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。 :\P@c(c{^C
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一、基础 i7-~"g
1、说明:创建数据库 'z5jnI
CREATE DATABASE database-name pT->qQ3;
2、说明:删除数据库 =~h b&
drop database dbname G~8BND[."
3、说明:备份sql server )gdLb}
--- 创建 备份数据的 device zUL,~u
USE master QF/_?Tm4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' zP%s] >hH
--- 开始 备份 gAWi&
BACKUP DATABASE pubs TO testBack XJ\R'?j
4、说明:创建新表 DOJydYds
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) dhob]8b
根据已有的表创建新表: Au'y(KB
A:create table tab_new like tab_old (使用旧表创建新表) "H[K3
B:create table tab_new as select col1,col2... from tab_old definition only '~&W'='b;
5、说明:删除新表 ?-<lIFFh
drop table tabname }6%XiP|
6、说明:增加一个列 (T#$0RFq
Alter table tabname add column col type I?}jf?!oM
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 H]R/=OYBUh
7、说明:添加主键: Alter table tabname add primary key(col) I{cH$jt<
说明:删除主键: Alter table tabname drop primary key(col) iVn4eLK^v
8、说明:创建索引:create [unique] index idxname on tabname(col....) MSQ^ovph
删除索引:drop index idxname l; _IH|A
注:索引是不可更改的,想更改必须删除重新建。 ]5"k%v|
9、说明:创建视图:create view viewname as select statement E+O{^C=
删除视图:drop view viewname =0d|F
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10、说明:几个简单的基本的sql语句 N9_* {HOy
选择:select * from table1 where 范围 NSz}
插入:insert into table1(field1,field2) values(value1,value2) ]##aAh-P4&
删除:delete from table1 where 范围 '_G\_h}5
更新:update table1 set field1=value1 where 范围 RH;ulAD6(~
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4-.K<-T%D
排序:select * from table1 order by field1,field2 [desc] f"FFgQMkv
总数:select count as totalcount from table1 6P{^j
求和:select sum(field1) as sumvalue from table1 kP%hgZ
平均:select avg(field1) as avgvalue from table1 gUru=p
最大:select max(field1) as maxvalue from table1 />S^`KSTM
最小:select min(field1) as minvalue from table1 z)^|.
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11、说明:几个高级查询运算词 ?z9!=A%<V~
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A: UNION 运算符 1p.c6[9-
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。 JI-i7P
B: EXCEPT 运算符 $CE dJ+0z
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。 @vlP)"
C: INTERSECT 运算符 y8~OkdlN#
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。 Xk4wU$1F
注:使用运算词的几个查询结果行必须是一致的。 $v@$C4
12、说明:使用外连接 3
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A、left outer join: wN!\$i@E:
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。 ;0 B1P|7zK
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 vdq=F|&
B:right outer join: jU&m*0nL
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。 $yASWz
C:full outer join: jhm3:;Z
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 )*BZo>"
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二、提升 e3 v^j$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) `yv?PlKL
法一:select * into b from a where 1<>1 {6ZSf[Y6B
法二:select top 0 * into b from a t<8)h8eW
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 3<^Up1CaZ
insert into b(a, b, c) select d,e,f from b; eC!=4_lx)
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) dS6 $
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Y#9W]78He
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. R2Tt6
4、说明:子查询(表名1:a 表名2:b) :01d9|#
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)
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5、说明:显示文章、提交人和最后回复时间 r/sSkF F
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b nc;eNB
6、说明:外连接查询(表名1:a 表名2:b) C1D:Xi-
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c y47N(;vy
7、说明:在线视图查询(表名1:a ) \V$qAfP)
