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。 .f(x9|K^
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一、基础 5zfaqt`
1、说明:创建数据库 KS(s<ip|
CREATE DATABASE database-name {CQA@p:Y}
2、说明:删除数据库 lQ!6n
drop database dbname !u\ X,.h
3、说明:备份sql server n~K_|
--- 创建 备份数据的 device Q4c>gds`
USE master YEVH?`G
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' zJdlHa{
--- 开始 备份 / x$O6gi
BACKUP DATABASE pubs TO testBack D_@r_^}
4、说明:创建新表 q'K=Ly+
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) r%_)7Wk*
根据已有的表创建新表: ZZl)p\r
A:create table tab_new like tab_old (使用旧表创建新表) eT}c_h)
B:create table tab_new as select col1,col2... from tab_old definition only G'{4ec0<{
5、说明:删除新表 s)ZL`S?</
drop table tabname mjB%"w!S
6、说明:增加一个列 ||qsoF5B]
Alter table tabname add column col type sEhdkN}6
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 A5?[j
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7、说明:添加主键: Alter table tabname add primary key(col) nW{7L
说明:删除主键: Alter table tabname drop primary key(col) -] J V
8、说明:创建索引:create [unique] index idxname on tabname(col....) 3(AgUq
删除索引:drop index idxname bX5>qqB]
注:索引是不可更改的,想更改必须删除重新建。 1{nXmtvr
9、说明:创建视图:create view viewname as select statement Y}nE/bmx&9
删除视图:drop view viewname eCk}B$ 2
10、说明:几个简单的基本的sql语句 NsWyxcty
选择:select * from table1 where 范围 Ej6vGC.,
插入:insert into table1(field1,field2) values(value1,value2) ir%/9=^d
删除:delete from table1 where 范围 x\x>_1oP
更新:update table1 set field1=value1 where 范围 Zroj-3-X~
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! qjUQ2d
排序:select * from table1 order by field1,field2 [desc] u4#BD!W
总数:select count as totalcount from table1 WI}P(!h\J
求和:select sum(field1) as sumvalue from table1 FS1<f:
平均:select avg(field1) as avgvalue from table1 \7gLk:
最大:select max(field1) as maxvalue from table1 9Z
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最小:select min(field1) as minvalue from table1 ;t"#7\
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11、说明:几个高级查询运算词 )ZNH/9e/
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A: UNION 运算符 k\x>kJ}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。 kQ{pFFO
B: EXCEPT 运算符 ,}`II|.oB
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。
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C: INTERSECT 运算符 (AXSQI~y
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。 I&R4.;LW
注:使用运算词的几个查询结果行必须是一致的。 m:Z=: -x
12、说明:使用外连接 yWt87+%T
A、left outer join: V\)@Yk2
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。 6^UeEmjc
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 0'z$"(6D
B:right outer join: !*+~R2&b
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 )Hl;9
C:full outer join: SvDVxK
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Tv~<W4
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二、提升 5XA6IL|/l
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )}n`MRDB
法一:select * into b from a where 1<>1 -4;{QB?
法二:select top 0 * into b from a /e#_Yg
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) u -CY-
insert into b(a, b, c) select d,e,f from b; ,j9}VnW)
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) R;'Pe>
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {$O.@#'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. m{gt(n
4、说明:子查询(表名1:a 表名2:b) :4&qASn
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) xJN
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5、说明:显示文章、提交人和最后回复时间 Lgvmk
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b
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6、说明:外连接查询(表名1:a 表名2:b) & UL(r
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [
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7、说明:在线视图查询(表名1:a ) KuE
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select * from (SELECT a,b,c FROM a) T where t.a > 1; 'UW7zL5
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 waO*CjxE:
select * from table1 where time between time1 and time2 C37KvLQ
select a,b,c, from table1 where a not between 数值1 and 数值2 fLct!H3
9、说明:in 的使用方法 jD$T
select * from table1 where a [not] in ('值1','值2','值4','值6') ryN/sjQC
10、说明:两张关联表,删除主表中已经在副表中没有的信息 !u>29VN
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) u|O5ZV-cd
11、说明:四表联查问题: 2+
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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 ..... Yz\z
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12、说明:日程安排提前五分钟提醒 l|U=(aA]h
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 .5KRi6
13、说明:一条sql 语句搞定数据库分页 osPX%k!yw
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 Xk(c2s&
14、说明:前10条记录 V:F)m!
