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。 i3f/{D/
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一、基础 +y -:(aP
1、说明:创建数据库 :<nL9y jt
CREATE DATABASE database-name :@Q_oyWE8
2、说明:删除数据库 d[ {=/~0
drop database dbname |Z!C`G[
3、说明:备份sql server ~PS%^zxyn
--- 创建 备份数据的 device Oi7:J>
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USE master M8
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' F2+lwyc Y
--- 开始 备份 NH|v`rO
BACKUP DATABASE pubs TO testBack h~<#1'/<
4、说明:创建新表 .llAiv
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~lQ]PKJ"
根据已有的表创建新表: ]\Ez{MdAT
A:create table tab_new like tab_old (使用旧表创建新表) mz/KGZ5t
B:create table tab_new as select col1,col2... from tab_old definition only |n]^gTJt
5、说明:删除新表 n)
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drop table tabname 6s>PZh
6、说明:增加一个列 Qza[~6
Alter table tabname add column col type 8B\,*JGY2
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。 _*&<hAZj
7、说明:添加主键: Alter table tabname add primary key(col) qB"y'UW8
说明:删除主键: Alter table tabname drop primary key(col) i"_JF-IbN
8、说明:创建索引:create [unique] index idxname on tabname(col....) r\L:JTZ$
删除索引:drop index idxname GVFD_;j'
注:索引是不可更改的,想更改必须删除重新建。 bx`(d@
9、说明:创建视图:create view viewname as select statement W*VQ"CW{^]
删除视图:drop view viewname >N44&W
10、说明:几个简单的基本的sql语句 !74*APPHR
选择:select * from table1 where 范围 8vnU!r
插入:insert into table1(field1,field2) values(value1,value2) g[!sGa&
删除:delete from table1 where 范围 '?Hy"5gUA
更新:update table1 set field1=value1 where 范围 K@W~
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! IgSe%B
排序:select * from table1 order by field1,field2 [desc] .8g&V|
总数:select count as totalcount from table1 mVk:[
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求和:select sum(field1) as sumvalue from table1 JCE364$$"
平均:select avg(field1) as avgvalue from table1 ,{YC|uB
最大:select max(field1) as maxvalue from table1 k98--kc5
最小:select min(field1) as minvalue from table1 +]UPY5:F
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11、说明:几个高级查询运算词 |n Mbf
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A: UNION 运算符 aiU n
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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。 `\#Qr|GC
B: EXCEPT 运算符 [NC^v.[1[
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。 \5X34'7
C: INTERSECT 运算符 {9Y@?
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。 [gD02a:u
注:使用运算词的几个查询结果行必须是一致的。 vO
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12、说明:使用外连接 zoO>N'b3)
A、left outer join: e@@kTny(
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。 5>$*#0%"}
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 XIf,#9
B:right outer join: Ho*S>Y
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。 }|Cw]GW
C:full outer join: EYMwg_
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 qE,zW
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二、提升 R],,-
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |0m h*+i
法一:select * into b from a where 1<>1 33-=Z9|r
法二:select top 0 * into b from a iZ)7%R?5
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +^4"
insert into b(a, b, c) select d,e,f from b; dqPJ 2j $\
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) i_f"?X;D
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 l,pq;>c9a
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. uV=rLDY
4、说明:子查询(表名1:a 表名2:b) 8={(Vf6
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) W9.ZhpM
5、说明:显示文章、提交人和最后回复时间 Bqa%L.N2SS
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b :|P"`j
6、说明:外连接查询(表名1:a 表名2:b) 3^wJ4=^
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c pHKj*Y
7、说明:在线视图查询(表名1:a ) )Z"7^i
select * from (SELECT a,b,c FROM a) T where t.a > 1; 9?l(
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 H=7dp%b"
select * from table1 where time between time1 and time2 z_r W1?|
select a,b,c, from table1 where a not between 数值1 and 数值2 oa47TqFt
9、说明:in 的使用方法 Hya*7l']B
select * from table1 where a [not] in ('值1','值2','值4','值6') ;I]TM#qGF
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Hm1C|Qb
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) d$b{KyUA
11、说明:四表联查问题: '}LH,H:%G
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 ..... (w4#?_
12、说明:日程安排提前五分钟提醒 m[]pIXc(
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 P?\rRB
