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。 T"d]QYJS
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一、基础 ;5Sr<W\:;
1、说明:创建数据库 Zc9
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CREATE DATABASE database-name h'-TZXs0e1
2、说明:删除数据库 2|%30i,vV
drop database dbname ;*Z
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3、说明:备份sql server Y5MHd>m
--- 创建 备份数据的 device m'qMcCE
USE master :za!!^
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' {J0^S
--- 开始 备份 !)9zH
BACKUP DATABASE pubs TO testBack (`!|
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4、说明:创建新表 +&?VA!}.
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) iD(K*[;lc
根据已有的表创建新表: NOS5bm&-
A:create table tab_new like tab_old (使用旧表创建新表) @ ~sp:l
B:create table tab_new as select col1,col2... from tab_old definition only >M1/m=a
5、说明:删除新表
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drop table tabname fRa1m?%s
6、说明:增加一个列 ldX]A#d.
Alter table tabname add column col type J)fS2Ni+
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。 Jx>P%>+<j
7、说明:添加主键: Alter table tabname add primary key(col) <m(nZ'Zqz2
说明:删除主键: Alter table tabname drop primary key(col) r\3In-(AT
8、说明:创建索引:create [unique] index idxname on tabname(col....) F}01ikXDb'
删除索引:drop index idxname <aHK{*'3
注:索引是不可更改的,想更改必须删除重新建。 2hu6
9、说明:创建视图:create view viewname as select statement zWY6D4
删除视图:drop view viewname @W @L%<
10、说明:几个简单的基本的sql语句 g{J3Ba
选择:select * from table1 where 范围 B)-S@.u
插入:insert into table1(field1,field2) values(value1,value2) T]vD ,I+
删除:delete from table1 where 范围 5%>U.X?i
更新:update table1 set field1=value1 where 范围 _>`0!mG
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! X&lkA
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排序:select * from table1 order by field1,field2 [desc] ,!Hl@(
总数:select count as totalcount from table1 -%N (X8
求和:select sum(field1) as sumvalue from table1 tRv#%>fj
平均:select avg(field1) as avgvalue from table1 XW#4C*5?d
最大:select max(field1) as maxvalue from table1 []2GN{m
最小:select min(field1) as minvalue from table1 z H \*v'
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11、说明:几个高级查询运算词 +.R-a+y3
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A: UNION 运算符 SUVr&S6Nk
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。 & aLR'*]6
B: EXCEPT 运算符 ji8Rd"S
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。 !.J~`Y'd_
C: INTERSECT 运算符 |(V%(_s
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。 Ml3F\ fAW
注:使用运算词的几个查询结果行必须是一致的。 {Y@[hoHtF
12、说明:使用外连接 >'T%=50YH
A、left outer join: ;I7Z*'5!
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。 GS,pl9#V_
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 ;4_n:XUgo;
B:right outer join: ~J2Q0Jv
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。 )3
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C:full outer join: lR(&Wc\j
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。 )b7mzDp(
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二、提升 ]d[q:N]z
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) +\ySx^vi
法一:select * into b from a where 1<>1 uJO*aA{K
法二:select top 0 * into b from a 2<O8=I _
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) f6"j-IW[z
insert into b(a, b, c) select d,e,f from b; us cR/d
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) E.6\(^g
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }n=NHHtJ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. bk?\=4B:E
4、说明:子查询(表名1:a 表名2:b) VO`A
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) ) )F.|w
5、说明:显示文章、提交人和最后回复时间 :d#NnR0^L
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Kaa*;T![
6、说明:外连接查询(表名1:a 表名2:b) =,'Z6?%p
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8vRiVJ8QS:
7、说明:在线视图查询(表名1:a ) lrE0)B5F
select * from (SELECT a,b,c FROM a) T where t.a > 1; 9j"\Lr*o"
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 Z~|J"2.
select * from table1 where time between time1 and time2 QE gv,J{
select a,b,c, from table1 where a not between 数值1 and 数值2 b?$09,{0
9、说明:in 的使用方法 8j$q%g
select * from table1 where a [not] in ('值1','值2','值4','值6') }cT}G;L'-
10、说明:两张关联表,删除主表中已经在副表中没有的信息 3pp
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 2ya`2 m
11、说明:四表联查问题: *O5+?J Z!
