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。 |RQ19m@
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一、基础 2Mx9Kd'a
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1、说明:创建数据库 Z(AI]wk3<
CREATE DATABASE database-name 11}fPWK
2、说明:删除数据库 .?b2Bd!MC
drop database dbname Oqzz9+
3、说明:备份sql server ~o`I[-g)
--- 创建 备份数据的 device -ecP@,
USE master 0;'kv|
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' _+K[1P
--- 开始 备份 4cK6B)X
BACKUP DATABASE pubs TO testBack UJkg|eu
4、说明:创建新表 Z~o*$tF/
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) )AOD~T4s7
根据已有的表创建新表: 'j=7'aX>K
A:create table tab_new like tab_old (使用旧表创建新表) TDg#O!DUF
B:create table tab_new as select col1,col2... from tab_old definition only }~dXz?{p8
5、说明:删除新表 "H>L!v
drop table tabname ;J pdnV
6、说明:增加一个列 q4vu r>m6
Alter table tabname add column col type 10dVV[=
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 6~\z]LZ
7、说明:添加主键: Alter table tabname add primary key(col) uf,4GPo,
说明:删除主键: Alter table tabname drop primary key(col) N$J)Ow
8、说明:创建索引:create [unique] index idxname on tabname(col....) a#W:SgE?Y
删除索引:drop index idxname wL,b.]
注:索引是不可更改的,想更改必须删除重新建。 p~M1}mE
9、说明:创建视图:create view viewname as select statement fAWjk&9
删除视图:drop view viewname }NPF]P;
10、说明:几个简单的基本的sql语句 We3*WsX\
选择:select * from table1 where 范围 Iw~3y{\
插入:insert into table1(field1,field2) values(value1,value2) Y?hC/6$7
删除:delete from table1 where 范围 8Dpf{9Y-E
更新:update table1 set field1=value1 where 范围 ABEC{3fWpu
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! }AG$E}~/
排序:select * from table1 order by field1,field2 [desc] Ltpd:c
总数:select count as totalcount from table1 ~T<#HSR`
求和:select sum(field1) as sumvalue from table1 HGmgQ>q@M$
平均:select avg(field1) as avgvalue from table1 s)<#a(!
最大:select max(field1) as maxvalue from table1 1QM*oj:
最小:select min(field1) as minvalue from table1 J=>?D@K
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11、说明:几个高级查询运算词 aR.1&3fE
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A: UNION 运算符 xbrxh-gV
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。 Ay<'Z6`
B: EXCEPT 运算符 m`
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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。 dC@aQi6{6
C: INTERSECT 运算符 9Qp39(l:
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。 W<TW6_*e
注:使用运算词的几个查询结果行必须是一致的。 +4ax~fuU
12、说明:使用外连接 UiS9uGj
A、left outer join: a_I!2w<I
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。 a8aEZ724
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 qVC_K/w
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B:right outer join: &V1N
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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。 S{j|("W"[
C:full outer join: evPr~_
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。 a>`\^>G4
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二、提升 ` =dD6r
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) PaV [{CD
法一:select * into b from a where 1<>1 &oiX/UaY
法二:select top 0 * into b from a gs 8w/
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) rq9{m(
insert into b(a, b, c) select d,e,f from b; nL@
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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) hC<X\yxe
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 FCQoz"M
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 8YraW| H
4、说明:子查询(表名1:a 表名2:b) r9@O`i
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) B?-RzWB\3
5、说明:显示文章、提交人和最后回复时间 y4)M,+O5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b uOc>~ITPS
6、说明:外连接查询(表名1:a 表名2:b) :w(J=0Lt
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c mp0p#8txi
7、说明:在线视图查询(表名1:a ) +]
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select * from (SELECT a,b,c FROM a) T where t.a > 1; sW+YfJT
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 %Rr!I:[ $
select * from table1 where time between time1 and time2 ? AP2Opsl
select a,b,c, from table1 where a not between 数值1 and 数值2 TW).j6@f
