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。 `pYE[y+
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一、基础 k+\7B}7F
1、说明:创建数据库 1URsHV!xcM
CREATE DATABASE database-name kPJ~X0Fr{t
2、说明:删除数据库 @3 "DBJ
drop database dbname MVAc8d S
3、说明:备份sql server Ihef$,
--- 创建 备份数据的 device y h-9u
USE master P1QB`&8F
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' A_Gp&acs$
--- 开始 备份 7ukDS]
BACKUP DATABASE pubs TO testBack h544dNo&
4、说明:创建新表 ~~dfpW _"
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }}s)
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根据已有的表创建新表: 6QptKXu7
A:create table tab_new like tab_old (使用旧表创建新表) AzX(~Qc
B:create table tab_new as select col1,col2... from tab_old definition only rxkBg0Z`a
5、说明:删除新表 `w=!o.1
drop table tabname o}R|tOe
6、说明:增加一个列 Ap,q
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Alter table tabname add column col type },3R%?89%
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。 HjPH
7、说明:添加主键: Alter table tabname add primary key(col) nK:`e9ES
说明:删除主键: Alter table tabname drop primary key(col) .Bijc G
8、说明:创建索引:create [unique] index idxname on tabname(col....) "b;k.Fx
删除索引:drop index idxname Y;PDZbK3
注:索引是不可更改的,想更改必须删除重新建。 s.ey!ew
9、说明:创建视图:create view viewname as select statement -(ER4#
删除视图:drop view viewname n(# c`t*
10、说明:几个简单的基本的sql语句 mZ &]
选择:select * from table1 where 范围 P#9-bYNU
插入:insert into table1(field1,field2) values(value1,value2) $YR{f[+L
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删除:delete from table1 where 范围 +{bh
更新:update table1 set field1=value1 where 范围 L%4tw5*N
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! A'(k
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排序:select * from table1 order by field1,field2 [desc] t9n'!
总数:select count as totalcount from table1 '|+=B u
求和:select sum(field1) as sumvalue from table1 _4S7wOq5
平均:select avg(field1) as avgvalue from table1 @@xF#3
最大:select max(field1) as maxvalue from table1 <m9JXO:5
最小:select min(field1) as minvalue from table1 'jwTGT5x
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11、说明:几个高级查询运算词 Is~yVB02
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A: UNION 运算符 0c{Gr 0[>
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 4O9tx_<JG
B: EXCEPT 运算符 %k~C-+
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 A`
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C: INTERSECT 运算符 >EyvdX#v
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 K T"h74@
注:使用运算词的几个查询结果行必须是一致的。 lp3(&p<:
12、说明:使用外连接 NdaM9a#TZ
A、left outer join: ;%lJD"yF
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 )Ep@$Gv|S
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 1Z=;Uy\
B:right outer join: -U&098}<K
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。 LjX&',
C:full outer join: ',<{X(#(
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。 VN1#8{
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二、提升 6!i(
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 4j2~"K
法一:select * into b from a where 1<>1 DWHOSXA4
法二:select top 0 * into b from a &4a~6
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) *(>F'>F1"
insert into b(a, b, c) select d,e,f from b; q
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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) IhtmD@H}
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 8kKRx
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. )[F46?$vrk
4、说明:子查询(表名1:a 表名2:b) \r)_-
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) mJU>f-l
5、说明:显示文章、提交人和最后回复时间 EVby 9!
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b U]1>?,Nk'3
6、说明:外连接查询(表名1:a 表名2:b) .oW~:mY
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c q>wa#1X)
7、说明:在线视图查询(表名1:a ) d{(s-
select * from (SELECT a,b,c FROM a) T where t.a > 1; $u(M 4(}
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 x`b~ZSNJ%
select * from table1 where time between time1 and time2 ]a&x'
select a,b,c, from table1 where a not between 数值1 and 数值2 %`8KG(F^
9、说明:in 的使用方法 C{U[w^X
select * from table1 where a [not] in ('值1','值2','值4','值6') E0WrpGZ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 bUEt0wRR
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7l4InR]
11、说明:四表联查问题: woC
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... aH~x7N6!
