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。 x;-D}#
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一、基础 ccp9nXv
1、说明:创建数据库 V0&7MY *
CREATE DATABASE database-name {XUSw8W'
2、说明:删除数据库 [?;L
drop database dbname m\bmBK"I
3、说明:备份sql server qPWf=s7!
--- 创建 备份数据的 device Fp[49
USE master ,dw\y/dn
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8G|?R#&
--- 开始 备份 wL^x9O|`p9
BACKUP DATABASE pubs TO testBack m}zXy\
4、说明:创建新表 pSIXv%1J
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) rO O10g
根据已有的表创建新表: JO&RuAq
A:create table tab_new like tab_old (使用旧表创建新表) NYs<`6P:Y
B:create table tab_new as select col1,col2... from tab_old definition only [KbLEMrPba
5、说明:删除新表 jO|`aUYTf
drop table tabname ?i\V^3S n$
6、说明:增加一个列 ko'V8r`V
Alter table tabname add column col type burSb:JF
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。 G\,B*$3
7、说明:添加主键: Alter table tabname add primary key(col) aG4 ^xOD
说明:删除主键: Alter table tabname drop primary key(col) $ndBT+i
8、说明:创建索引:create [unique] index idxname on tabname(col....) ,1lW`Krx
删除索引:drop index idxname hE'7M;
注:索引是不可更改的,想更改必须删除重新建。 9f5~hBlo
9、说明:创建视图:create view viewname as select statement
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删除视图:drop view viewname \yxGE+~P
10、说明:几个简单的基本的sql语句 t}pYSSTz
选择:select * from table1 where 范围 c'Z)uquvP
插入:insert into table1(field1,field2) values(value1,value2) 6"}F
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删除:delete from table1 where 范围 R%)F9P$o
更新:update table1 set field1=value1 where 范围 XpK
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! KbK!4
排序:select * from table1 order by field1,field2 [desc] B>\q!dX3
总数:select count as totalcount from table1 b].U/=Hs
求和:select sum(field1) as sumvalue from table1 eoQt87VCU
平均:select avg(field1) as avgvalue from table1 v4uQ0~k~X
最大:select max(field1) as maxvalue from table1 US-f<Wq
最小:select min(field1) as minvalue from table1 -~4kh]7%
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11、说明:几个高级查询运算词 sE|8a
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A: UNION 运算符 %(POC=b#[
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。 2.v`J=R
B: EXCEPT 运算符 xUa9>=JU{
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。 6Rq +=X
C: INTERSECT 运算符 bu\(KR$s
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。 )qFqf<:yc
注:使用运算词的几个查询结果行必须是一致的。 VAyAXN~
12、说明:使用外连接 Lk^bzW>f
A、left outer join: !/|B4Yv
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。 F*Yx1vj
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 8(S|=c R
B:right outer join: ybv< 1
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。 h2:TbQ
C:full outer join: P# 8lO%;
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。 .i` -t"
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二、提升 ;>X;cZMd
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) HyYJ"54
法一:select * into b from a where 1<>1 B/3xV:Gy
法二:select top 0 * into b from a G'nSnw
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) [<f9EeziB
insert into b(a, b, c) select d,e,f from b; P(C5@x(Z
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) Jiru~Vo+
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 5,|{|/
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. qk0cf~gz
4、说明:子查询(表名1:a 表名2:b) 7W&XcF
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) MBQ|*}+;
5、说明:显示文章、提交人和最后回复时间 9uX15a
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ]}]+aB
6、说明:外连接查询(表名1:a 表名2:b) [?2?7>D8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c L`rrT
7、说明:在线视图查询(表名1:a ) -ni@+Dy
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7v.O Lp
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 $V/Ke
select * from table1 where time between time1 and time2 ZHoYnp-~z
select a,b,c, from table1 where a not between 数值1 and 数值2 , BZ(-M
9、说明:in 的使用方法 7s}F`fjKP
select * from table1 where a [not] in ('值1','值2','值4','值6') CWd
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 "Z dI~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) !l6ht{
11、说明:四表联查问题: PVmePgF
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 ..... 6_tl_O7
12、说明:日程安排提前五分钟提醒 r.=.,R
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 >+:cTQ|q
13、说明:一条sql 语句搞定数据库分页 \3F)M`g
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 ;2sP3!*
14、说明:前10条记录 Sj8fo^K50
select top 10 * form table1 where 范围 r,L`@A=v
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.) |0_5iFAB|
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) {e., $'#
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 l)EtK&er(}
(select a from tableA ) except (select a from tableB) except (select a from tableC) 4>Nig.#
17、说明:随机取出10条数据 : 'pK
select top 10 * from tablename order by newid() W(.svJUgb.
