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。 i4',d#
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一、基础 !9w;2Z]uum
1、说明:创建数据库 f&z@J,_=
CREATE DATABASE database-name 6}Iu~|5
2、说明:删除数据库 .Mn+Bd4f
drop database dbname eM3-S=R?<g
3、说明:备份sql server jbDap i<
--- 创建 备份数据的 device qHAZ)Tz
USE master 51,RbADB
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' l6YToYzE2
--- 开始 备份 fV 6$YCf
BACKUP DATABASE pubs TO testBack f3g#(1
4、说明:创建新表 C4Tn
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) p "J^
根据已有的表创建新表: T7wy{;
A:create table tab_new like tab_old (使用旧表创建新表) Lc0U-!{G
B:create table tab_new as select col1,col2... from tab_old definition only [<2#C#P:6
5、说明:删除新表 ,-4SVj8$P
drop table tabname ?PMF]ah
6、说明:增加一个列 CY"iP,nHl
Alter table tabname add column col type dn"&j1@KY
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。 5BztOYn,
7、说明:添加主键: Alter table tabname add primary key(col) 0n'~wz"wB
说明:删除主键: Alter table tabname drop primary key(col) TA
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8、说明:创建索引:create [unique] index idxname on tabname(col....) <c,/+
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删除索引:drop index idxname .e^AS~4pl
注:索引是不可更改的,想更改必须删除重新建。 HQpw2bdy
9、说明:创建视图:create view viewname as select statement u:6PAVW?
删除视图:drop view viewname yMJY6$Ct
10、说明:几个简单的基本的sql语句 k|ol+
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选择:select * from table1 where 范围 cz2guUu
插入:insert into table1(field1,field2) values(value1,value2) Ql%0%naq1
删除:delete from table1 where 范围 8 |@WuD
更新:update table1 set field1=value1 where 范围 ftL>oOz[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *KDT0 ;/s
排序:select * from table1 order by field1,field2 [desc] "agc*o~!F
总数:select count as totalcount from table1 j.'Rm%@u
求和:select sum(field1) as sumvalue from table1 J?Ed^B-
平均:select avg(field1) as avgvalue from table1 :9_N
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最大:select max(field1) as maxvalue from table1 _fVC\18T
最小:select min(field1) as minvalue from table1 e)(m0m\
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11、说明:几个高级查询运算词 ?gq',FFDq
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A: UNION 运算符 FqvMi:F
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 oicj3xkw?
B: EXCEPT 运算符 +[=yLE#P%
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ;yc|=I^
C: INTERSECT 运算符 g^CAT1}
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 S$=e %c
注:使用运算词的几个查询结果行必须是一致的。 !<ae~#]3P
12、说明:使用外连接 Ab"mX0n
A、left outer join: DgJG: D{
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。 B\/"$"
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 P3due|4M
B:right outer join: #4?(A[]>H
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。 ndsu}:my
C:full outer join: |5ifgSZ
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。 f;Iaf#V_
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二、提升 M"E ]r=1
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) w""5T|
法一:select * into b from a where 1<>1 HjX!a29Wf
法二:select top 0 * into b from a *\UxdL 22
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;[)t*yAh
insert into b(a, b, c) select d,e,f from b; liYR8 D
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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) 5M.KF;P
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 97$1na3gq
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. #WOb&h
4、说明:子查询(表名1:a 表名2:b) 7c:5Ey
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) jq4'=L$4
5、说明:显示文章、提交人和最后回复时间 4z~%gt74O]
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b &HPzm6.3
6、说明:外连接查询(表名1:a 表名2:b) efK)6T^p
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c @.4e^Km
7、说明:在线视图查询(表名1:a ) L4)@lmd3
select * from (SELECT a,b,c FROM a) T where t.a > 1; 5]Wkk~a
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 =,*4:TU
select * from table1 where time between time1 and time2 }]qx "
select a,b,c, from table1 where a not between 数值1 and 数值2 5`ma#_zk|f
9、说明:in 的使用方法 xJ;DkPh
select * from table1 where a [not] in ('值1','值2','值4','值6') d/Sx+1
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 [vIHYp
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) g{`r WKj
11、说明:四表联查问题: Jb~nu
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... m[@7!.0=
12、说明:日程安排提前五分钟提醒 \"E-z.wW=
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 P]Hcg|&
13、说明:一条sql 语句搞定数据库分页 STC'j1U
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 `OY_v=}
14、说明:前10条记录 jY]hMQ/H
select top 10 * form table1 where 范围 F-=W7 D:[c
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) [5v[Zqud
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =Yxu {]G
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ]t69a4&,#9
(select a from tableA ) except (select a from tableB) except (select a from tableC) -H@Gyw
17、说明:随机取出10条数据 s}~'o!}W
select top 10 * from tablename order by newid() YWfw%p?n"
18、说明:随机选择记录 (HHVup1f
select newid() nUZ+N)*
19、说明:删除重复记录 `.0QY<;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) WSdTP$?
