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。 a3<:F2=~\
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一、基础 (_zlCHB
1、说明:创建数据库 HKXC=^}x'
CREATE DATABASE database-name L)bMO8JH~m
2、说明:删除数据库 <mE`<-$
drop database dbname v^b4WS+.:
3、说明:备份sql server lb.Q^TghU
--- 创建 备份数据的 device nf/?7~3?[
USE master WJOoDS!i
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %`yfi+e
--- 开始 备份 RkYn6
BACKUP DATABASE pubs TO testBack &\N>N7/1
4、说明:创建新表 b$7]cE
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) &bW,N
根据已有的表创建新表: (c(F1=K
A:create table tab_new like tab_old (使用旧表创建新表) b<00 %Z
B:create table tab_new as select col1,col2... from tab_old definition only x%=CEe?6
5、说明:删除新表 cK+TE8ao
drop table tabname RJ{$`d
6、说明:增加一个列 LigB!M
Alter table tabname add column col type b$,Hlh,^
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 v
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7、说明:添加主键: Alter table tabname add primary key(col) 8|i'~BFHs
说明:删除主键: Alter table tabname drop primary key(col) dtC@cK/,D
8、说明:创建索引:create [unique] index idxname on tabname(col....) ZwS:Te9-
删除索引:drop index idxname TVD~Ix
注:索引是不可更改的,想更改必须删除重新建。 U =.PL\
9、说明:创建视图:create view viewname as select statement zl@^[km{
删除视图:drop view viewname hy*{{f;
10、说明:几个简单的基本的sql语句 JpC'(N
选择:select * from table1 where 范围 ep"[;$Eb
插入:insert into table1(field1,field2) values(value1,value2) g#J aw|N
删除:delete from table1 where 范围 2!^=G=H/
更新:update table1 set field1=value1 where 范围 \)6glAtN
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] W%!(kN&d
总数:select count as totalcount from table1 N'v3
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求和:select sum(field1) as sumvalue from table1 !%G]~
平均:select avg(field1) as avgvalue from table1 _RbfyyaN
最大:select max(field1) as maxvalue from table1 MxsLrWxm
最小:select min(field1) as minvalue from table1 zqeQ
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11、说明:几个高级查询运算词 |Kd#pYt%O
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A: UNION 运算符 +F;2FD$
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。 <7^|@L
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B: EXCEPT 运算符 7rjl-FUA~
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。 [3m\~JtS
C: INTERSECT 运算符 #fuUAbU0X
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。 <Vhd4c
注:使用运算词的几个查询结果行必须是一致的。 {"ST
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12、说明:使用外连接 tIuM9D{P
A、left outer join: 9M96$i`P
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 }'oU/@yG
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5)#j }`6
B:right outer join: ?xj8a3F
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ?@b6(f
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C:full outer join: "V|Rq]_+%
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 H/D=$)3op
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二、提升 @>8(f#S%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l~r;Grd/5
法一:select * into b from a where 1<>1 Tv ``\<
法二:select top 0 * into b from a 9Dx~!(
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ~apt,hl
insert into b(a, b, c) select d,e,f from b; hG1$YE
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) =6sP`:
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 g NI1W@)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ]es|%j 2
4、说明:子查询(表名1:a 表名2:b) uN%Cc12
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) iuV4xyp
5、说明:显示文章、提交人和最后回复时间 SyL"Bmi
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b G@7^M}
6、说明:外连接查询(表名1:a 表名2:b) FQWjL>NB
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [c?0Q3F
7、说明:在线视图查询(表名1:a ) b<u\THy#
select * from (SELECT a,b,c FROM a) T where t.a > 1; tV++QC7@L
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 7Jb&~{DVk
select * from table1 where time between time1 and time2 QV[&2&&^<<
select a,b,c, from table1 where a not between 数值1 and 数值2 <-`bWz=+
9、说明:in 的使用方法 :|j[{;asY
select * from table1 where a [not] in ('值1','值2','值4','值6') q`e0%^U
10、说明:两张关联表,删除主表中已经在副表中没有的信息 e9p/y8gC
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) PF4[;ES'
11、说明:四表联查问题: uz3cho'
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... c^|8qvS$
12、说明:日程安排提前五分钟提醒 sUF$eVAT
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `gl?y;xC
13、说明:一条sql 语句搞定数据库分页 !{&r|6
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Q
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14、说明:前10条记录 +k=*AQt^8
select top 10 * form table1 where 范围 r6S
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) BFNO yv
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /qQx~doK
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 0hS&4nW
(select a from tableA ) except (select a from tableB) except (select a from tableC) wU%uO/sU9
17、说明:随机取出10条数据 ?"b __(3
select top 10 * from tablename order by newid() O!Ue0\1Kj0
18、说明:随机选择记录 Kj0)/Fjl+
select newid() T)tr"<F5NP
19、说明:删除重复记录 VmQ^F|
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 8mr fs%_
20、说明:列出数据库里所有的表名 9No6\{[M
select name from sysobjects where type='U' cJSNV*<
21、说明:列出表里的所有的 m#h`iW
select name from syscolumns where id=object_id('TableName') #7fOH
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 8z93ETv7`
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type pll5m7[
显示结果: X}B]5
type vender pcs Z@q1&}D!