13、说明:一条sql 语句搞定数据库分页
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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 Xs*~[k'
14、说明:前10条记录 Mx0c
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select top 10 * form table1 where 范围 7ug mZO}lL
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.) r'w5i1C+
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) b&V=X{V4
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 G74<sD
(select a from tableA ) except (select a from tableB) except (select a from tableC) `Fu|50_@V
17、说明:随机取出10条数据 ,T"(97"
select top 10 * from tablename order by newid() 3p$ZHH.UP
18、说明:随机选择记录 >TwOL
select newid() ~r&Q\G
19、说明:删除重复记录 u [fQvdl
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Cg8{NNeD
20、说明:列出数据库里所有的表名 Oj~k 1+*
select name from sysobjects where type='U' @q[-,EA9
21、说明:列出表里的所有的 T\. 8og
select name from syscolumns where id=object_id('TableName') E=HS'XKu[K
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。 }MuXN<DDb
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 v#=WdaNz
显示结果: tE<L4;t
type vender pcs _/P"ulNb
电脑 A 1 A]Q4fD1q
电脑 A 1 hq(3%- 7&
光盘 B 2 V ;"?='vVe
光盘 A 2 !Wn'Ae9
手机 B 3 }me]?en_Ra
手机 C 3 irgjq/&d
23、说明:初始化表table1 |0A n|18
TRUNCATE TABLE table1 >p2v"X X
24、说明:选择从10到15的记录 )bPwB.} kq
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >-EoE;s
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三、技巧 9S.R%2xw`
1、1=1,1=2的使用,在SQL语句组合时用的较多 kZSe#'R's
"where 1=1" 是表示选择全部 "where 1=2"全部不选, .oAg
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如: ~F
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if @strWhere !='' N~Ax78TX
begin 8t0i
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere rS)7D
end w.^k':,"
else Z*jhSy
begin ely&'y!
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' wp.'M?6`L
end m6+2rD
我们可以直接写成 PY)C=={p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere qt/"$6]%
2、收缩数据库 <$,iYx
--重建索引 y)Ip\.KV\
DBCC REINDEX E5-8tHV
DBCC INDEXDEFRAG r(%#@?&
--收缩数据和日志 :mL\KQ
DBCC SHRINKDB :t^=~xO9
DBCC SHRINKFILE F2>o"j2
3、压缩数据库 |)
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dbcc shrinkdatabase(dbname) G'}%m;-mt
4、转移数据库给新用户以已存在用户权限 .E[k}{k,
exec sp_change_users_login 'update_one','newname','oldname' 2!{CNt.-
go [@Uc4LX
5、检查备份集 LvhF@%(9J
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 2*%0m^#^6
6、修复数据库 yd#4b`8U`
ALTER DATABASE [dvbbs] SET SINGLE_USER r{p?aG
GO BYNOgB1
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK )1lYfJ
GO q\d'}:kfu
ALTER DATABASE [dvbbs] SET MULTI_USER &'T7 ~M:
GO ++Az~{W7
7、日志清除 gaTI:SKzc
SET NOCOUNT ON 78y4nRQ*
DECLARE @LogicalFileName sysname, dy|r:~j3
@MaxMinutes INT,
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@NewSize INT }^)M)8zS
USE tablename -- 要操作的数据库名 !\+SE"ml
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 gHYYxhW$
@MaxMinutes = 10, -- Limit on time allowed to wrap log. B6OggJ9Iq
@NewSize = 1 -- 你想设定的日志文件的大小(M) `'+[Y;s_
-- Setup / initialize |p.mA-81
DECLARE @OriginalSize int k<8:
SELECT @OriginalSize = size w}oH]jVKL6
FROM sysfiles l&;#`\s!V
WHERE name = @LogicalFileName qhL e[[>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + wyvs#T
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + >*vI:MG8
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (p^q3\
FROM sysfiles e,:@c3I
WHERE name = @LogicalFileName f0MHh5
CREATE TABLE DummyTrans R"=G?d)
(DummyColumn char (8000) not null) l.>QO ;
DECLARE @Counter INT, \HTXl]
@StartTime DATETIME, @i6D&e=
@TruncLog VARCHAR(255) .CwMxuW
SELECT @StartTime = GETDATE(), Ms^,]Q1{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 3u+~!yz
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {jggiMwo.v
EXEC (@TruncLog) 1=W>zC
-- Wrap the log if necessary. c_HYB/'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired W#-M|
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) F-UY~i8
AND (@OriginalSize * 8 /1024) > @NewSize jDy
BEGIN -- Outer loop. .VTHZvyn
SELECT @Counter = 0 _2U1$0xK
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) |/YT.c%
BEGIN -- update FkKx~I:
INSERT DummyTrans VALUES ('Fill Log') V&)-u(s_S/
DELETE DummyTrans ]U'KYrh
SELECT @Counter = @Counter + 1 DQKhR sC
END LD]XN'?"W
EXEC (@TruncLog) J&{E
END Ur]5AJ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + tw\/1wa.