20、说明:列出数据库里所有的表名 Vx]{<}(gr
select name from sysobjects where type='U' }tH$/-qnJE
21、说明:列出表里的所有的 J,8Wo6
select name from syscolumns where id=object_id('TableName') $X.X_
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 %N"9'g>
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type p'2ZDd=v
显示结果: u1?1x
type vender pcs Ib)>M`J
电脑 A 1 Ha~g8R&
电脑 A 1 oSb,)k@
光盘 B 2 fbbk;Rq.'3
光盘 A 2 x)X=sX.
手机 B 3 eBD7 g-
手机 C 3 oQrkd:
23、说明:初始化表table1 T~nm Eap
TRUNCATE TABLE table1 ZaCUc Px
24、说明:选择从10到15的记录 *):x K;o
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc cuJ%;q=;
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三、技巧 _084GK9{W
1、1=1,1=2的使用,在SQL语句组合时用的较多 [Z3B~c
"where 1=1" 是表示选择全部 "where 1=2"全部不选, YN\!I
如: rb+&]
if @strWhere !='' MP Ma
begin e ;4y5i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere *wml
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end =[O;/~J%:
else axTvA(k9
begin k+^-;=u6<
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' t3TnqA
end a0Y/,S*K
我们可以直接写成 ! H)D@,@ &
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere !6t
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2、收缩数据库 /f!CX|U
--重建索引 K-$gTV
DBCC REINDEX l\=M'D
DBCC INDEXDEFRAG LB<,(dyh
--收缩数据和日志 l
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DBCC SHRINKDB c}nXMA^^
DBCC SHRINKFILE L0_qHLY
3、压缩数据库 EwSE;R -
dbcc shrinkdatabase(dbname) c\.8hd=<
4、转移数据库给新用户以已存在用户权限 mdu5aL
exec sp_change_users_login 'update_one','newname','oldname' mVYLI!n}0#
go t]Ey~-Rx
5、检查备份集 5feCA ,v7
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' R3]Ra&h6N)
6、修复数据库 m6P!#=a:l<
ALTER DATABASE [dvbbs] SET SINGLE_USER &n%
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GO `(|jm$Q
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Bc{#ia
GO ?#F}mOVAa
ALTER DATABASE [dvbbs] SET MULTI_USER %N!2 _uk5
GO wo;`D
7、日志清除 ,+0>p
SET NOCOUNT ON `P&L. m]|
DECLARE @LogicalFileName sysname, W/PZD (
@MaxMinutes INT, sR`WV6!9
@NewSize INT Qh )QdW4
USE tablename -- 要操作的数据库名 p[*NekE6-
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 +tz^ &(
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 0&1!9-(d
@NewSize = 1 -- 你想设定的日志文件的大小(M) lNSB "S
-- Setup / initialize hP4*S^l
DECLARE @OriginalSize int G]fl33_}l
SELECT @OriginalSize = size lx<]v^
FROM sysfiles X@u-n_
WHERE name = @LogicalFileName $I%75IZ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Ku{DdiTg>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + L]o
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ?XVJ$nzW
FROM sysfiles gB!K{ Io'
WHERE name = @LogicalFileName C LhD[/Fo
CREATE TABLE DummyTrans UE4zmIq
(DummyColumn char (8000) not null) ;C8'7
DECLARE @Counter INT, *)c,~R^
@StartTime DATETIME, g->cgExj
@TruncLog VARCHAR(255) P=K+!3ZXo
SELECT @StartTime = GETDATE(), vb{+yEa
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' _
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) ,Yg<Z1
EXEC (@TruncLog) U@$Kp>X
-- Wrap the log if necessary. gk+$CyjJ
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Az2HlKF"L
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) s9 '*Vm
AND (@OriginalSize * 8 /1024) > @NewSize Cc:m~e6r
BEGIN -- Outer loop. n237%LH[
SELECT @Counter = 0 CErkmod{}e
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) f!}c0nb
BEGIN -- update :%Dw3IrOM
INSERT DummyTrans VALUES ('Fill Log') h(hb?f@1:
DELETE DummyTrans `;L0ax
SELECT @Counter = @Counter + 1 W?m?r.K?