18、说明:随机选择记录 /}CAd
select newid() *ck'vV'@
19、说明:删除重复记录 rK'O 85)eU
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) '3E25BsL
20、说明:列出数据库里所有的表名 %8P6l D
select name from sysobjects where type='U' t0^)Q$
21、说明:列出表里的所有的 =">0\#
select name from syscolumns where id=object_id('TableName') }me`(zp
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。 ;H?tcb*
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 CXi:?6OG
显示结果: N)KN!!
type vender pcs y'^b{q@
电脑 A 1 ]XYD2fR2qA
电脑 A 1 ~C?)-
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光盘 B 2 Enp;-wG:-
光盘 A 2 O}6*9Xy
手机 B 3 EKmn@S-&P
手机 C 3 A
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23、说明:初始化表table1 .j"@7#tW
TRUNCATE TABLE table1 Ve40H6Ox
24、说明:选择从10到15的记录 :G5O_T$
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc =^)$my\C:
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三、技巧 shVEAT'`
1、1=1,1=2的使用,在SQL语句组合时用的较多 ?H8dyQ5"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, t
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如: X 0LC:0+
if @strWhere !='' >.hDt9@4
begin C!Fi &~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere !H6X%hlk
end ._&SS,I5VZ
else z|$9%uz"
begin /9?yw!
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 7(<r4{1?
end H9WXp&
我们可以直接写成 6DC+8I<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 0sF|Y%N
2、收缩数据库 z<9Llew^e
--重建索引 <2OXXQ1
DBCC REINDEX Na+h+wD.D
DBCC INDEXDEFRAG
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--收缩数据和日志 0*AXd=)"*
DBCC SHRINKDB Z,8t!Y
DBCC SHRINKFILE NT9| ``^Z
3、压缩数据库 hOuHTo^
dbcc shrinkdatabase(dbname) 9H+Q/Q*-a
4、转移数据库给新用户以已存在用户权限 f#gV>.P;h\
exec sp_change_users_login 'update_one','newname','oldname' n`T4P$pt
go D4~]:@v~n
5、检查备份集 8wn{W_5a
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;f}
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6、修复数据库 v'r)d-T
ALTER DATABASE [dvbbs] SET SINGLE_USER 4Ofkagg
GO D?4bp'0 3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK F#.ph?W
GO \[ 4y
ALTER DATABASE [dvbbs] SET MULTI_USER wGxH
GO gq="&
7、日志清除 al7D3J
SET NOCOUNT ON 4^:$|\?]