电脑 A 1 .UxkTads
电脑 A 1 /: !sn-(
光盘 B 2 0Y`+L6&UX
光盘 A 2 o=VZ7]
手机 B 3 E.#JCO|(1
手机 C 3 n_sV>$f-u
23、说明:初始化表table1 ;zqxDl_
TRUNCATE TABLE table1 \1R*M
24、说明:选择从10到15的记录 ~,W|i
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc V xN!Ki=
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三、技巧 P'}EZ'
1、1=1,1=2的使用,在SQL语句组合时用的较多 ; 180ct4
"where 1=1" 是表示选择全部 "where 1=2"全部不选, FkaQVT
如: xqT} 9,
if @strWhere !='' x>i =
begin :4:U\k;QwA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere :CM2kh"Iu
end ;&b=>kPlZ
else TGpdl`k\T
begin s]vsD77&
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' B_!S\?}$
end iR4"I7J
我们可以直接写成 $hM9{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere fN`Prs A
2、收缩数据库 x}C$/ 7^
--重建索引 _J>Ik2EF
DBCC REINDEX ^(*eo e
DBCC INDEXDEFRAG Nj;(QhYZ
--收缩数据和日志 L#V e[
DBCC SHRINKDB Qz"@<qgQy
DBCC SHRINKFILE GyE5jh2
3、压缩数据库 Ud-c+, xX
dbcc shrinkdatabase(dbname) m7,"M~\pX
4、转移数据库给新用户以已存在用户权限 >wV2` 6
exec sp_change_users_login 'update_one','newname','oldname' ]{-ib:f~
go 5t-(MY
5、检查备份集 7r3EMX\#Qm
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' mqQ//$Y
6、修复数据库 !&8B8jHqA
ALTER DATABASE [dvbbs] SET SINGLE_USER 3k+46Wp
GO :JxuaM8
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK c"'JMq
GO U,9=&"e b
ALTER DATABASE [dvbbs] SET MULTI_USER r-}C !aF]
GO ]gb?3a}A
7、日志清除 F-?s8RD
SET NOCOUNT ON $8_b[~%2
DECLARE @LogicalFileName sysname, kEdAt5/U{
@MaxMinutes INT, c+TCC%AJQI
@NewSize INT |A
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USE tablename -- 要操作的数据库名 ,|R\ Z,s
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 _nW#Cl~
@MaxMinutes = 10, -- Limit on time allowed to wrap log. E7Pz~6
@NewSize = 1 -- 你想设定的日志文件的大小(M) A3e83g~L
-- Setup / initialize SQBe}FlktK
DECLARE @OriginalSize int H|!|fo-Tx
SELECT @OriginalSize = size z`@|v~i0`
FROM sysfiles I_h&35^t
WHERE name = @LogicalFileName l:VcV
SELECT 'Original Size of ' + db_name() + ' LOG is ' + (^Hpe5h&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + K<w$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' &qFy$`"
FROM sysfiles RS[QZOoW}
WHERE name = @LogicalFileName n#5%{e>
CREATE TABLE DummyTrans )1!*N)$
(DummyColumn char (8000) not null) }7|UA%xz
DECLARE @Counter INT, G8p6p6*
@StartTime DATETIME, 64-;| k4F
@TruncLog VARCHAR(255) |"EQyV
SELECT @StartTime = GETDATE(), B"I^hrQ
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ],ISWb
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0=KyupwXC
EXEC (@TruncLog) 8d"Ff
-- Wrap the log if necessary. <@2g.+9
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired EJ`"npU
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) iwnFCZVS
AND (@OriginalSize * 8 /1024) > @NewSize <MBpV^Y}
BEGIN -- Outer loop. ;JQ;LbEn
SELECT @Counter = 0 V17SJSC-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) pbePxOG
BEGIN -- update ;sn]Blpq
INSERT DummyTrans VALUES ('Fill Log') BO)Q$*G~JD
DELETE DummyTrans r5g:#mF"
SELECT @Counter = @Counter + 1 EG[Rda
END jpek=4E
EXEC (@TruncLog) f^?k?_~PN
END DNl'}K1W
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $UGX vCR
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + /V@9!
