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。 >ByXB!Wi+
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一、基础 GBFtr
1、说明:创建数据库 D]~MC
CREATE DATABASE database-name _DNHc*
2、说明:删除数据库 j;3[KLmuK%
drop database dbname :WL'cJ9a
3、说明:备份sql server #x3ujJ
--- 创建 备份数据的 device FE!lok
USE master sHl>$Qevz
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `zXO_@C
--- 开始 备份 #ap9Yoyk\
BACKUP DATABASE pubs TO testBack WT`4s
4、说明:创建新表 D{4YxR
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [$"n^5_~
根据已有的表创建新表: pV,P|>YTf
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only /BV03B
5、说明:删除新表 J8)#PY[i4
drop table tabname hq/k*;
6、说明:增加一个列 MxcFvo*LCp
Alter table tabname add column col type wz.6du6-
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。 7=OQ8IM!
7、说明:添加主键: Alter table tabname add primary key(col) H4!+q:<
说明:删除主键: Alter table tabname drop primary key(col) /E5 5Pec
8、说明:创建索引:create [unique] index idxname on tabname(col....) ^:* 1d
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删除索引:drop index idxname Z(_ZAB%+D
注:索引是不可更改的,想更改必须删除重新建。 *`Yv.=cd
9、说明:创建视图:create view viewname as select statement JEgx@};O
删除视图:drop view viewname Ox'/`Mppw
10、说明:几个简单的基本的sql语句 >P $;79<
选择:select * from table1 where 范围 /<8N\_wh
插入:insert into table1(field1,field2) values(value1,value2) `zt_7MD
删除:delete from table1 where 范围 Vy,^)]
更新:update table1 set field1=value1 where 范围 [.*;6y3
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! f'{]"^e=
排序:select * from table1 order by field1,field2 [desc] !o+_T?
总数:select count as totalcount from table1 S^<g_ q
求和:select sum(field1) as sumvalue from table1 L%c0 Z@[~
平均:select avg(field1) as avgvalue from table1 b2=0}~LK
最大:select max(field1) as maxvalue from table1 'fNKlPMv4D
最小:select min(field1) as minvalue from table1 <rL/B
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11、说明:几个高级查询运算词 %8M)2?E
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A: UNION 运算符 =)`
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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。 t2iv(swTe
B: EXCEPT 运算符 $gM8{.!
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 <K4,7J$}h
C: INTERSECT 运算符 ZzBQe
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。 U}l14
注:使用运算词的几个查询结果行必须是一致的。 zf>5,k'x'A
12、说明:使用外连接 FwZ>{~?3
A、left outer join: 5W@jfh)
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。 v[n7"
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 D.6,VY H
B:right outer join: wL^%w9q-
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。 l-$uHHyu*
C:full outer join: hy T1xa
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 \VFHHi:I
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二、提升 Pv+5K*"7Cg
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) V@QK
法一:select * into b from a where 1<>1 TSsKfexQ
法二:select top 0 * into b from a y tf b$;|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) \yGsr Bl
insert into b(a, b, c) select d,e,f from b; !GQ\"Ufs>
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) ulJX1I=|p
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 AVU>+[.=%c
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hw~a:kD
4、说明:子查询(表名1:a 表名2:b) 79yd&5#e?
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) 5+jf/}tA
5、说明:显示文章、提交人和最后回复时间 [
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @ Ehn(}
6、说明:外连接查询(表名1:a 表名2:b) S"hTE7`
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c S$^RbI
7、说明:在线视图查询(表名1:a ) GzTq5uU&
select * from (SELECT a,b,c FROM a) T where t.a > 1; Iu35#j
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括
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select * from table1 where time between time1 and time2 )CS.F=
select a,b,c, from table1 where a not between 数值1 and 数值2 `K
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9、说明:in 的使用方法 b]JI@=s?
select * from table1 where a [not] in ('值1','值2','值4','值6') J!*/a'Cv
10、说明:两张关联表,删除主表中已经在副表中没有的信息 'XUKN/.