select * from (SELECT a,b,c FROM a) T where t.a > 1; \AwkK3
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 n2mO-ZXud
select * from table1 where time between time1 and time2 H4y9\
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select a,b,c, from table1 where a not between 数值1 and 数值2 }%u#TwZ
9、说明:in 的使用方法 D -tRy~}
select * from table1 where a [not] in ('值1','值2','值4','值6') K+}0:W=P
10、说明:两张关联表,删除主表中已经在副表中没有的信息 V~dhTdQ5}
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) [q?RJmB]
11、说明:四表联查问题: c* ueI5i
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... * 1;4&/93o
12、说明:日程安排提前五分钟提醒 ^`kwSC
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 b-<0\@`Z#
13、说明:一条sql 语句搞定数据库分页 _;k<=ns(=
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 c7XBZ%D
14、说明:前10条记录 Lu}jk
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select top 10 * form table1 where 范围 H'k}/<%Q
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Y$ jX
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) <Z%=lwtX
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 @}4aF|
(select a from tableA ) except (select a from tableB) except (select a from tableC) (mIjG)4t
17、说明:随机取出10条数据 d1cp=RbC
select top 10 * from tablename order by newid() Cy[G7A%
18、说明:随机选择记录 %V>%AP
select newid() MZV$YD^S
19、说明:删除重复记录 T[SK>z
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) *S}@DoXS
20、说明:列出数据库里所有的表名 { U;yW)
select name from sysobjects where type='U' to?! qxn
21、说明:列出表里的所有的 >/A]C$?3
select name from syscolumns where id=object_id('TableName') wyy
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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。 HV~Fe!J_
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 xh2r?K@k>
显示结果: ,ucRQ&P
type vender pcs BEOPZ[Q|c
电脑 A 1 Or? )Nlg6x
电脑 A 1 UH MJ(.Wa-
光盘 B 2 N6._Jb
光盘 A 2 EnWv9I<
手机 B 3 q\@Zf}
手机 C 3 UQu6JkbLL
23、说明:初始化表table1 MKfK9>a
TRUNCATE TABLE table1 8'*x88+
24、说明:选择从10到15的记录 1D'r;`z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc gF,=rT1:>r
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三、技巧 k;^$Pd?t
1、1=1,1=2的使用,在SQL语句组合时用的较多 c]{}|2u
"where 1=1" 是表示选择全部 "where 1=2"全部不选, GURiW42
如: ~]-n%J$q
if @strWhere !='' M G$+Blw>
begin iE'' >Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere T_S3_-|{==
end v*!N}1+J
else K) }1;
begin WAxNQfEe
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' X<,QSTP
end }[akj8U
我们可以直接写成 #KiJ{w'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere W_}j~[&
2、收缩数据库 I(*3n"
--重建索引 I,hw0e
DBCC REINDEX E4% -*n
DBCC INDEXDEFRAG 5f7id7SI
--收缩数据和日志 ^t})T*hM0
DBCC SHRINKDB Oo
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DBCC SHRINKFILE d3c.lD)L9
3、压缩数据库 Tow=B
dbcc shrinkdatabase(dbname) Rt?CE jy
4、转移数据库给新用户以已存在用户权限 Pg8.RvmQ
exec sp_change_users_login 'update_one','newname','oldname' 4;AF\De
go $bG*f*w
5、检查备份集 Br!;Ac&N
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' HS<Jp44
6、修复数据库 )Jjp^U3Ub
ALTER DATABASE [dvbbs] SET SINGLE_USER ?SNacN@r
GO 8H4NNj Oy
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK +ALrHFG
GO @/:4beh
ALTER DATABASE [dvbbs] SET MULTI_USER 4NID:<
GO %4nf(|8n
7、日志清除 )9nW`d+
SET NOCOUNT ON I#2$CSJ
DECLARE @LogicalFileName sysname, qj;i03 +@
@MaxMinutes INT, =_`q;Tu=
@NewSize INT ]`)5 Qe4
USE tablename -- 要操作的数据库名 &?R/6"J
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 V| V9.
@MaxMinutes = 10, -- Limit on time allowed to wrap log. rC!O}(4t%$
@NewSize = 1 -- 你想设定的日志文件的大小(M) VFf;|PHS
-- Setup / initialize Q2 !GWz$
DECLARE @OriginalSize int f5*qlQJFz\
SELECT @OriginalSize = size ZR\N~.
