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。 ?d%+85
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一、基础 2f] :n
1、说明:创建数据库 EMU~gwPR
CREATE DATABASE database-name fz31di9$
2、说明:删除数据库 8)&yjY
drop database dbname
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3、说明:备份sql server 7=0uG
--- 创建 备份数据的 device FjRJSMwO,
USE master ;'!U/N;-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;Jr6
--- 开始 备份 fu}NH\{
BACKUP DATABASE pubs TO testBack ]|<PV5SY3.
4、说明:创建新表 8N4W}YBs
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) h`Vb#5ik
根据已有的表创建新表: .%+'Ts#ie
A:create table tab_new like tab_old (使用旧表创建新表) p%+ 0^]v1
B:create table tab_new as select col1,col2... from tab_old definition only E
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5、说明:删除新表 !p >a,8w
drop table tabname ^LaI{UDw%h
6、说明:增加一个列 "
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Alter table tabname add column col type H"WkZX
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。 !I-+wc{ss
7、说明:添加主键: Alter table tabname add primary key(col) 8jd<|nYnfc
说明:删除主键: Alter table tabname drop primary key(col) ( t#w@<
8、说明:创建索引:create [unique] index idxname on tabname(col....) J0a]Wz%
删除索引:drop index idxname TC?kuQI
注:索引是不可更改的,想更改必须删除重新建。 v Q[{<|K
9、说明:创建视图:create view viewname as select statement gP/[=:
删除视图:drop view viewname ~fI&F|
10、说明:几个简单的基本的sql语句 D$q"k"
选择:select * from table1 where 范围 3H%R`ha
插入:insert into table1(field1,field2) values(value1,value2) 0){%4
删除:delete from table1 where 范围 @;qC% +^
更新:update table1 set field1=value1 where 范围 {S%)GvrT
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! yT`[9u,
排序:select * from table1 order by field1,field2 [desc] \=Af AO@
总数:select count as totalcount from table1 '!Ps4ZTn_
求和:select sum(field1) as sumvalue from table1 `)\_
平均:select avg(field1) as avgvalue from table1 @g9j+DcU
最大:select max(field1) as maxvalue from table1 7J~6J.m
最小:select min(field1) as minvalue from table1 7Ro7/PT(
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11、说明:几个高级查询运算词 ehtiu!Vk
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A: UNION 运算符 F+*>q
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 +cvz
B: EXCEPT 运算符 hghtF
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 *U.$=4Az
C: INTERSECT 运算符 twz
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。 vY *p][$
注:使用运算词的几个查询结果行必须是一致的。 <]/`#Xgh
12、说明:使用外连接 B
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A、left outer join: Fly@"W4a
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。 8V_
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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 _Jk-nZgn
B:right outer join: SOb17:o3|
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。 vF;6Y(h>
C:full outer join: 75K~ebRr
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。 Vm'ReH
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二、提升 9r+ `j
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) e~$MIHBY]
法一:select * into b from a where 1<>1 $^I uE0.
法二:select top 0 * into b from a c[!e*n!y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) rr3NY$W
insert into b(a, b, c) select d,e,f from b; <3P?rcd,5K
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) ?XsL4HIx
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 P0RMdf
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \4K8*`$
4、说明:子查询(表名1:a 表名2:b) TMKemci
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) Mb\~WUWI
5、说明:显示文章、提交人和最后回复时间 *Zt)J8C
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b V?Lf&X?
6、说明:外连接查询(表名1:a 表名2:b) X^_,`H@
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 6]T02;b>/,
7、说明:在线视图查询(表名1:a ) eQcy'GA06
select * from (SELECT a,b,c FROM a) T where t.a > 1; -ud~'<k
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 o4Fh`?d}
select * from table1 where time between time1 and time2 9`dQ7z.8t
select a,b,c, from table1 where a not between 数值1 and 数值2 cIl^5eE^Pq
9、说明:in 的使用方法 _ H$Cm
select * from table1 where a [not] in ('值1','值2','值4','值6') 2s-f?WetbP
10、说明:两张关联表,删除主表中已经在副表中没有的信息 IAnY+=^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) akm) X0!-}
11、说明:四表联查问题: gD=s~DgN)
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... n+zXt?{u
12、说明:日程安排提前五分钟提醒 s]L`&fY]O
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 zZDG5_$n
13、说明:一条sql 语句搞定数据库分页 .w$v<y6C
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 rcxV ,<[B
14、说明:前10条记录 eX?o4>
select top 10 * form table1 where 范围 kt[#@M!}
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.) sN-5vYfC*
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) TQ=\l*R(A
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 T]Tz<w W(
(select a from tableA ) except (select a from tableB) except (select a from tableC) o"Ef>5N
17、说明:随机取出10条数据 DbPw)aCj
select top 10 * from tablename order by newid() ?e3q0Lg3|
18、说明:随机选择记录 L}>9@?;GW
select newid() 4DuZF
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19、说明:删除重复记录 En5Bsz!