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 7RvUH-S[
11、说明:四表联查问题: e%>b+Sv
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... A[YpcG'9
12、说明:日程安排提前五分钟提醒 }V|{lvt.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 @v*/R%rv t
13、说明:一条sql 语句搞定数据库分页 5Fm=/o1
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 |uH%6&\
14、说明:前10条记录 Px>va01n
select top 10 * form table1 where 范围 Q9`QL3LQD
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.)
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) /)rkiwp
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 WWZ9._
(select a from tableA ) except (select a from tableB) except (select a from tableC) 1]T`n /d V
17、说明:随机取出10条数据 2qO3XI
select top 10 * from tablename order by newid() nB ". '=
18、说明:随机选择记录 Jj^GWZRu
select newid() Z_1*YRBY;
19、说明:删除重复记录 (:+>#V)pZ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) T^}
20、说明:列出数据库里所有的表名 l**;k+hw
select name from sysobjects where type='U' RP`2)/sMT
21、说明:列出表里的所有的 p=QYc)3F
select name from syscolumns where id=object_id('TableName') <vbIp&
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 i$KpDXP\
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 OlQ,Ce
显示结果: ^ 2u/n
type vender pcs l48k<
电脑 A 1 1Ee>S\9t
电脑 A 1 r
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光盘 B 2 >uI$^y1D
光盘 A 2 2n`Lg4=
手机 B 3 9%iFV
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手机 C 3 d=]U_+
23、说明:初始化表table1 0%;146.p
TRUNCATE TABLE table1 ^aRgMuU
24、说明:选择从10到15的记录 ~ekh1^evu
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc KIVH!2q;
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三、技巧 I}Xg&-L
1、1=1,1=2的使用,在SQL语句组合时用的较多 vVs#^"-nW
"where 1=1" 是表示选择全部 "where 1=2"全部不选, )DUL)S
如: y/@iT8$rp
if @strWhere !='' %E27.$E_
begin ~-F?Mc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere uC]Z8&+obb
end 7=*VpX1
else [Id}4[={e
begin IGAzE(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' n`;R pr&
end O:.,+,BH
我们可以直接写成 i`OrMzL
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere qU[O1bN
2、收缩数据库 !|m9|
--重建索引 ! ]Mc4!E
DBCC REINDEX 9''p[V.3
DBCC INDEXDEFRAG 1:= `Y@.S
--收缩数据和日志 YJ2ro-X
DBCC SHRINKDB []&(D_e"
DBCC SHRINKFILE 9F+ P@Kp
3、压缩数据库 aN^IP
dbcc shrinkdatabase(dbname) hGP1(pH.
4、转移数据库给新用户以已存在用户权限 s([Wn)I
exec sp_change_users_login 'update_one','newname','oldname' <2P7utdZ
go )8{6+{5lu
5、检查备份集 rvwy~hO"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' hWcTI{v
6、修复数据库 I/UQ' xx
ALTER DATABASE [dvbbs] SET SINGLE_USER 77:'I
GO ?|t/mo|K?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK w&lZ42(mF
GO 5su.+4z\
ALTER DATABASE [dvbbs] SET MULTI_USER f(u&XuZ
GO vg8O]
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7、日志清除 iG[?
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SET NOCOUNT ON Ds5NAp:x
DECLARE @LogicalFileName sysname, ^@}#me@
@MaxMinutes INT, Eqphd!\#6
@NewSize INT GH3#E*t+[
USE tablename -- 要操作的数据库名 Qp!Y.YnPd_
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 *PM}"s
@MaxMinutes = 10, -- Limit on time allowed to wrap log. IF?xnu
@NewSize = 1 -- 你想设定的日志文件的大小(M) -WT3)On
-- Setup / initialize e!o(g&wBj
DECLARE @OriginalSize int cj(X2L
SELECT @OriginalSize = size hswTn`f
FROM sysfiles <FmBa4ONU
WHERE name = @LogicalFileName XS0V:<+,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {~GR8
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + WaYO1*=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' u;n(+8sz
FROM sysfiles 1| xN%27>
WHERE name = @LogicalFileName |ft:|/^F&
CREATE TABLE DummyTrans 2;N@aZX
(DummyColumn char (8000) not null) d~[UXQC
DECLARE @Counter INT, x9}++r
@StartTime DATETIME, 9p>
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@TruncLog VARCHAR(255) $au2%NL
SELECT @StartTime = GETDATE(), {of]/3=
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 0:dB
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) xYR#%! M
EXEC (@TruncLog) vbn>mg5
-- Wrap the log if necessary. a8h]n:!
