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。 {T$9?`h~M
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一、基础 i+ ?^8#
1、说明:创建数据库 1hY{k{+o
CREATE DATABASE database-name oq
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2、说明:删除数据库 EH J.T~X
drop database dbname S6DKREO
3、说明:备份sql server yLvDMPj
--- 创建 备份数据的 device D0-3eV-
USE master 2`K=Hby
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 5{X<y#vAC0
--- 开始 备份 N)X3XTY
BACKUP DATABASE pubs TO testBack vH@ds
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4、说明:创建新表 2*& ^v
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) vm8eZG|
根据已有的表创建新表: ?(1y
A:create table tab_new like tab_old (使用旧表创建新表) rH Lm\3
B:create table tab_new as select col1,col2... from tab_old definition only &jJL"gq"
5、说明:删除新表 6Pl<'3&
drop table tabname F0TB<1
6、说明:增加一个列 AO4U}?
Alter table tabname add column col type ,?%Zc$\LW
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。 b4 6~?*
7、说明:添加主键: Alter table tabname add primary key(col) `Y$4 H,8L
说明:删除主键: Alter table tabname drop primary key(col) *~e?TfG
8、说明:创建索引:create [unique] index idxname on tabname(col....) eF$x 1|
删除索引:drop index idxname & '`g#N
注:索引是不可更改的,想更改必须删除重新建。 0Th&iA4
9、说明:创建视图:create view viewname as select statement BL}\D;+t
删除视图:drop view viewname zR:L!S
10、说明:几个简单的基本的sql语句 S9y}
选择:select * from table1 where 范围 K($Npuu]
插入:insert into table1(field1,field2) values(value1,value2) @Cyvf5|bL
删除:delete from table1 where 范围 &U#|uc!+
更新:update table1 set field1=value1 where 范围 $Ds2>G4c
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! B~ GbF*j
排序:select * from table1 order by field1,field2 [desc] ! n@KU!&k
总数:select count as totalcount from table1 N=}A Z{$
求和:select sum(field1) as sumvalue from table1 83_h J
平均:select avg(field1) as avgvalue from table1 013x8!i
最大:select max(field1) as maxvalue from table1 #=A)XlZMd
最小:select min(field1) as minvalue from table1 )7Wf@@R'F
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11、说明:几个高级查询运算词 jV1.Yz(`
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A: UNION 运算符 |/{=ww8|
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。 VlsnL8DV
B: EXCEPT 运算符 f.$af4
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 .M%}X7
C: INTERSECT 运算符 qo bc<-
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 *.t7G
注:使用运算词的几个查询结果行必须是一致的。 .W!i7
12、说明:使用外连接 (hbyEQhF
A、left outer join: fIU#M]Xx
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 }S-O&Z
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c _]H&,</
B:right outer join: c-5)QF) z
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 JK5gQ3C[
C:full outer join: n Dxz~8
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 !_)[/q"
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二、提升 iqWQ!r^
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ggR.4&<
法一:select * into b from a where 1<>1 gjD Ho$
法二:select top 0 * into b from a xi}skA
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) W^l-Y%a/o
insert into b(a, b, c) select d,e,f from b; 2E'UZ
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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) !%c\N8<>GD
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 )jP1or
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Yc?*dUV
4、说明:子查询(表名1:a 表名2:b) e(t\g^X
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) E:nF$#<'N
5、说明:显示文章、提交人和最后回复时间 NC(~l