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 ..... Q.\>+4]1&&
12、说明:日程安排提前五分钟提醒 s7e'9Bx
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ayD\b6Z2.
13、说明:一条sql 语句搞定数据库分页 %FU[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 ?MYD}`Cv
14、说明:前10条记录 la4,Z
select top 10 * form table1 where 范围 HA%ye"(y8
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.) GEA;9TU|V
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) M($},xAvDU
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 >
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(select a from tableA ) except (select a from tableB) except (select a from tableC) i/~J0qQ
17、说明:随机取出10条数据 P Cf|^X#B
select top 10 * from tablename order by newid() wl%1B64
18、说明:随机选择记录 LJy'wl
select newid() #dft-23
19、说明:删除重复记录 JK(&E{80
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _:L*{=N
20、说明:列出数据库里所有的表名 K)?^b|D
select name from sysobjects where type='U' ~c^-DAgB
21、说明:列出表里的所有的 h[]N=X
select name from syscolumns where id=object_id('TableName') *LRGfk+h
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。 ^sKXn:)
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 MUrY >FYgx
显示结果: nf4P2<L!
type vender pcs IMZKlU3
电脑 A 1 'dzp@-\
电脑 A 1 07|NPS
光盘 B 2 B<LavX>F
光盘 A 2 ~30Wb9eL
手机 B 3 WFd2_oAT
手机 C 3 I/aAx.q
23、说明:初始化表table1 h 3&:"*A2
TRUNCATE TABLE table1 rieQ&Jt"
24、说明:选择从10到15的记录 ?N
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc |
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三、技巧 &EPEpN
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1、1=1,1=2的使用,在SQL语句组合时用的较多 1Q5<6*QL"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, dx}/#jMa
如: L\ %_<2
if @strWhere !='' xgz87d/<:
begin |^Es6 .~
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 2M?lgh4"
end .;b>
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else uKy *N*}
begin =T)2wcXBB
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ib_Gy77Os
end X6 ,9D[Nw
我们可以直接写成 v8Zgog)V
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere bJm0
2、收缩数据库 ~ ""MeaM8[
--重建索引 3kCbD=yF
DBCC REINDEX Y14R"*t~
DBCC INDEXDEFRAG Wu( 8G
--收缩数据和日志 `tG_O
DBCC SHRINKDB kZ9<j+.
DBCC SHRINKFILE <6C9R>
3、压缩数据库 yk<jlVF$j
dbcc shrinkdatabase(dbname) N o(f0g.
4、转移数据库给新用户以已存在用户权限 2.D!4+&
exec sp_change_users_login 'update_one','newname','oldname' #sU~fq
go _oTT3[7P
5、检查备份集 prN(V1O
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' U.U.\
6、修复数据库 es[5B* 5
ALTER DATABASE [dvbbs] SET SINGLE_USER ^P/D8cXa4
GO b@/ON}gX
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK rx>Tc#g
GO 49oW 'j
ALTER DATABASE [dvbbs] SET MULTI_USER 0>=)
GO #2jn4>
7、日志清除 $
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SET NOCOUNT ON Hi_Al,j:
DECLARE @LogicalFileName sysname, RYl3txw
@MaxMinutes INT, vvAk<[
@NewSize INT NP`s[
USE tablename -- 要操作的数据库名 iBQBHF
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 W \}}gIEM+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 7;'.5,-3c
@NewSize = 1 -- 你想设定的日志文件的大小(M) S7ehk*`
-- Setup / initialize S}^s5ztm
DECLARE @OriginalSize int I~LQ1_
SELECT @OriginalSize = size kA%OF*%|6
FROM sysfiles .k`*$1?73x
WHERE name = @LogicalFileName s2?,' es
SELECT 'Original Size of ' + db_name() + ' LOG is ' + +?Jk@lE<
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + gAA
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' T[h}A"yK;
FROM sysfiles -\'.JA_
WHERE name = @LogicalFileName P}9Y8$Y>U