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) m|24)%Vj;=
20、说明:列出数据库里所有的表名 t~5>PS
select name from sysobjects where type='U' &`@,mUi{Ac
21、说明:列出表里的所有的 !!2~lG<]
select name from syscolumns where id=object_id('TableName') +R2
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。 > %#J8
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 Zs+6Zd4f
显示结果: (d#?\
type vender pcs 5? c4aAn
电脑 A 1 jXZKR(L
电脑 A 1 HP]Xh~aP
光盘 B 2 UY}lJHp0
光盘 A 2 >/e#Z
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手机 B 3 ]lz,?izMR
手机 C 3 Ba`]Sm=
23、说明:初始化表table1 qf)]!wU9
TRUNCATE TABLE table1 C!qW:H
24、说明:选择从10到15的记录 xBB:b\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc WpTC,~-
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三、技巧 }[ AIE[
1、1=1,1=2的使用,在SQL语句组合时用的较多 EVb'x Zr
"where 1=1" 是表示选择全部 "where 1=2"全部不选, #\`6ZHW
如: +"'h?7'C
if @strWhere !=''
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begin c%xxsq2n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 4`Fbl]Q
end AqN(htGvx
else [W^6=7EO
begin Lg Bs<2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ?:U6MjlQ"{
end x!I7vs~~zW
我们可以直接写成 QQC0uta`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere \BJnJk!%
2、收缩数据库 l l&iMj]
--重建索引 y99G 3t
DBCC REINDEX PicO3m
DBCC INDEXDEFRAG nH[@EL
--收缩数据和日志 =FwFqjvl
DBCC SHRINKDB ig?]kZ
DBCC SHRINKFILE M.|hnGXN
3、压缩数据库 (%I`EAR
dbcc shrinkdatabase(dbname) ^]aDLjD
4、转移数据库给新用户以已存在用户权限 tM@TT@.t~
exec sp_change_users_login 'update_one','newname','oldname' 1%1-j
go .bpxSU%X
5、检查备份集 v{%2`_c
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' >aa-ix
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6、修复数据库 [k1N `K(M
ALTER DATABASE [dvbbs] SET SINGLE_USER >@rp]xx
GO .5ingB3%
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 8dL(cC
GO JNMZn/
ALTER DATABASE [dvbbs] SET MULTI_USER 0Q>Yoa
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GO *7-uQKp
7、日志清除 -Tz/ZOJ
SET NOCOUNT ON cT.1oaAM0
DECLARE @LogicalFileName sysname, T}4RlIZF
@MaxMinutes INT, (a)d7y.oo
@NewSize INT \ u5%+GA-:
USE tablename -- 要操作的数据库名 IClnh1=
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 6.K)uQgjmv
@MaxMinutes = 10, -- Limit on time allowed to wrap log. E-!`6
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2abWIw4
-- Setup / initialize S{
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DECLARE @OriginalSize int FQ O6w'
SELECT @OriginalSize = size zeR!Y yt!
