分页 X9
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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 3</W}]$)p
14、说明:前10条记录 MJ"@
select top 10 * form table1 where 范围 +D+v j|fn
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) *82+GY]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) >:Y"DX-
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 zMke}2
(select a from tableA ) except (select a from tableB) except (select a from tableC) FEH+ PKSc
17、说明:随机取出10条数据 |)VNf.aJZ
select top 10 * from tablename order by newid() aT4I sPA?_
18、说明:随机选择记录 t|urvoz
select newid() ~6A;H$dr
19、说明:删除重复记录 Sw.k,p*r
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 2P/ Sq
20、说明:列出数据库里所有的表名 ?;]Xc~
select name from sysobjects where type='U' _Z>ny&
21、说明:列出表里的所有的 q2b>Z6!5
select name from syscolumns where id=object_id('TableName') 8vkCmV
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。 s"UUo|hM
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 ++sbSl)Q
显示结果: j/t)=c
type vender pcs T mK[^
电脑 A 1 :F8h}\a*
电脑 A 1 \G0YLV~>P
光盘 B 2 Spu>
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光盘 A 2 s6F0&L;N&
手机 B 3 A^c
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手机 C 3 (`&SV$m
23、说明:初始化表table1 .],:pL9d
TRUNCATE TABLE table1 *Sg6VGP
24、说明:选择从10到15的记录 HV&i! M@T
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc U5
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三、技巧 Cxd^i
1、1=1,1=2的使用,在SQL语句组合时用的较多 h,\5C/
"where 1=1" 是表示选择全部 "where 1=2"全部不选, )[ QT?;
如: qeDXG
if @strWhere !='' 5O(U1
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begin Nwj M=GG
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere u4tv=+jh
end b@S~
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else 7{tU'`P>
begin W|Cs{rBc?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' j#~ S"t
end ov<vSc<u
我们可以直接写成 O7]kcA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere nx(jYXVT
2、收缩数据库 T[evh]koB
--重建索引 C#V_Gb
DBCC REINDEX }uwZS=pw
DBCC INDEXDEFRAG /PVx
--收缩数据和日志 Co,?<v=Ll
DBCC SHRINKDB -mP2}BNM
DBCC SHRINKFILE 5)Z:J
3、压缩数据库 b0sj0w /
dbcc shrinkdatabase(dbname) 7g5Pc_
4、转移数据库给新用户以已存在用户权限 "/G]M&
exec sp_change_users_login 'update_one','newname','oldname' l)e6*sDZ,
go 6?ky~CV
5、检查备份集 Z;z,dw
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' m
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6、修复数据库 27i-B\r
ALTER DATABASE [dvbbs] SET SINGLE_USER ^RE[5h6^q
GO L&KL]n
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK O=eU38n:5u
GO Kum" }ux
ALTER DATABASE [dvbbs] SET MULTI_USER ^M1jv(
GO *k,{[b
7、日志清除 t7yvd7
SET NOCOUNT ON LSR0yCU
DECLARE @LogicalFileName sysname, i= R%MH+
@MaxMinutes INT, K8/jfm
@NewSize INT !UR3`Xk
USE tablename -- 要操作的数据库名 Y(] W+k<
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 #)#J`s1R
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1LaJ
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@NewSize = 1 -- 你想设定的日志文件的大小(M) T_qM@/f
-- Setup / initialize ]4/C19Fe!
DECLARE @OriginalSize int SQ*%d.1
SELECT @OriginalSize = size c'XSs
FROM sysfiles m70AWG
WHERE name = @LogicalFileName .+mP#<mAg
SELECT 'Original Size of ' + db_name() + ' LOG is ' + odDVdVx0
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + guVuO
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' yf[1?{iVo
FROM sysfiles beBv|kI4
WHERE name = @LogicalFileName x:i,l:x
CREATE TABLE DummyTrans V["'eJA,,
(DummyColumn char (8000) not null) qu.AJ*
DECLARE @Counter INT, M+M ;@3
@StartTime DATETIME, uGn BlR$}
@TruncLog VARCHAR(255) XI:+EeM?