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired G6Q4-kcK
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) `Ei"_W
AND (@OriginalSize * 8 /1024) > @NewSize m,NMTyJoz
BEGIN -- Outer loop. Mj~${vj
SELECT @Counter = 0 `45d"B
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) POBpJg
BEGIN -- update t&"5dM\
INSERT DummyTrans VALUES ('Fill Log') RWahsJTu
DELETE DummyTrans B/Ba5z"r$
SELECT @Counter = @Counter + 1 #Si|!
END 3Hm7
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EXEC (@TruncLog) caD5Pod4
END ,35Ag#va
SELECT 'Final Size of ' + db_name() + ' LOG is ' + deM~[1e[
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~N[|bPRmhE
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 3zb)"\(R
FROM sysfiles ma7fDo0,`h
WHERE name = @LogicalFileName slSR=XOG
DROP TABLE DummyTrans zH+<bEo=1=
SET NOCOUNT OFF P|N?OocE
8、说明:更改某个表 tQ0=p|
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exec sp_changeobjectowner 'tablename','dbo' ]hUKuef
9、存储更改全部表 ?-{IsF^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )[DpK=[N^p
@OldOwner as NVARCHAR(128), ;xW{Ehq-h
@NewOwner as NVARCHAR(128) Mw|SH;nM
AS #KJZR{
DECLARE @Name as NVARCHAR(128) ' PL_~
DECLARE @Owner as NVARCHAR(128) s?<!&Y
DECLARE @OwnerName as NVARCHAR(128) +UaO<L
DECLARE curObject CURSOR FOR dP3VJ3+
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select 'Name' = name, t~~r-V":
'Owner' = user_name(uid) kGj]i@(PA4
from sysobjects o*)@oU
where user_name(uid)=@OldOwner drX4$Kdf]
order by name &z0iLa4q)
OPEN curObject r!M#7FDs(
FETCH NEXT FROM curObject INTO @Name, @Owner u-M] Az-
WHILE(@@FETCH_STATUS=0) u~)%tL
BEGIN ok=40B99T
if @Owner=@OldOwner ={xqNRVd
begin '5cZzC
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) YlB["@\[B
exec sp_changeobjectowner @OwnerName, @NewOwner 5@.zz"o.`
end mdt
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-- select @name,@NewOwner,@OldOwner 2?H@$-x>
FETCH NEXT FROM curObject INTO @Name, @Owner T Xl\hL\+
END L)G">T;
close curObject r
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deallocate curObject [+7"{UvT
GO Fi k@hu
10、SQL SERVER中直接循环写入数据 Q^ q=!/qQ
declare @i int j%GbgJ
set @i=1 {"\q(R0
while @i<30 N
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begin (>r|j4$
insert into test (userid) values(@i) bN4d:0 Y
set @i=@i+1 T/5nu?v
end *<CxFy;|
小记存储过程中经常用到的本周,本月,本年函数 Obg@YIwn
Dateadd(wk,datediff(wk,0,getdate()),-1) %g5jY%dg.r
Dateadd(wk,datediff(wk,0,getdate()),6) @6[x%j/!bt
Dateadd(mm,datediff(mm,0,getdate()),0) l^BEFk;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \)s3b/oap
Dateadd(yy,datediff(yy,0,getdate()),0) TwwIt5_fN
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1+FYjh!2t
上面的SQL代码只是一个时间段 @ p"NJx"
Dateadd(wk,datediff(wk,0,getdate()),-1) hF9B?@n?B
Dateadd(wk,datediff(wk,0,getdate()),6) 1S^'C2/b
就是表示本周时间段. ,^M]yr*~
下面的SQL的条件部分,就是查询时间段在本周范围内的: Q{`@
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ]uJM6QuQ
而在存储过程中 mf#fA2[
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) f!^)!~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) MXh^dOWR