9、说明:in 的使用方法 %@ $h?HP
select * from table1 where a [not] in ('值1','值2','值4','值6') ]R}#3(]1
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Ri4_zb
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) VP\HPSp
11、说明:四表联查问题: rB?u.jn0T
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... &d`Umm]
12、说明:日程安排提前五分钟提醒 rMSB|*_
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 .=rv,PWjZ
13、说明:一条sql 语句搞定数据库分页 j2lo~J)
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 F}0QocD
14、说明:前10条记录 f2_LfbvH
select top 10 * form table1 where 范围 5}9-)\8=z
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) k@5#^G
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) !$AVlMnJ
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 J"|)?$d]z
(select a from tableA ) except (select a from tableB) except (select a from tableC) <qZXpQ#
17、说明:随机取出10条数据 K7<'4i~k
select top 10 * from tablename order by newid() jd l1Q<Z
18、说明:随机选择记录 =nFT0];
select newid() nSsVONHfa
19、说明:删除重复记录 NmST1pMk
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) = Ii@-C
20、说明:列出数据库里所有的表名 9~zh]deH
select name from sysobjects where type='U' Zqd&EOm
21、说明:列出表里的所有的 ,Ng3!2&$e
select name from syscolumns where id=object_id('TableName') =b32E^z,
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。 y4VCehdJ
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 <?52Svi}}
显示结果: -QIcBzw;q
type vender pcs cZ|D!1%
电脑 A 1 yt>Pf<AI
电脑 A 1 yNc>s/
光盘 B 2 <Nvw
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光盘 A 2 -6~*:zg,
手机 B 3 BArsj
手机 C 3 nen6!bw4
23、说明:初始化表table1 dVVeH\o
TRUNCATE TABLE table1 ro@Zbm;P
24、说明:选择从10到15的记录 uA
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |C'w] QYm
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三、技巧 ~0ZEnejy
1、1=1,1=2的使用,在SQL语句组合时用的较多 D\(,:_ge
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 78+H|bH8
如: *IGxa
if @strWhere !='' \*LMc69
begin n8[sR;r5f
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere x@DXW(
end sl6p/\_w
else {,IWjt &>
begin <ofXNv;`
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' X$/3
end \q3H#1A
我们可以直接写成 GOJi/R.{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere m80+b8b
2、收缩数据库 ~Zl`Ap
--重建索引 r4+w?=`
DBCC REINDEX Ez?vJDd
DBCC INDEXDEFRAG |r}%AN6+
--收缩数据和日志 T~"tex]
DBCC SHRINKDB ZhxMA*fL
DBCC SHRINKFILE +D?d)lK
3、压缩数据库 YtW#MG$f
dbcc shrinkdatabase(dbname) @kvp2P+O
4、转移数据库给新用户以已存在用户权限 JsnavI6
exec sp_change_users_login 'update_one','newname','oldname' bIp;$ZHy`K
go `6~*kCj5
5、检查备份集 t)cG_+rJ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' G]P4[#5
6、修复数据库 c::x.B"w
ALTER DATABASE [dvbbs] SET SINGLE_USER Lom%eoH)
GO
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 82$By]Y9
GO eoEb\zJ
ALTER DATABASE [dvbbs] SET MULTI_USER {6 #3`
GO x ?^c:`.
7、日志清除 3;>(W
SET NOCOUNT ON wB9IP{Pf
DECLARE @LogicalFileName sysname, L%B+V;<h3
@MaxMinutes INT, =v:_N.Fh-c
@NewSize INT r0\bi6;s/
USE tablename -- 要操作的数据库名 DIk$9$"<x
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 W**=X\"'
@MaxMinutes = 10, -- Limit on time allowed to wrap log. .kC}. Q_
@NewSize = 1 -- 你想设定的日志文件的大小(M) H kg@M?(
-- Setup / initialize /@3+zpaw X
DECLARE @OriginalSize int #H!~:Xu
SELECT @OriginalSize = size (R6ZoBZ
FROM sysfiles S<Q1
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WHERE name = @LogicalFileName <(f4#BP
SELECT 'Original Size of ' + db_name() + ' LOG is ' + K"}Dbr
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \W=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' GK&yP%Z3
FROM sysfiles cYbO)?mC_
WHERE name = @LogicalFileName +D
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CREATE TABLE DummyTrans I]k'0LG*^
(DummyColumn char (8000) not null) <ht>>
DECLARE @Counter INT, Phb<##OB
@StartTime DATETIME,
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@TruncLog VARCHAR(255) ~B=\![
SELECT @StartTime = GETDATE(), 2~ 'Q#(
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' <U~P-c
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) Q@$1!9m
EXEC (@TruncLog) $hKgTf?