select top 10 * form table1 where 范围 9'td}S
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.) &hyr""NkAm
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Y
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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 x_bS-B)%Y:
(select a from tableA ) except (select a from tableB) except (select a from tableC) D3(|bSca
17、说明:随机取出10条数据 JU/K\S2%,
select top 10 * from tablename order by newid() |W`1#sP>
18、说明:随机选择记录 Y@_ i32,r
select newid()
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19、说明:删除重复记录 SYeCz(H>d
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) L?4c8!Q
20、说明:列出数据库里所有的表名 gWv/3hWWB
select name from sysobjects where type='U' $zyY"yWRZ
21、说明:列出表里的所有的 <yE(p
select name from syscolumns where id=object_id('TableName') 0[);v/@Ho
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 s|%mGt &L
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type b3<<4Vf
显示结果: AX<TkS@wjb
type vender pcs }!lLA4XRr
电脑 A 1 }bAd@a9>3
电脑 A 1 vC&y:XMt,`
光盘 B 2 >2vl & (
光盘 A 2 !`)-seTm
手机 B 3 :7@"EW
手机 C 3 OZQhT)nS]
23、说明:初始化表table1 _I3j7f,V
TRUNCATE TABLE table1 86vk"
24、说明:选择从10到15的记录 Rfeiv
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc fPZBm&`C
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三、技巧 gB71~A{J
1、1=1,1=2的使用,在SQL语句组合时用的较多 Xe:B*
"where 1=1" 是表示选择全部 "where 1=2"全部不选, nBWrkVX
如: ^['% wA%
if @strWhere !='' ov*zQP
begin Ga+\b>C
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere fw|r{#d
end XDz![s
else TM[Z~n(wt
begin Ep.,2H
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' #xm<|s
end Cdotl$'
我们可以直接写成 FavU"QU&|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere n|yl3v
2、收缩数据库 1Jd82N\'
--重建索引 1;080|,s
DBCC REINDEX K>,Kbs=D6
DBCC INDEXDEFRAG Y%anR|
--收缩数据和日志 `m`jX|`
DBCC SHRINKDB Lk4&&5q
DBCC SHRINKFILE /n/U)!tp
3、压缩数据库 W6E9
dbcc shrinkdatabase(dbname) f(|qE(
4、转移数据库给新用户以已存在用户权限 0{gvd"q
exec sp_change_users_login 'update_one','newname','oldname' v>~ottQ|
go lk2F]@_kJH
5、检查备份集 vXq=f:y4
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' PF1!aAvVb
6、修复数据库 Kg~<h B6
ALTER DATABASE [dvbbs] SET SINGLE_USER rcF;Lp :
GO 3k5Mty
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK bxqXFy/I
GO F2AM/m^!q
ALTER DATABASE [dvbbs] SET MULTI_USER {ylc2 1
GO J,4]du$
7、日志清除 |.*),t3
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SET NOCOUNT ON pvDr&n9
DECLARE @LogicalFileName sysname, HJ !)D~M{
@MaxMinutes INT, zVGjXuNa
@NewSize INT 42Tjbten_u
USE tablename -- 要操作的数据库名 zi:GvTG
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \G#Qe*"'K
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #-
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@NewSize = 1 -- 你想设定的日志文件的大小(M) bqsb (C
-- Setup / initialize slOki|p;
DECLARE @OriginalSize int T9*\ITA
SELECT @OriginalSize = size JihI1C
FROM sysfiles iL/(WAB_od
WHERE name = @LogicalFileName >XSe[K
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \-#~)LB]M
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ]BO{Q+?d2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' L<1"u.3Z`}
FROM sysfiles =yz#L@\!