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b zQd
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6、说明:外连接查询(表名1:a 表名2:b) 64tvP^kp
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c k5pN
7、说明:在线视图查询(表名1:a ) %*}(}~
select * from (SELECT a,b,c FROM a) T where t.a > 1; 2\{zmc}G-0
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 uKHxe~
select * from table1 where time between time1 and time2 DB}eA N/
select a,b,c, from table1 where a not between 数值1 and 数值2 4H&+dRI"
9、说明:in 的使用方法 Rima;9.Y0
select * from table1 where a [not] in ('值1','值2','值4','值6') AoxA+.O
10、说明:两张关联表,删除主表中已经在副表中没有的信息 U>N1Od4vTO
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) m9rp8r*e
11、说明:四表联查问题: T_4/C2
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ,k3FRes3
12、说明:日程安排提前五分钟提醒 ISvpQ 3{)s
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0 kW,I
13、说明:一条sql 语句搞定数据库分页 ]}Yl7/gM1}
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 "4{r6[dn
14、说明:前10条记录 g}c~ :p
select top 10 * form table1 where 范围 aPL+=5 8r
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) KbeC"mi
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 8$}<, c(
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'A%:f<
(select a from tableA ) except (select a from tableB) except (select a from tableC) C?eH]hkZ3
17、说明:随机取出10条数据 <Q3c[ Y
select top 10 * from tablename order by newid() . $vK&k
18、说明:随机选择记录 7qS)c}Q\
select newid() Y}wyw8g/
19、说明:删除重复记录 oUlVI*~ND
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) A*BeR0(
20、说明:列出数据库里所有的表名 Cw&KVw*
select name from sysobjects where type='U' H qx-;F~0
21、说明:列出表里的所有的 xJ.M;SF4
select name from syscolumns where id=object_id('TableName') nBYZ}L 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。 0</);g}
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 UkFC~17P
显示结果: ,z=LY5_z)
type vender pcs Qo|\-y-#
电脑 A 1 tKXIk9e
电脑 A 1 *s3/!K
光盘 B 2 j0q&&9/Jj
光盘 A 2 4j^
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手机 B 3 {+>-7
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手机 C 3 r9?Mw06Wc5
23、说明:初始化表table1 JB<t6+"rD
TRUNCATE TABLE table1 Jln:`!#fDf
24、说明:选择从10到15的记录 j#4kY R{
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc o ^uA">GH
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三、技巧 x]j W<A
1、1=1,1=2的使用,在SQL语句组合时用的较多 xyXa .
"where 1=1" 是表示选择全部 "where 1=2"全部不选, MF'JeM;H
如: '~ 47)fN
if @strWhere !='' E2-\]?\F(
begin &UFZS94@r
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~wdGd+ez
end cU
else {_*yGK48n
begin )t%b838l%
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' \Vk:93OH21
end n+R7D.<q!!
我们可以直接写成 .e-#yET
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |DwZ{(R"W
2、收缩数据库 :Hbv)tS\3w
--重建索引 uXiN~j &Be
DBCC REINDEX #O&8A
DBCC INDEXDEFRAG Pg{J{gn
--收缩数据和日志 m]&SN z=
DBCC SHRINKDB t6t!t*jO
DBCC SHRINKFILE 7d\QB(~
3、压缩数据库 #\ErY3k 6&
dbcc shrinkdatabase(dbname) lU]nd[x
4、转移数据库给新用户以已存在用户权限 7t3!)a|lI
exec sp_change_users_login 'update_one','newname','oldname' +ZX{>:vo
go # f\rt
5、检查备份集 8 zb/xP>
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' n=q76W\
6、修复数据库 0n'_{\yz
ALTER DATABASE [dvbbs] SET SINGLE_USER cZ3v=ke^
GO _yT Ed"$
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK !<F3d`a
GO ?V=CB,^
ALTER DATABASE [dvbbs] SET MULTI_USER Iu6
GO W%w~ah|/]
7、日志清除 0*v2y*2V
SET NOCOUNT ON Gq P5Kx+=
DECLARE @LogicalFileName sysname, $:^td/p J
@MaxMinutes INT, Ho]su?
