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。 rv^@, 8vq
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一、基础 ;!mzyb*
1、说明:创建数据库 nn:.nU|I
CREATE DATABASE database-name Ng2@z<>.
2、说明:删除数据库 ll<Xz((o
drop database dbname 0y" $MC v
3、说明:备份sql server rq/yD,I,
--- 创建 备份数据的 device :bu/^mW[
USE master kHghPn?8]
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' jrlVvzZ
--- 开始 备份 rb2S7k0{
BACKUP DATABASE pubs TO testBack GmeQ`;9,
4、说明:创建新表 0d"[l@UU0
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) u~M
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根据已有的表创建新表: 1#V_Z^OL
A:create table tab_new like tab_old (使用旧表创建新表) hYT0l$Ng
B:create table tab_new as select col1,col2... from tab_old definition only Sz)' ogl
5、说明:删除新表 w;[NH/A^a
drop table tabname w(*vj
6、说明:增加一个列 l6T-}h:=
Alter table tabname add column col type dUeN*Nq&(,
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。 Ja7R2-0ii#
7、说明:添加主键: Alter table tabname add primary key(col) xjuN-
说明:删除主键: Alter table tabname drop primary key(col) U3ADsdn
8、说明:创建索引:create [unique] index idxname on tabname(col....) lk^Ol&6
删除索引:drop index idxname ??-[eB.
注:索引是不可更改的,想更改必须删除重新建。 ?>D+ge
9、说明:创建视图:create view viewname as select statement fnjPSts0
删除视图:drop view viewname P_dCR
10、说明:几个简单的基本的sql语句 V%7WUq
选择:select * from table1 where 范围 ]^. _z
插入:insert into table1(field1,field2) values(value1,value2) ~9a<0Mc?
删除:delete from table1 where 范围 q 6:dy
更新:update table1 set field1=value1 where 范围 T6y\|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 5Md=-,'J!
排序:select * from table1 order by field1,field2 [desc] [i21FX
总数:select count as totalcount from table1 GfxZ'VIn
求和:select sum(field1) as sumvalue from table1 G}9Jg
平均:select avg(field1) as avgvalue from table1 AP n| \
最大:select max(field1) as maxvalue from table1 p,5i)nEFj
最小:select min(field1) as minvalue from table1 |sJ[0z
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11、说明:几个高级查询运算词 O40?{v'
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A: UNION 运算符 \#2Z)Kz
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。 <prk8jSWV
B: EXCEPT 运算符 YquI $PV _
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 *<$*"p
C: INTERSECT 运算符 (+w*[qHe
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。 bQzZy5,
注:使用运算词的几个查询结果行必须是一致的。 2prU
12、说明:使用外连接 EKYY6S2
A、left outer join: afCW(zHp
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。 %8RrRW
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 JinUV6cr
B:right outer join: oM
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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。 A6
C:full outer join: paA(C|%{
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。 KaLzg5is
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二、提升 U45e2~1!O
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) #>a\>iKQ2q
法一:select * into b from a where 1<>1 I
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法二:select top 0 * into b from a CQc+#nRe
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \,'m</o~,
insert into b(a, b, c) select d,e,f from b; u%GEqruo[
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) ,5P0S0*{
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 vRYQ{:
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ` _6C{<O
4、说明:子查询(表名1:a 表名2:b) Gf%~{@7=u
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) (=FRmdeYl1
5、说明:显示文章、提交人和最后回复时间 N_LM/of|D
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b DcS+_>a\{l
6、说明:外连接查询(表名1:a 表名2:b) h7*J9[$
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "-E\[@/
7、说明:在线视图查询(表名1:a ) m=1N>cq
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select * from (SELECT a,b,c FROM a) T where t.a > 1; !K#qe Y}
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 ]HbY
select * from table1 where time between time1 and time2 #]-SJWf3
select a,b,c, from table1 where a not between 数值1 and 数值2 b3P+H r