CREATE TABLE DummyTrans &JhIn%=-
(DummyColumn char (8000) not null) -ouJf}#R
DECLARE @Counter INT, E#$_uZ4
@StartTime DATETIME, pq?[ wp"
@TruncLog VARCHAR(255) rtL9cw5
SELECT @StartTime = GETDATE(), f=_?<I{
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' IHbo w0'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) cm@ oun
EXEC (@TruncLog) 1LE^dS^V
-- Wrap the log if necessary. *OOa)P{^D
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired .8qzU47E
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) EO/cW<uV'
AND (@OriginalSize * 8 /1024) > @NewSize RO$@>vL
BEGIN -- Outer loop. (
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SELECT @Counter = 0 :+
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 8U2wH
BEGIN -- update V> a3V'
INSERT DummyTrans VALUES ('Fill Log') {<}I9D5
DELETE DummyTrans CDW(qq-zD
SELECT @Counter = @Counter + 1 ]2\2/~l
END 39T&c85
EXEC (@TruncLog) 3TiXYH
END |<3Q+EB^
SELECT 'Final Size of ' + db_name() + ' LOG is ' + K;y\[2;}e,
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + b6!Q!:GO&
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' J4Z<Yt/
FROM sysfiles k[ffs}
WHERE name = @LogicalFileName ?Y0$X>nm
DROP TABLE DummyTrans x|v[Dxf]
SET NOCOUNT OFF M,\|V3s
8、说明:更改某个表 )/WA)fWkT
exec sp_changeobjectowner 'tablename','dbo' _UBJPb@=U
9、存储更改全部表 $qlqWy-s
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch p=-B~:
@OldOwner as NVARCHAR(128), ?%dCU~ z
@NewOwner as NVARCHAR(128) bpF@}#fT
AS (#-=y~%
DECLARE @Name as NVARCHAR(128) /[|}rqX(
DECLARE @Owner as NVARCHAR(128) @0UwI%.
DECLARE @OwnerName as NVARCHAR(128) VJl &Bq+
DECLARE curObject CURSOR FOR /2_B$
select 'Name' = name, Sa[EnC
'Owner' = user_name(uid) W-C0YU1
from sysobjects C`)^~C_]`3
where user_name(uid)=@OldOwner N
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order by name P96Cw~<Q?
OPEN curObject `z$uw
FETCH NEXT FROM curObject INTO @Name, @Owner v;bM.OL
WHILE(@@FETCH_STATUS=0) -Ty<9(~S
BEGIN qN1e{T8u
if @Owner=@OldOwner \9>g;qPg}
begin _yxe2[TD
set @OwnerName = @OldOwner + '.' + rtrim(@Name) f`u5\!}=!
exec sp_changeobjectowner @OwnerName, @NewOwner nXM9Px!
end lNh=>DPu
-- select @name,@NewOwner,@OldOwner ]*g ss'N
FETCH NEXT FROM curObject INTO @Name, @Owner A|
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END !8
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close curObject SA`J.4yn
deallocate curObject [I++>4
GO 7dufY
} }
10、SQL SERVER中直接循环写入数据 S&
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declare @i int =p,4=wo{
set @i=1 =0s`4Y"+
while @i<30 *%Nns',
begin <nOuyGIZ
insert into test (userid) values(@i) r?"}@MRW
set @i=@i+1 $LxG>db
end GFQG(7G9
小记存储过程中经常用到的本周,本月,本年函数 ~51kiQW
Dateadd(wk,datediff(wk,0,getdate()),-1) _cxm}*}\#
Dateadd(wk,datediff(wk,0,getdate()),6) %;=IMMK
Dateadd(mm,datediff(mm,0,getdate()),0) Imh2~rw;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) }"&n[/8~
Dateadd(yy,datediff(yy,0,getdate()),0) /\ ,_P
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Io,/ +#|
上面的SQL代码只是一个时间段 kH>vD =q>
Dateadd(wk,datediff(wk,0,getdate()),-1) d6t)gG*5
Dateadd(wk,datediff(wk,0,getdate()),6) H;TOPtt2
就是表示本周时间段. 33{;[/4
下面的SQL的条件部分,就是查询时间段在本周范围内的: qXP1Q3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 7E!";HT
而在存储过程中 [Q7->Wo|S:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) k lP{yxU'n
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) xI`Uk8- 8