@NewSize INT ;AG()NjOO:
USE tablename -- 要操作的数据库名 19] E 5'AI
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ee=D1 qNu;
@MaxMinutes = 10, -- Limit on time allowed to wrap log. +w~oH =
@NewSize = 1 -- 你想设定的日志文件的大小(M) @(lh%@hO
-- Setup / initialize l+b~KU7~l
DECLARE @OriginalSize int |vC~HJpuv'
SELECT @OriginalSize = size {.]7!ISl5
FROM sysfiles 2KZneS`
WHERE name = @LogicalFileName ;F Eqe49
SELECT 'Original Size of ' + db_name() + ' LOG is ' + [fyLV`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + K)P%;X
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Tj- s4x
FROM sysfiles O".=r}
WHERE name = @LogicalFileName QsW/X0YBv
CREATE TABLE DummyTrans 1
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(DummyColumn char (8000) not null) "Y.y:Vv;
DECLARE @Counter INT, p
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@StartTime DATETIME, R|Q?KCI&
@TruncLog VARCHAR(255) 8?C5L8)
SELECT @StartTime = GETDATE(), (-co.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' #LNED)Vg
DBCC SHRINKFILE (@LogicalFileName, @NewSize) _VXN#@y
EXEC (@TruncLog) }GIt!PG
-- Wrap the log if necessary. Yr|4Fl~U
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired !Z6{9sKR=]
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) o !7va"
AND (@OriginalSize * 8 /1024) > @NewSize <oeIcN7d
BEGIN -- Outer loop. v-Sd*( 6
SELECT @Counter = 0 6w7 7YTJ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 3$JoDL(Z
BEGIN -- update @%SQFu@FJ
INSERT DummyTrans VALUES ('Fill Log') ~QVH<`sn
DELETE DummyTrans 6H|S;K+
SELECT @Counter = @Counter + 1 ;n},"&
END sR8"3b<qA
EXEC (@TruncLog) 3gf1ownC
END | f##5fB
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ?@8[e9lLD
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + :v 4]D4\o
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' IRbfNq^:
FROM sysfiles WF"k[2
WHERE name = @LogicalFileName DV{=n C
DROP TABLE DummyTrans M^I(OuRMeI
SET NOCOUNT OFF hv+zGID7
8、说明:更改某个表 ;wD)hNLAvR
exec sp_changeobjectowner 'tablename','dbo' 1YMh1+1
9、存储更改全部表 2T`!v
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ~)'k 9?0
@OldOwner as NVARCHAR(128), Q@H V- (A
@NewOwner as NVARCHAR(128) Y\tui+?J
AS c`Wa^(
DECLARE @Name as NVARCHAR(128) -{A<.a3P}=
DECLARE @Owner as NVARCHAR(128) u= yOu^={
DECLARE @OwnerName as NVARCHAR(128) QS j]ZA
DECLARE curObject CURSOR FOR xezcAwW
select 'Name' = name, %>s|j'{
'Owner' = user_name(uid) azU"G(6y?+
from sysobjects rLT!To
where user_name(uid)=@OldOwner O
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order by name =w^M{W.w
OPEN curObject K+iP6B
FETCH NEXT FROM curObject INTO @Name, @Owner E)3NxmM#
WHILE(@@FETCH_STATUS=0) )}ROLe
BEGIN (iGTACoF
if @Owner=@OldOwner ~{gqsuCCL
begin q'11^V!0
set @OwnerName = @OldOwner + '.' + rtrim(@Name) B1Oq!k
exec sp_changeobjectowner @OwnerName, @NewOwner \[nut;
end =Runf
+}
-- select @name,@NewOwner,@OldOwner |&jXp%4T
FETCH NEXT FROM curObject INTO @Name, @Owner YoE3<[KD(
END 9ll~~zF99|
close curObject rQ9'bCSr%
deallocate curObject P>6{&(
GO k_R"CKd
10、SQL SERVER中直接循环写入数据 `,0}ZzaV&
declare @i int tI{_y
set @i=1 @lt#Nz
while @i<30 1nOCQ\$l
begin bN88ua}k{
insert into test (userid) values(@i) |Ds=)S"
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set @i=@i+1 O1kl70,`R
end BPHW}F]X
小记存储过程中经常用到的本周,本月,本年函数 ,=N.FS
Dateadd(wk,datediff(wk,0,getdate()),-1) {_dvx*M
Dateadd(wk,datediff(wk,0,getdate()),6) i@CxI<1'
Dateadd(mm,datediff(mm,0,getdate()),0) L.WljNo
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 39jG8zr=Z[
Dateadd(yy,datediff(yy,0,getdate()),0) vcd\GN*4f
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) M@ZI\
上面的SQL代码只是一个时间段 KG5>]_GH
Dateadd(wk,datediff(wk,0,getdate()),-1) ]s748+
Dateadd(wk,datediff(wk,0,getdate()),6) lHIM}~#;nd
就是表示本周时间段. 9k=3u;$v
下面的SQL的条件部分,就是查询时间段在本周范围内的: 0|b>I!_"g
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~v"L!=~G;a
而在存储过程中 1i] ^{;]
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) FCn_^l)EA
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Tb-F]lg$