END DXAA[hUjF
EXEC (@TruncLog) :U`8s#
END 6g@@V=mf
SELECT 'Final Size of ' + db_name() + ' LOG is ' + [{F8+a^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + oLcOp.8h[
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' s1XW}Dw
FROM sysfiles /i+8b(x
WHERE name = @LogicalFileName "1rZwFI0l
DROP TABLE DummyTrans JHN35a+
SET NOCOUNT OFF Pm]6E[zC
8、说明:更改某个表 z<~gv"
exec sp_changeobjectowner 'tablename','dbo' Xidt\08s
9、存储更改全部表 6Cut[*lj^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch I(r ^q"
@OldOwner as NVARCHAR(128), [o)P
@NewOwner as NVARCHAR(128) J;Az0[qMR
AS #2c-@),
DECLARE @Name as NVARCHAR(128) 5-|fp(Ww_W
DECLARE @Owner as NVARCHAR(128) Qci<cVgP
DECLARE @OwnerName as NVARCHAR(128) FJ3Xeos4|
DECLARE curObject CURSOR FOR $l:?(&u
select 'Name' = name, |y@TI
'Owner' = user_name(uid) 5fS89?/?
from sysobjects xUE 9%qO
where user_name(uid)=@OldOwner Ue|]M36
order by name ]@bo; .
OPEN curObject jcF/5u5e
FETCH NEXT FROM curObject INTO @Name, @Owner wU.K+4-k
WHILE(@@FETCH_STATUS=0) 4NxtU/5-sU
BEGIN vkan+~H
if @Owner=@OldOwner fSdv%$;Hc
begin b'fj
set @OwnerName = @OldOwner + '.' + rtrim(@Name) Y418k
exec sp_changeobjectowner @OwnerName, @NewOwner eRllF `*
end ,R$n I*mf_
-- select @name,@NewOwner,@OldOwner F|X-|Co
FETCH NEXT FROM curObject INTO @Name, @Owner }5^j08
END hQrO8T?2
close curObject Fs7/3
deallocate curObject 5EDM?G
GO :0pxacD"!
10、SQL SERVER中直接循环写入数据 ;pdW7
declare @i int emb~l{K $
set @i=1 2E/#fX9!4
while @i<30 $~4ZuV%
begin Nko;I?Fn
insert into test (userid) values(@i) 8}m]XO
set @i=@i+1 GE=#8-@g~p
end ^I9x@t
小记存储过程中经常用到的本周,本月,本年函数 P-ma~g>I
Dateadd(wk,datediff(wk,0,getdate()),-1) :NHh`@0F
Dateadd(wk,datediff(wk,0,getdate()),6) LRD71*/
Dateadd(mm,datediff(mm,0,getdate()),0) ( B$;'U<
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) XiI@Px?FL
Dateadd(yy,datediff(yy,0,getdate()),0) zEJ|;oL
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) BvpGP
上面的SQL代码只是一个时间段 ymybj
Dateadd(wk,datediff(wk,0,getdate()),-1) e-f_#!bW
Dateadd(wk,datediff(wk,0,getdate()),6) Gk2\B]{
就是表示本周时间段. 0Ph,E
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4O[T:9mn0
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) &O(z|-&| x
而在存储过程中 b#|M-DmT
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 0o[p<<c*
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) z7F~;IB*u