12、说明:日程安排提前五分钟提醒 q|de*~@-P
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 e%5'(V-y,
13、说明:一条sql 语句搞定数据库分页 I3F6-gH
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 h[M6.
14、说明:前10条记录 Q)7L^
select top 10 * form table1 where 范围 ZKiL-^dob
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) kM}ic(K
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) `:B
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ]y$V/Ij=qK
(select a from tableA ) except (select a from tableB) except (select a from tableC) h|Teh-@A5
17、说明:随机取出10条数据 pfT`W T
select top 10 * from tablename order by newid() `i_L?C7
18、说明:随机选择记录 A$$R_3ne
select newid() %$!R] B)
19、说明:删除重复记录 JXD?a.vy^q
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) }(O D<
20、说明:列出数据库里所有的表名 ~ L i%
select name from sysobjects where type='U' ft.}$8vIT
21、说明:列出表里的所有的 W6!4Qyn
select name from syscolumns where id=object_id('TableName') V"D<)VVA
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 H8Z Z@@ qm
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type v;NZ"1=_
显示结果: /^es0$Co.
type vender pcs /d]V{I~6
电脑 A 1 5;i!PuL
电脑 A 1 S
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光盘 B 2 ytcG6WN3
光盘 A 2 }G:uzud10
手机 B 3 Yqz[sz5+m
手机 C 3 @{$Cv"6769
23、说明:初始化表table1 ZE3ysLkm
TRUNCATE TABLE table1 >stVsFdV)
24、说明:选择从10到15的记录 VTgbJ{?
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc c#4L*$ViF
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三、技巧 r{N{!"G
1、1=1,1=2的使用,在SQL语句组合时用的较多 =='{[[J
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ff5
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如: ^xkppN2
if @strWhere !='' U(&nh?
begin pGcx
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ^*UfCoj9Z
end QGCdeE$K
else \eSk7C
begin CTrs\G
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Ev|{~U
end kI[O {<kQ
我们可以直接写成 p31rhe
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere V]PhXVJ
2、收缩数据库 L)nVpqm
--重建索引 ^@5ui;JV
DBCC REINDEX ,5+X%~'
DBCC INDEXDEFRAG i7!mMO8]
--收缩数据和日志 bZlLivi
DBCC SHRINKDB gW pT:tX-
DBCC SHRINKFILE dK(%u9v
3、压缩数据库 n#L2cv~Aj"
dbcc shrinkdatabase(dbname) ,m'#>d&zO
4、转移数据库给新用户以已存在用户权限 HtXBaIl\
exec sp_change_users_login 'update_one','newname','oldname' }ok
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go F@(}=w^(A
5、检查备份集 2WECQl=r
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' a=T7w;\h
6、修复数据库 {hq ;7
ALTER DATABASE [dvbbs] SET SINGLE_USER ~Z/ `W`
GO xW;[}t-QS
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 4Z
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GO 8\V>6^3CD$
ALTER DATABASE [dvbbs] SET MULTI_USER y<x_v )k-
GO yc4f\0B/
7、日志清除 Ac(irPrD
SET NOCOUNT ON r~!%w(N|M
DECLARE @LogicalFileName sysname, `L[32B9
@MaxMinutes INT, KA{DN!