-- Wrap the log if necessary. \&TTe8
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired E32z(:7M
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ise@,[!
AND (@OriginalSize * 8 /1024) > @NewSize SbGp
BEGIN -- Outer loop. OW-+23)sj
SELECT @Counter = 0 F)gL=6h
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Qb(CH
BEGIN -- update 5Q%#Z
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INSERT DummyTrans VALUES ('Fill Log') Y\op9Fw
DELETE DummyTrans Xrz0ch
SELECT @Counter = @Counter + 1 R=e`QMq
END Q'8v!/"}p{
EXEC (@TruncLog) l w%fY{
END kkJg/:g
SELECT 'Final Size of ' + db_name() + ' LOG is ' + y.O? c&!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + r p@=
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' IcQ?^9%{
FROM sysfiles Z(<ul<?r
WHERE name = @LogicalFileName piId5Gx7
DROP TABLE DummyTrans 7Ru0>4B
SET NOCOUNT OFF AGv;8'`
8、说明:更改某个表 .s!:p pwl
exec sp_changeobjectowner 'tablename','dbo' PN'8"8`{
9、存储更改全部表 >|iy= Zn%'
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch `2@-'/$\I|
@OldOwner as NVARCHAR(128), C$tSsw?A
@NewOwner as NVARCHAR(128) "|Pl(HX
AS /C(L(X
DECLARE @Name as NVARCHAR(128) xJ"KR:CD>
DECLARE @Owner as NVARCHAR(128) a 6 ]!4
DECLARE @OwnerName as NVARCHAR(128) sW]n~kTt'
DECLARE curObject CURSOR FOR N!m%~},s//
select 'Name' = name, \O0fo^+U,,
'Owner' = user_name(uid) r[,KE.^6~#
from sysobjects @"~\[z5
where user_name(uid)=@OldOwner <]9MgfAe
order by name !e7vc[N
OPEN curObject y&CUT:M6
FETCH NEXT FROM curObject INTO @Name, @Owner E$1^}RGT)
WHILE(@@FETCH_STATUS=0) 9:Y:Vx
BEGIN jqLyX
if @Owner=@OldOwner RhJ<<T.2
begin H 0h
set @OwnerName = @OldOwner + '.' + rtrim(@Name) pP
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exec sp_changeobjectowner @OwnerName, @NewOwner {10ms_s
end tS9m8(Hr%Q
-- select @name,@NewOwner,@OldOwner [qXpi'q[
FETCH NEXT FROM curObject INTO @Name, @Owner 7d<v\=J}
END z=fag'fzM
close curObject 1]<!Xuk^f
deallocate curObject 9F-k:hD |
GO W+eN%w5
10、SQL SERVER中直接循环写入数据 ms{R|vU%b
declare @i int oF>GWstTR
set @i=1 =QC^7T
while @i<30 e"2QV vB
begin OP&[5X+Y
insert into test (userid) values(@i) 68!]q(!6F
set @i=@i+1 SH(kUL5
end vr vzV
小记存储过程中经常用到的本周,本月,本年函数 RasoOj$
Dateadd(wk,datediff(wk,0,getdate()),-1) 4w?7AI]Ej
Dateadd(wk,datediff(wk,0,getdate()),6) g}D$`Nx:
Dateadd(mm,datediff(mm,0,getdate()),0) 9=o
b:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) L!p|RKz9X
Dateadd(yy,datediff(yy,0,getdate()),0) C:K\-P9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) k|_2aQ02
上面的SQL代码只是一个时间段 J#kdyBmuO
Dateadd(wk,datediff(wk,0,getdate()),-1) G<z)Ydh_
Dateadd(wk,datediff(wk,0,getdate()),6) @Dy.HQ~
就是表示本周时间段. 6Te}"t>
下面的SQL的条件部分,就是查询时间段在本周范围内的: m7"f6zSo(
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) c`+ITNV
而在存储过程中
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) w|HZI,~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) _R<HC