9、说明:in 的使用方法 +Z,;,5'5G
select * from table1 where a [not] in ('值1','值2','值4','值6') %J}xg^+f
10、说明:两张关联表,删除主表中已经在副表中没有的信息 -D<< kra
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) H[T?\Lq
11、说明:四表联查问题: 5G}?fSQ>
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 ..... 8u"U1
12、说明:日程安排提前五分钟提醒 XjB W9a
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 gZVc 5u<
13、说明:一条sql 语句搞定数据库分页 y1z4ik)Sd@
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 "BAK !N$9
14、说明:前10条记录 "mo?*
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select top 10 * form table1 where 范围 _OYasJUMG
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) \-E^lIVF
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) -$\y_?}
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 b\f
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(select a from tableA ) except (select a from tableB) except (select a from tableC) eNh39er
17、说明:随机取出10条数据 4>YR{
select top 10 * from tablename order by newid() Fk7?xc
18、说明:随机选择记录 0J*??g-n
select newid() 'JtBZFq
19、说明:删除重复记录 `K"L /I9
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) `6;?9NI
20、说明:列出数据库里所有的表名 qfF~D0}
select name from sysobjects where type='U' &/Z
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21、说明:列出表里的所有的 A.F%Ycq
select name from syscolumns where id=object_id('TableName') 7jrt7[{
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。 je\Ph5 "
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 S
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显示结果: LG0;#3YwH
type vender pcs q~Hn-5H4Q
电脑 A 1 xh-o}8*n"
电脑 A 1 %X]jaX7
光盘 B 2 'd0~!w
光盘 A 2 Ng&%o
手机 B 3 .N;=\C*
手机 C 3 Z9E\,Ly
23、说明:初始化表table1 1y&\5kB
TRUNCATE TABLE table1 q_lKKzA
24、说明:选择从10到15的记录 2y\E[j A
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc j a[Et/r
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三、技巧 n)/z0n!\
1、1=1,1=2的使用,在SQL语句组合时用的较多 n6=By|jRh
"where 1=1" 是表示选择全部 "where 1=2"全部不选, &<g|gsG`
如: <\y@*fg+
if @strWhere !='' Oxnp0 s
begin u]wZQl#-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere R+:yVi[F]U
end !.$I["/=
else hF?1y `20
begin _RYxD"my
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' L- iy
end h
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我们可以直接写成 ? V1*cVD6i
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;a!S!%.h
2、收缩数据库 >{]%F*p4
--重建索引 g'f@H-KCD
DBCC REINDEX @u+]aI!`-
DBCC INDEXDEFRAG Z#jZRNU%ox
--收缩数据和日志 &AMl:@p9
DBCC SHRINKDB GAzU?a{S
DBCC SHRINKFILE A QU+mo
3、压缩数据库 ?,Xw[pR
dbcc shrinkdatabase(dbname) KkyVSoD\
4、转移数据库给新用户以已存在用户权限 ;C#F>SG\S
exec sp_change_users_login 'update_one','newname','oldname' pad*oPH,
go S}3fr^{.
5、检查备份集 q_8+HEvo
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' FXCMR\BsQ
6、修复数据库 5~U/
ALTER DATABASE [dvbbs] SET SINGLE_USER +/7?HGf
GO \\ij(>CI
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK P5V}#;v
GO =?*!"&h
ALTER DATABASE [dvbbs] SET MULTI_USER UgRiIQMq.
GO wu6;.xTLl
7、日志清除 s)t@ol
SET NOCOUNT ON nAato\mM
DECLARE @LogicalFileName sysname, `hm-.@f,9
@MaxMinutes INT, C&f=
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@NewSize INT h4}84}5d
USE tablename -- 要操作的数据库名 @{e}4s?7od
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9RL`<,Q
@MaxMinutes = 10, -- Limit on time allowed to wrap log. zk+9'r`-D
@NewSize = 1 -- 你想设定的日志文件的大小(M) aKDKmHd
-- Setup / initialize 1~FOgk1;
DECLARE @OriginalSize int gg/-k;@ Rf
SELECT @OriginalSize = size 0> E r=,e
FROM sysfiles :4w ?#
WHERE name = @LogicalFileName 3`?7<YJ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Pm?KI<TH~
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + *a^(vo
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1H`,WQ1mG
FROM sysfiles MJ)RvNF
WHERE name = @LogicalFileName A\DCW
CREATE TABLE DummyTrans Lb-OsKU
(DummyColumn char (8000) not null) #%2rP'He
DECLARE @Counter INT, {TROoX~H?