@NewSize INT }b\q<sNE{
USE tablename -- 要操作的数据库名 <l
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1YD.jU^;HD
@MaxMinutes = 10, -- Limit on time allowed to wrap log. nu%Nt"~[%
@NewSize = 1 -- 你想设定的日志文件的大小(M) U)=Z&($T
-- Setup / initialize ,) jB<`
DECLARE @OriginalSize int E6-(q!"A
SELECT @OriginalSize = size K]*ERAfM%m
FROM sysfiles Y},GZ ^zqy
WHERE name = @LogicalFileName LmdV@gR
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 3rdxXmx
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + y\|\9Q%D
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' kQ'xs%Fw
FROM sysfiles v6Wf7)d/1
WHERE name = @LogicalFileName QAnfxt6
CREATE TABLE DummyTrans UT7lj wT
(DummyColumn char (8000) not null) uqeWdj*Y
DECLARE @Counter INT, Wv/5#_
@StartTime DATETIME, r9'H7J
@TruncLog VARCHAR(255) R$m?&1K
SELECT @StartTime = GETDATE(), WWD@rn sVf
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6}lEeMRW
DBCC SHRINKFILE (@LogicalFileName, @NewSize) yf^gU*
EXEC (@TruncLog) H0NyxG<
-- Wrap the log if necessary. mBkQ
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired PCnJ2
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) l8lR5<
AND (@OriginalSize * 8 /1024) > @NewSize >mSl~.I2
BEGIN -- Outer loop. qc"/T16M]
SELECT @Counter = 0 neH"ks5
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) P>Rqy
BEGIN -- update uQ+$Hzx X
INSERT DummyTrans VALUES ('Fill Log') .[85<"C
DELETE DummyTrans U*h)nc
SELECT @Counter = @Counter + 1 -7VV5W
END ?|YQtY
EXEC (@TruncLog) Pg C]@Q%
END ZP/=R<<
SELECT 'Final Size of ' + db_name() + ' LOG is ' + dg8\(G
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + &c ~)z\$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' r_RTtS#
FROM sysfiles SP1oBR"3
WHERE name = @LogicalFileName ToM*tXj
DROP TABLE DummyTrans wf$ JuHPt
SET NOCOUNT OFF L(S.
8、说明:更改某个表 L KR,CPz
exec sp_changeobjectowner 'tablename','dbo' d>psqmQ
9、存储更改全部表 nE%qm -
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch %=eD)p7l-
@OldOwner as NVARCHAR(128), q2i~<;Z)9
@NewOwner as NVARCHAR(128) v]S8!wU
AS Hf|:A(vCx
DECLARE @Name as NVARCHAR(128) ;KN@v5`p
DECLARE @Owner as NVARCHAR(128) Bn:sN_N
DECLARE @OwnerName as NVARCHAR(128) kO"aE~
DECLARE curObject CURSOR FOR ?,>y`Qf*|
select 'Name' = name, 7s3<}
'Owner' = user_name(uid) VH65=9z
from sysobjects 6E4 L4Vb
where user_name(uid)=@OldOwner DL{a8t1L
order by name `"4EE}eQc
OPEN curObject n8,/olqwW
FETCH NEXT FROM curObject INTO @Name, @Owner xc3Q7u!|
WHILE(@@FETCH_STATUS=0) @S):a`J
BEGIN .p_$]
if @Owner=@OldOwner (Cd`~*5
begin FM];+d0
set @OwnerName = @OldOwner + '.' + rtrim(@Name) FgaBwd^W
exec sp_changeobjectowner @OwnerName, @NewOwner 1t'\!
end h 42?^mV4?
-- select @name,@NewOwner,@OldOwner !I&Sy]G
FETCH NEXT FROM curObject INTO @Name, @Owner sBL^NDqa2
END aH~"hB^e
close curObject ;oE4,
deallocate curObject U"Oq85vY
GO f#mpd]e+6
10、SQL SERVER中直接循环写入数据 &Y$rVBgQ
declare @i int dGjvSK<1@
set @i=1 \3/'#
while @i<30 ysPW<
begin ,55`s#;
insert into test (userid) values(@i) 3iTjM>+>
set @i=@i+1 [XK"$C]jHJ
end K.~U%v}
小记存储过程中经常用到的本周,本月,本年函数 5N/;'ySAE_
Dateadd(wk,datediff(wk,0,getdate()),-1) kEh# 0
Dateadd(wk,datediff(wk,0,getdate()),6) @hPbD?)M
Dateadd(mm,datediff(mm,0,getdate()),0) <Jz>e}*)
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) jL<.?HE
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) X(9Ff=0.~
上面的SQL代码只是一个时间段 KNhH4K2iP8
Dateadd(wk,datediff(wk,0,getdate()),-1) DGnswN%n1
Dateadd(wk,datediff(wk,0,getdate()),6) lLv0lf
就是表示本周时间段. xB#E&}Ho
下面的SQL的条件部分,就是查询时间段在本周范围内的: cAS5&T<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) cjk5><}`H7
而在存储过程中 8:bNFgJD
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) +FR"Gt$g
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) XijQ)}'C3