FROM sysfiles Jh }3AoD
WHERE name = @LogicalFileName eqjl$QWPJS
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {){i
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Ng;E]2"
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' .;$/nz6vk
FROM sysfiles ]LP&v3
WHERE name = @LogicalFileName QF\NHV
CREATE TABLE DummyTrans rGq~e|.O3
(DummyColumn char (8000) not null) f+gyJ#R`
DECLARE @Counter INT, eR5swy&
@StartTime DATETIME, 2;6p2GNSh
@TruncLog VARCHAR(255) ^*Rr x
SELECT @StartTime = GETDATE(), 'MsxZqW"~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' \Dr@n^hk@[
DBCC SHRINKFILE (@LogicalFileName, @NewSize) |yQ3H)qB#
EXEC (@TruncLog) #x"pG
-- Wrap the log if necessary. c: #1Aym
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired c
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) tJg
AND (@OriginalSize * 8 /1024) > @NewSize IURi90Ir
BEGIN -- Outer loop. =DF7l<&km
SELECT @Counter = 0 [n66ZY#U]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) +KD~/}C%-
BEGIN -- update =u73AM}
INSERT DummyTrans VALUES ('Fill Log') rEZa%)XJ
DELETE DummyTrans j;<;?IW
SELECT @Counter = @Counter + 1 i mJ{wF
END oIbd+6>f
EXEC (@TruncLog) Y_f6y9?ZE
END 9h~>7VeZ)
SELECT 'Final Size of ' + db_name() + ' LOG is ' + :IS]|3wD
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + J}<k`af
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' KVqQOh'_T
FROM sysfiles "1`c^
WHERE name = @LogicalFileName KWhw@y-5j@
DROP TABLE DummyTrans +mV4Ty
SET NOCOUNT OFF ks'25tv}F
8、说明:更改某个表 SOeL@!_
exec sp_changeobjectowner 'tablename','dbo' Q{mls
9、存储更改全部表 .qF@
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ]y!|x_5c3
@OldOwner as NVARCHAR(128), m"@M~~bh
@NewOwner as NVARCHAR(128) /[_>U{~P#
AS $Ne#F+M9x
DECLARE @Name as NVARCHAR(128) `EV[uj&1S
DECLARE @Owner as NVARCHAR(128) k(hes3JV
DECLARE @OwnerName as NVARCHAR(128) ae#7*B
DECLARE curObject CURSOR FOR {f)",#
select 'Name' = name, {P-KU RQ
'Owner' = user_name(uid) }^P( p?~
from sysobjects -Z]?v3
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where user_name(uid)=@OldOwner sa*]q~a
order by name /koNcpJ
OPEN curObject !L-.bve!
FETCH NEXT FROM curObject INTO @Name, @Owner (q3(bH~T)
WHILE(@@FETCH_STATUS=0) f{5)yZ`J*
BEGIN j3z&0sc2(0
if @Owner=@OldOwner Z\O ,9
begin 4z[Z3|_V
set @OwnerName = @OldOwner + '.' + rtrim(@Name) T4qbyui{
exec sp_changeobjectowner @OwnerName, @NewOwner ugucq},[
end rN}{v}n
-- select @name,@NewOwner,@OldOwner D='/-3f!F]
FETCH NEXT FROM curObject INTO @Name, @Owner --.: eFE/
END Qh)@-r3
close curObject <@5#
deallocate curObject jlzqa7
GO Q)H Vh[4
10、SQL SERVER中直接循环写入数据 >
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declare @i int +<@7x16
set @i=1 JTl
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while @i<30 WB$Z<m:
begin 7P:0XML}
insert into test (userid) values(@i) z`5+BL,|ND
set @i=@i+1 MdZ7Yep
end #.a4}ya19
小记存储过程中经常用到的本周,本月,本年函数 HIi"zo=V
Dateadd(wk,datediff(wk,0,getdate()),-1) 4$d|}ajH
Dateadd(wk,datediff(wk,0,getdate()),6) $U"/.Mh\
Dateadd(mm,datediff(mm,0,getdate()),0) az0( 54M
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) yBht4"\Al
Dateadd(yy,datediff(yy,0,getdate()),0) >x&$lT{OY
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) w0tlF:Eg
上面的SQL代码只是一个时间段 9v<BO$
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Dateadd(wk,datediff(wk,0,getdate()),-1) qs 52)$
Dateadd(wk,datediff(wk,0,getdate()),6) g|e^}voRM
就是表示本周时间段. :#c? `>uV
下面的SQL的条件部分,就是查询时间段在本周范围内的: $*8c0.{U
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) #=Q/<r.~G
而在存储过程中 8p>%}LX/
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) -:cS}I
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ?GB($D=Y'&