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' &;Jg2f%.
FROM sysfiles m<uBRI*I
WHERE name = @LogicalFileName &!5S'J%
DROP TABLE DummyTrans +GqUI~a
SET NOCOUNT OFF NvqIYW
8、说明:更改某个表 E1-BB
exec sp_changeobjectowner 'tablename','dbo' ~*Kk+w9H<
9、存储更改全部表 i917d@r( <
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 05gdVa,
@OldOwner as NVARCHAR(128), R9`37(c9+
@NewOwner as NVARCHAR(128) SV0h'd(b
AS ruQ1Cph
DECLARE @Name as NVARCHAR(128) zo~5(O@
DECLARE @Owner as NVARCHAR(128) >Kjl>bq
DECLARE @OwnerName as NVARCHAR(128) V 0M&D,
DECLARE curObject CURSOR FOR I=G-(L/&
select 'Name' = name, ;Wu6f"+Y#
'Owner' = user_name(uid) HXp$\%A)
from sysobjects ^\ocH|D
where user_name(uid)=@OldOwner qlgo#[i
order by name I@/+=
OPEN curObject hiQ #<
FETCH NEXT FROM curObject INTO @Name, @Owner $\A=J
WHILE(@@FETCH_STATUS=0) ]d]rV
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BEGIN -)LiL
if @Owner=@OldOwner Ods/1 KW
begin r(VznKSx
set @OwnerName = @OldOwner + '.' + rtrim(@Name) oDBv5
exec sp_changeobjectowner @OwnerName, @NewOwner s7>a
end b>Em~NMu_
-- select @name,@NewOwner,@OldOwner rCp'O\@S
FETCH NEXT FROM curObject INTO @Name, @Owner rZSD)I
END C_ 4(-OWq
close curObject #l?E2
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deallocate curObject J':x]_;
GO v%$c_'d
10、SQL SERVER中直接循环写入数据 bc}BQ|Q
declare @i int o;5 ns
set @i=1 QDdH5EfY
while @i<30 &b:SDl6
begin DP5}q"l
insert into test (userid) values(@i) 2{;~Bgd
set @i=@i+1 O.Xhi+
end >#Ue`)d`aY
小记存储过程中经常用到的本周,本月,本年函数 f5o##ia7:
Dateadd(wk,datediff(wk,0,getdate()),-1) nc/F@HCB
Dateadd(wk,datediff(wk,0,getdate()),6) +ko-oZ7V
Dateadd(mm,datediff(mm,0,getdate()),0) KqhE=2,
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) thK4@C|X4
Dateadd(yy,datediff(yy,0,getdate()),0) eRm 9LOp
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >,}SP;
上面的SQL代码只是一个时间段 \;bDDTM
Dateadd(wk,datediff(wk,0,getdate()),-1) :-)H
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Dateadd(wk,datediff(wk,0,getdate()),6) 6h9Hf$'
就是表示本周时间段. ]7DS>%mY(
下面的SQL的条件部分,就是查询时间段在本周范围内的: *1`q
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) cl1>S 3
而在存储过程中 ~A$y-Dt'
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) q'1
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) n>k 1D