@StartTime DATETIME, 4"ZP 'I;
@TruncLog VARCHAR(255) I
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SELECT @StartTime = GETDATE(), gJ+'W1$/
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Rv>-4@fMJ
DBCC SHRINKFILE (@LogicalFileName, @NewSize) =XQ%t
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EXEC (@TruncLog) R29~~IOqO
-- Wrap the log if necessary. 9=tIz
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ~8+ Zs
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {Xy5pfW
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AND (@OriginalSize * 8 /1024) > @NewSize G_JA-@i%
BEGIN -- Outer loop. HJH{nz'Lw
SELECT @Counter = 0 |e&\<LwsP
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) (9d &
BEGIN -- update NxY#NaE:?4
INSERT DummyTrans VALUES ('Fill Log') 0mVNQxHI
DELETE DummyTrans t@;p
SELECT @Counter = @Counter + 1 6MW{,N
END ~~P5k:
EXEC (@TruncLog) (CL%>5V
END 0+ '&`Q!u
SELECT 'Final Size of ' + db_name() + ' LOG is ' + $PPi5f}HD
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + X?',n
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^ytrK
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FROM sysfiles uzPVTo|=
WHERE name = @LogicalFileName +\A,&;!SR
DROP TABLE DummyTrans <lPG=Xt
SET NOCOUNT OFF ;'K5J9k
8、说明:更改某个表 ]6`%
exec sp_changeobjectowner 'tablename','dbo' 0d&6lqTo
9、存储更改全部表 ITBE|b
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch G` A4|+W"
@OldOwner as NVARCHAR(128), T^KKy0ZGM
@NewOwner as NVARCHAR(128) 8nJpp
AS t:Q*gWRh
DECLARE @Name as NVARCHAR(128) Kc-W&?~y#1
DECLARE @Owner as NVARCHAR(128) =T@1@w
DECLARE @OwnerName as NVARCHAR(128) SnfYT)Ph
DECLARE curObject CURSOR FOR o.!Dq7R
select 'Name' = name, AkV#J,
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'Owner' = user_name(uid) =,8]nwgo
from sysobjects q} >%8;nm
where user_name(uid)=@OldOwner
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order by name ,"ZMRq
OPEN curObject eauF~md,
FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) i.m^/0!
BEGIN ~?BXti<!
if @Owner=@OldOwner /4Gt{ygSr
begin :I#V.
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5]0<9a
exec sp_changeobjectowner @OwnerName, @NewOwner }7Q% 6&IR
end l_p2Riv
-- select @name,@NewOwner,@OldOwner K0>zxqY
FETCH NEXT FROM curObject INTO @Name, @Owner 77Y/!~kd
END (<9u-HF#
close curObject K"MX!
deallocate curObject S9.o/mr
GO KWHY4
10、SQL SERVER中直接循环写入数据 g7H(PF?
declare @i int fJg+ Ryo
set @i=1 ]/v[8dS(l
while @i<30 WyiQoN'q
begin 9.#<b|g
insert into test (userid) values(@i) o]V^};B
set @i=@i+1 GbI/4<)l}
end Z`i(qCAd(
小记存储过程中经常用到的本周,本月,本年函数 ]-#DB^EQ
Dateadd(wk,datediff(wk,0,getdate()),-1) _[BP0\dPW
Dateadd(wk,datediff(wk,0,getdate()),6) \FaP|28h
Dateadd(mm,datediff(mm,0,getdate()),0) L/K(dkx
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "tK=+f`NM
Dateadd(yy,datediff(yy,0,getdate()),0) At;LO9T3z
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~}
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上面的SQL代码只是一个时间段 +}AI@+
Dateadd(wk,datediff(wk,0,getdate()),-1) ]SEZaT
Dateadd(wk,datediff(wk,0,getdate()),6) 307I$*%W
就是表示本周时间段. R=?[Nz
下面的SQL的条件部分,就是查询时间段在本周范围内的: A#,ZUOPGH
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6)
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而在存储过程中 h";L
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?Bmb' 3
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) :`sUt1Fw.