DECLARE @LogicalFileName sysname, K'f2S
@MaxMinutes INT, q)J5tBfJ
@NewSize INT -x|!?u5F
USE tablename -- 要操作的数据库名 be?Bf^O>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^$[iLX
@MaxMinutes = 10, -- Limit on time allowed to wrap log. F&
@NewSize = 1 -- 你想设定的日志文件的大小(M) ]kF1~kXBe
-- Setup / initialize '"'RC O
DECLARE @OriginalSize int Zx7aae_{
SELECT @OriginalSize = size j-ob7(v)*]
FROM sysfiles nC)"% Sa
WHERE name = @LogicalFileName 8]rObT9>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 0?O_]SD
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + DhD##5a
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' g1(5QWb
FROM sysfiles kO$n0y5e
WHERE name = @LogicalFileName {CNJlr@z
CREATE TABLE DummyTrans <qEBF`XP =
(DummyColumn char (8000) not null) m!=5Q S3Z
DECLARE @Counter INT, ^dE[ ;
@StartTime DATETIME, )g}G{9M^
@TruncLog VARCHAR(255) WZh_z^rwn
SELECT @StartTime = GETDATE(), QS1lg
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' !YZKa-
DBCC SHRINKFILE (@LogicalFileName, @NewSize) }}k*i0
EXEC (@TruncLog) v5U'ky:
-- Wrap the log if necessary. 9}Ge@a<j
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired O\)Kg2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) $1Zr.ERL|(
AND (@OriginalSize * 8 /1024) > @NewSize +;M 5Sp
BEGIN -- Outer loop. ~$hR:I1
SELECT @Counter = 0 2 )3oX
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) v>N*f~n
BEGIN -- update {-f%g-@L6|
INSERT DummyTrans VALUES ('Fill Log') #^R@EZ
DELETE DummyTrans 23 #JmR
SELECT @Counter = @Counter + 1 XODp[+xEEt
END w0vsdM;G
EXEC (@TruncLog) dDD5OnWmJ
END Rw FA
SELECT 'Final Size of ' + db_name() + ' LOG is ' + .rnT'""i<5
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + UBk:B
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' xq=!1>
FROM sysfiles %~8f0B|im
WHERE name = @LogicalFileName l-S0Gn/'X
DROP TABLE DummyTrans 9)o@d`*
SET NOCOUNT OFF Fw
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8、说明:更改某个表 )jg*u}u
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exec sp_changeobjectowner 'tablename','dbo'
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9、存储更改全部表 n&zEYCSI
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch `!(%Rk
@OldOwner as NVARCHAR(128), =tP^vgfQ
@NewOwner as NVARCHAR(128) 5X>~39(r
AS _Hfpizm
DECLARE @Name as NVARCHAR(128) X%kJ3{
DECLARE @Owner as NVARCHAR(128) #g0N/
DECLARE @OwnerName as NVARCHAR(128) 11kyrv
DECLARE curObject CURSOR FOR _\Z'Yl
select 'Name' = name, +v:]#1
'Owner' = user_name(uid) @!O(%0
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from sysobjects r;*
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where user_name(uid)=@OldOwner '
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order by name 4VwMl)8ic
OPEN curObject (
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FETCH NEXT FROM curObject INTO @Name, @Owner ?%Tx%
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WHILE(@@FETCH_STATUS=0) V2M4g
BEGIN HW,v"
if @Owner=@OldOwner &zJ*afi)
begin $`ptSR
set @OwnerName = @OldOwner + '.' + rtrim(@Name) jm@M"b'{
exec sp_changeobjectowner @OwnerName, @NewOwner +`>E_+Mp
end =Y6W
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-- select @name,@NewOwner,@OldOwner MSeg7/ MF
FETCH NEXT FROM curObject INTO @Name, @Owner tcsb]/my
END dv3u<X M~
close curObject A#19&}
deallocate curObject LL)t)
GO ^Jq('@
10、SQL SERVER中直接循环写入数据 "` cP V){]
declare @i int !G0Mg; ,
set @i=1 8>6<GdGL<n
while @i<30 GEh( pJ
begin Zv=pS
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insert into test (userid) values(@i) S.1>bs2
set @i=@i+1 %6 GM[1__
end {=mGXd`x?l
小记存储过程中经常用到的本周,本月,本年函数 q*`
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Dateadd(wk,datediff(wk,0,getdate()),-1) ~ss6yQ$
Dateadd(wk,datediff(wk,0,getdate()),6) JS%LJ_J
Dateadd(mm,datediff(mm,0,getdate()),0) \4G9YK-N>
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) II.:k.D`
Dateadd(yy,datediff(yy,0,getdate()),0) 9X;*GC;d
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) aGi`(|shW
上面的SQL代码只是一个时间段 Tq?Ai_
Dateadd(wk,datediff(wk,0,getdate()),-1) E?P>s T3B
Dateadd(wk,datediff(wk,0,getdate()),6) 3Wv^{|^
就是表示本周时间段. =RRv&
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下面的SQL的条件部分,就是查询时间段在本周范围内的: h4|}BGO
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 4m91XD
而在存储过程中 (B\
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) BSgT
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) oe
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