FROM sysfiles C7dq=(p&
WHERE name = @LogicalFileName Q#3}AO
SELECT 'Original Size of ' + db_name() + ' LOG is ' + @4y?XL(n
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,cNe-KJk
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ',R%Q0Q
FROM sysfiles |J!mM<*K
WHERE name = @LogicalFileName $sY'=S
CREATE TABLE DummyTrans h\[@J rDa
(DummyColumn char (8000) not null) `o{ Z;-OF
DECLARE @Counter INT, -|FHv+
@StartTime DATETIME, >UCg3uFj
@TruncLog VARCHAR(255) TnN
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SELECT @StartTime = GETDATE(), ]R""L<K%HF
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' P*!`AWn
DBCC SHRINKFILE (@LogicalFileName, @NewSize) JH\:9B+:L
EXEC (@TruncLog) Hl}lxK,]
-- Wrap the log if necessary. :f[ w
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired eE'P)^KV
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) LL
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AND (@OriginalSize * 8 /1024) > @NewSize p/(Z2N"
BEGIN -- Outer loop. #$Zx ].[lc
SELECT @Counter = 0 p? L%'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (e'8>Pv
BEGIN -- update RTh=x.
INSERT DummyTrans VALUES ('Fill Log') O8 .iP+
DELETE DummyTrans v's1&%sM
SELECT @Counter = @Counter + 1 D;P=\i>9-
END BSMb(EnqX
EXEC (@TruncLog) Led\S;pl
END '!^7 *@z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2L&c91=wE
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + lW?}Ts~'
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' q7lC}'2fu
FROM sysfiles k( Sda>-
WHERE name = @LogicalFileName e#/&A5#Ya
DROP TABLE DummyTrans QwX81*nx
SET NOCOUNT OFF Zy+ERaF|]
8、说明:更改某个表 EK4%4<"
exec sp_changeobjectowner 'tablename','dbo' {3
9、存储更改全部表 S%MDQTM
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch HVus\s\&y%
@OldOwner as NVARCHAR(128), MU$tX
@NewOwner as NVARCHAR(128) u~OlJ1V
AS T!,5dt8L
DECLARE @Name as NVARCHAR(128) 6agq^wI
DECLARE @Owner as NVARCHAR(128) }OEL] 5
DECLARE @OwnerName as NVARCHAR(128) i!2k f
DECLARE curObject CURSOR FOR |aLK_]!
select 'Name' = name, ow \EL
'Owner' = user_name(uid) e$s&B!qJ
from sysobjects XnP?hw%
where user_name(uid)=@OldOwner Z5v_- +K
order by name 8p 4[:M@
OPEN curObject 1*p6UR&
FETCH NEXT FROM curObject INTO @Name, @Owner =
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WHILE(@@FETCH_STATUS=0) >fYcr#i0[
BEGIN (Huvo9
if @Owner=@OldOwner ]<<,{IQ
begin v'?Smd1v
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) 9KX% O-'
exec sp_changeobjectowner @OwnerName, @NewOwner B(M-;F
end `F/R:!v
-- select @name,@NewOwner,@OldOwner E "=4(
FETCH NEXT FROM curObject INTO @Name, @Owner +#,J`fV%
END Z5TA4Q+Q
close curObject Rf0so
deallocate curObject we_CF*zj
GO ]AA|BeL?|
10、SQL SERVER中直接循环写入数据 d2eXN3"
declare @i int XB!qPh.
set @i=1 C"kfxpCi
while @i<30 6qDt6uB
begin %!t9)pNc
insert into test (userid) values(@i) r5xm7- `c
set @i=@i+1 X`_tm3HC
end 5[)5K?%
小记存储过程中经常用到的本周,本月,本年函数 8|@) #:
Dateadd(wk,datediff(wk,0,getdate()),-1) jv.tg,c _6
Dateadd(wk,datediff(wk,0,getdate()),6)
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Dateadd(mm,datediff(mm,0,getdate()),0) SLEOcOAmD
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) B0yJ9U= Fj
Dateadd(yy,datediff(yy,0,getdate()),0)
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) |?J57(
上面的SQL代码只是一个时间段 <B>qEa_I
Dateadd(wk,datediff(wk,0,getdate()),-1) >bWpj8Kv
Dateadd(wk,datediff(wk,0,getdate()),6) FNUs
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就是表示本周时间段. %P ~;>4i,
下面的SQL的条件部分,就是查询时间段在本周范围内的: |aenQA#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) JYWoQ[ZO#>
而在存储过程中 Q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) W#U|;@"
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9]+zZP_#