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans (W5E\hjJ
(DummyColumn char (8000) not null) 5#80`/w^U
DECLARE @Counter INT, jMzHs*:
@StartTime DATETIME, qaA\.h7
@TruncLog VARCHAR(255) ig")bt3s5
SELECT @StartTime = GETDATE(), ]i8K )/
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >|o-&dk
DBCC SHRINKFILE (@LogicalFileName, @NewSize) --Dw
EXEC (@TruncLog) c1jHg2xim
-- Wrap the log if necessary. 0`h[|FYV
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Jk}L+Xvv
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) P qagep d
AND (@OriginalSize * 8 /1024) > @NewSize 69dFd!G\
BEGIN -- Outer loop. +&4PGv53J
SELECT @Counter = 0 E,c~.jYc
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) f8#WT$Ewy
BEGIN -- update -E2[PW4$
INSERT DummyTrans VALUES ('Fill Log') J.$<Lnt>u
DELETE DummyTrans 7. G
SELECT @Counter = @Counter + 1 o!q9pt
END /JEH%)
EXEC (@TruncLog) (|'w$
END e&OMW,7
SELECT 'Final Size of ' + db_name() + ' LOG is ' + _-%ay
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + lE?e1mz{
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' V*=cNj
FROM sysfiles yD#w @yG
WHERE name = @LogicalFileName { )'D<:T
DROP TABLE DummyTrans `RthX\Tof
SET NOCOUNT OFF !V+5$TsS
8、说明:更改某个表 F}H!vh[
exec sp_changeobjectowner 'tablename','dbo' AU^Wy|i5Q
9、存储更改全部表 ~H@':Mms.h
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch yz9`1R2c
@OldOwner as NVARCHAR(128), HoH3.AY X
@NewOwner as NVARCHAR(128) @Sq=#f/=
AS 7@fd[
DECLARE @Name as NVARCHAR(128) !Ya
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DECLARE @Owner as NVARCHAR(128) ~_8Ve\Y^ /
DECLARE @OwnerName as NVARCHAR(128) B
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DECLARE curObject CURSOR FOR Y@9L8XNP>
select 'Name' = name, Tb IM{X
'Owner' = user_name(uid) nd3]&occ
from sysobjects 7KRc^ *pZs
where user_name(uid)=@OldOwner ~e
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order by name t<ftEJU"'w
OPEN curObject S/~6%uJ
FETCH NEXT FROM curObject INTO @Name, @Owner r;|Bc$P
WHILE(@@FETCH_STATUS=0) @T;O^rE~N
BEGIN 6|T{BOW!d
if @Owner=@OldOwner [cXu<vjFM
begin O<6/0ub&+h
set @OwnerName = @OldOwner + '.' + rtrim(@Name) l>~:lBO
exec sp_changeobjectowner @OwnerName, @NewOwner X2M<DeF:
end puZ<cV
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-- select @name,@NewOwner,@OldOwner iL|*g3`-f
FETCH NEXT FROM curObject INTO @Name, @Owner uqTOEHH7
END kgr:85
close curObject @h>#cwhU
deallocate curObject zHb<YpU
GO 4 3]6J]!)
10、SQL SERVER中直接循环写入数据 :e+GtN?
declare @i int hf:n!+,C
set @i=1 &Eidc .
while @i<30 a(x[+ El
begin aCGPtA'
insert into test (userid) values(@i) i$"FUC~'
set @i=@i+1 &\<RVE
end B
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小记存储过程中经常用到的本周,本月,本年函数 o<Y|N
Dateadd(wk,datediff(wk,0,getdate()),-1) +bdkqdB9
Dateadd(wk,datediff(wk,0,getdate()),6) )Bb :tz+
Dateadd(mm,datediff(mm,0,getdate()),0) k\ I$ve"*
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "MoV*U2s,
Dateadd(yy,datediff(yy,0,getdate()),0) ^ /
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Sw5H+!
上面的SQL代码只是一个时间段 /R|"/B0
Dateadd(wk,datediff(wk,0,getdate()),-1) _&
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Dateadd(wk,datediff(wk,0,getdate()),6) +S;8=lzuV
就是表示本周时间段. s3J T1TX
下面的SQL的条件部分,就是查询时间段在本周范围内的: d57(#)`
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) mG?a)P
而在存储过程中 }Q\yem
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) WCR+ZXI?1
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) elKQge