SELECT @StartTime = GETDATE(), JC`;hY
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' /eT9W[a
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 39m8iI%w[
EXEC (@TruncLog) xi=0kO
-- Wrap the log if necessary. vT MCZ+^g
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired OLWn0
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) L8f_^
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AND (@OriginalSize * 8 /1024) > @NewSize fu{v(^
BEGIN -- Outer loop. vM-kk:n7f
SELECT @Counter = 0 y<*\D_J
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) S?zP;
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BEGIN -- update [0 rH/{
INSERT DummyTrans VALUES ('Fill Log') O3?^P"C
DELETE DummyTrans #S]O|$&*
SELECT @Counter = @Counter + 1 *%\Xw*\0
END W6`_lGTj
EXEC (@TruncLog) mhM;`dl
END Y
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + M?Fv'YE
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Lp3pJE
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' W9{;HGWS
FROM sysfiles =jA.INin4
WHERE name = @LogicalFileName c(29JZ
DROP TABLE DummyTrans Zx`/88!x[
SET NOCOUNT OFF ~.6% %1?
8、说明:更改某个表 c}!`tBTm
exec sp_changeobjectowner 'tablename','dbo' c6 .j$6t
9、存储更改全部表 Zl>wWJ3y
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 'K}2 m
@OldOwner as NVARCHAR(128), 3DxgfP%n
@NewOwner as NVARCHAR(128) WZjR^6
AS oCLM'\
DECLARE @Name as NVARCHAR(128) <(~Wg{
DECLARE @Owner as NVARCHAR(128) vXZP>
DECLARE @OwnerName as NVARCHAR(128) ?%%vQ?
DECLARE curObject CURSOR FOR P8H2v_)X&
select 'Name' = name, SmRFxqtN
'Owner' = user_name(uid) unRFcjEa
from sysobjects w11L@t[5W8
where user_name(uid)=@OldOwner CKSs(-hkJ
order by name +3M1^:
OPEN curObject ?v-!`J>EF#
FETCH NEXT FROM curObject INTO @Name, @Owner {u0sbb(
WHILE(@@FETCH_STATUS=0) @\:@_}Z`_}
BEGIN S;/pm$?/
if @Owner=@OldOwner !]9qQ7+R%
begin tR4+]K
set @OwnerName = @OldOwner + '.' + rtrim(@Name) %{UW!/
exec sp_changeobjectowner @OwnerName, @NewOwner zo8&(XS
end *=]UWM~]
-- select @name,@NewOwner,@OldOwner [S-#}C?~
FETCH NEXT FROM curObject INTO @Name, @Owner ;\f0II3
END 9xK#(M
close curObject bdvpH DA
deallocate curObject AFeFH.G6Jr
GO o.Bbb=*rZ
10、SQL SERVER中直接循环写入数据 D><^ 7nr%
declare @i int 6-\'
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set @i=1 zGc]*R
while @i<30 kpy)kS
begin /!.]Y8yEH
insert into test (userid) values(@i) EP90E^v^
set @i=@i+1 Nx+5r p
end /Z~$`!J
小记存储过程中经常用到的本周,本月,本年函数 EMxMJ=
Dateadd(wk,datediff(wk,0,getdate()),-1) #)i+'L8
Dateadd(wk,datediff(wk,0,getdate()),6) '
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Dateadd(mm,datediff(mm,0,getdate()),0) EY.m,@{
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ,1.Td=lY$
Dateadd(yy,datediff(yy,0,getdate()),0) _;/+8=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) _PQk<QZ
上面的SQL代码只是一个时间段 1. <g C
Dateadd(wk,datediff(wk,0,getdate()),-1) &T ^bv*P
Dateadd(wk,datediff(wk,0,getdate()),6) % .ss
就是表示本周时间段. '|*e4n
下面的SQL的条件部分,就是查询时间段在本周范围内的: C[l5[DpH
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) J l{My^I5
而在存储过程中 e2>AL
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >5TXLOYZ
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) )4hA Fy6l