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + olQ;XTa01F
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' k\zN h<^
FROM sysfiles >E[cl\5$E
WHERE name = @LogicalFileName Eh8.S)E
DROP TABLE DummyTrans j
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SET NOCOUNT OFF v3.JG]zLpP
8、说明:更改某个表 TpZ)v.w~l7
exec sp_changeobjectowner 'tablename','dbo' Tx],-
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9、存储更改全部表 u=RF6V|
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch jJ|O]v$N
@OldOwner as NVARCHAR(128), Q]IpHNt[>
@NewOwner as NVARCHAR(128) e@=Bl-
AS }
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DECLARE @Name as NVARCHAR(128) kAf2g
DECLARE @Owner as NVARCHAR(128) )6IO)P/Q~
DECLARE @OwnerName as NVARCHAR(128) }$81FSKh
DECLARE curObject CURSOR FOR )P\ec
select 'Name' = name, S%g`X
'Owner' = user_name(uid) '0/t |V<
from sysobjects 8[2^`g
where user_name(uid)=@OldOwner DkQy.
order by name :|N5fkhN
OPEN curObject A4 o'EQ?~
FETCH NEXT FROM curObject INTO @Name, @Owner LUw0MW(Moi
WHILE(@@FETCH_STATUS=0) ~{RXc+
BEGIN L[Tr"BW
if @Owner=@OldOwner ?w /tq!
begin SP5/K3t-*
set @OwnerName = @OldOwner + '.' + rtrim(@Name) /R 2:Js
exec sp_changeobjectowner @OwnerName, @NewOwner u@[D*c1!H
end vKol@7%N
-- select @name,@NewOwner,@OldOwner a&wl-
FETCH NEXT FROM curObject INTO @Name, @Owner n uhKM.a{
END &kYg
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close curObject #RZW)Br
deallocate curObject ),dXaP[
GO R279=sO,J
10、SQL SERVER中直接循环写入数据 v\0[B jhL?
declare @i int W[w8@OCNf
set @i=1 5A:b
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while @i<30 1r|'n aiZ
begin oT%~)g
insert into test (userid) values(@i) Pou`PNvH
set @i=@i+1 ]"{K5s7
end iS=}| 8"
小记存储过程中经常用到的本周,本月,本年函数 4CfPa6_
Dateadd(wk,datediff(wk,0,getdate()),-1) }(20MW8rMc
Dateadd(wk,datediff(wk,0,getdate()),6) |V%Qp5 XJ
Dateadd(mm,datediff(mm,0,getdate()),0) $(.[b][S
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ZU7,=B=
Dateadd(yy,datediff(yy,0,getdate()),0) MU%C_d%.
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 9m%[
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上面的SQL代码只是一个时间段 J=|fxR
Dateadd(wk,datediff(wk,0,getdate()),-1) C!%BW%"R
Dateadd(wk,datediff(wk,0,getdate()),6) e ST8>r
就是表示本周时间段. }_:^&cT
下面的SQL的条件部分,就是查询时间段在本周范围内的: IGOqV>;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) iK= {pd
而在存储过程中 3dQV5E.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) s?7g3H5#0k
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) f9X*bEl9;`