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。 )I&.6l!#
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一、基础 4fsd5#
1、说明:创建数据库 C7S\4rDJ
CREATE DATABASE database-name I4"p]>Y"
2、说明:删除数据库 ai-s9r'MI?
drop database dbname 3`cA!ZVQ
3、说明:备份sql server 5;}W=x^$a
--- 创建 备份数据的 device /:F^*]
USE master Wa|V~PL+T
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' jae9!Wi
--- 开始 备份 rD=D.1_
BACKUP DATABASE pubs TO testBack 5Rl\& G\
4、说明:创建新表 (|BY<Ac3
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) c9nR&m8(+
根据已有的表创建新表: esJ7#Gxt
A:create table tab_new like tab_old (使用旧表创建新表) cuN ]}=D
B:create table tab_new as select col1,col2... from tab_old definition only dLp1l2h!0
5、说明:删除新表 &MSU<S?1
drop table tabname {[2o
6、说明:增加一个列 #Kb /tOp1
Alter table tabname add column col type m'NAM%$}J
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。 Oin9lg-jR
7、说明:添加主键: Alter table tabname add primary key(col) N;
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说明:删除主键: Alter table tabname drop primary key(col) BI:Cm/ >
8、说明:创建索引:create [unique] index idxname on tabname(col....) gko=5|c,@
删除索引:drop index idxname bKpy?5&>
注:索引是不可更改的,想更改必须删除重新建。 G[mqLI{q
9、说明:创建视图:create view viewname as select statement W,@F!8
删除视图:drop view viewname V8/d27\
10、说明:几个简单的基本的sql语句 m,Y/ke\
选择:select * from table1 where 范围 kumV|$Y?kA
插入:insert into table1(field1,field2) values(value1,value2) kxhsDD$@p
删除:delete from table1 where 范围 1w=.vj<d8
更新:update table1 set field1=value1 where 范围 B!/kC)bF:
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! D<J'\mo
排序:select * from table1 order by field1,field2 [desc] kK=VG<
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总数:select count as totalcount from table1 $YX{gk>
求和:select sum(field1) as sumvalue from table1 <uuumi-!%G
平均:select avg(field1) as avgvalue from table1 sYS
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最大:select max(field1) as maxvalue from table1 X_2N9$},
最小:select min(field1) as minvalue from table1
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11、说明:几个高级查询运算词 */e$S[5
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A: UNION 运算符 dCoP
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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。 9Rk(q4.OP
B: EXCEPT 运算符 >.qFhO\1so
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。 iLnW5yy
C: INTERSECT 运算符 i?/Q7D<P
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。 ^^v3iCT
注:使用运算词的几个查询结果行必须是一致的。 J,Ki2'=
12、说明:使用外连接 50MM05aC
A、left outer join: @m5J%8>k
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。 WVeNO,?ytS
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 !kSemDC
B:right outer join: fJ/INL
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。 E.*hY+kGZ
C:full outer join: vt5w(}v(
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。 wG)e8,#
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二、提升 c
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) yc*cT%?g
法一:select * into b from a where 1<>1 9CS"s_
法二:select top 0 * into b from a *B3f ry
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ?c?@j}=?yY
insert into b(a, b, c) select d,e,f from b; qR.FjQOvn
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) ^P9mJ:
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 k\O<pG[U
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Kk},
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4、说明:子查询(表名1:a 表名2:b) ahXcQ9jzFi
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) KRxJ2
5、说明:显示文章、提交人和最后回复时间 G|jHic!
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b >l 0aME@-0
6、说明:外连接查询(表名1:a 表名2:b) (/uN+
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H}r]j\
7、说明:在线视图查询(表名1:a ) h>bjG
select * from (SELECT a,b,c FROM a) T where t.a > 1; 2;sTSGDG
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 d[?RL&hJO
select * from table1 where time between time1 and time2 4vL\t
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select a,b,c, from table1 where a not between 数值1 and 数值2 O + aK#eF
9、说明:in 的使用方法 qVh?%c1.Y
select * from table1 where a [not] in ('值1','值2','值4','值6') MX]#|hEeQ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Lz1KDXr`)+
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _t-6m2A
11、说明:四表联查问题: 3YLK?X8
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 ..... P1OYS\
12、说明:日程安排提前五分钟提醒 drAJ-ii
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 !!L'{beF
13、说明:一条sql 语句搞定数据库分页 h.?<(I
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 jlb8<xIC]
14、说明:前10条记录 _i ztQ78
select top 10 * form table1 where 范围 p8 S~`fjV
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.) 0i}.l\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) bDDP:INm.
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 Y"t|0dO%b
(select a from tableA ) except (select a from tableB) except (select a from tableC) dXDyY
17、说明:随机取出10条数据 q2xAx1R`sV
select top 10 * from tablename order by newid() iY`[dsT
18、说明:随机选择记录 #q:j~4)h
select newid() eY`z\I
19、说明:删除重复记录 EJ
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) pImq<Z
20、说明:列出数据库里所有的表名 U`)
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select name from sysobjects where type='U' s>L-0vG
21、说明:列出表里的所有的 d1#lC*.Sg
select name from syscolumns where id=object_id('TableName') cWnEp';.
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。 y3(~8n
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 rWWpP<
显示结果: "zw{m+7f,
type vender pcs ]iTP5~8U
电脑 A 1 O)^F z:
电脑 A 1 kR1
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光盘 B 2 ]foS.D,
光盘 A 2 ,sj(g/hg
手机 B 3 c
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手机 C 3 )PR`irw
23、说明:初始化表table1 1?)h-aN
TRUNCATE TABLE table1 %ly&~&0
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc R}(Rv3>Xx
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三、技巧 I.t)sf,
1、1=1,1=2的使用,在SQL语句组合时用的较多 DBy%"/c
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ,MHK|8!
如: 1WaQWZ:=
if @strWhere !='' dgQ<>+9]6
begin @RB^m(> 5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere !gyW15z'
end '~yxu$aK
else O\q6T7bfRW
begin 6GAEQ]
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Y, Lpv|
end WTD86A
我们可以直接写成 y+^KVEw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %a8e_
2、收缩数据库 SIM>Lz
--重建索引 V,zFHXO
DBCC REINDEX ~9YEb
DBCC INDEXDEFRAG cC9Zc#aK
--收缩数据和日志 86KK Y2
DBCC SHRINKDB %*q^i}5)E
DBCC SHRINKFILE OtAAzc!dQ
3、压缩数据库
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dbcc shrinkdatabase(dbname) j<WsFVS
4、转移数据库给新用户以已存在用户权限 Md9y:)P@Y
exec sp_change_users_login 'update_one','newname','oldname' ;<o?JM
go @@3NSKA
5、检查备份集 B !x6N"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' BQ,749^S
6、修复数据库 f^}n#
ALTER DATABASE [dvbbs] SET SINGLE_USER 4<<eqxI$|
GO Wf?[GO
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?W dY{;&
GO KWYjN
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ALTER DATABASE [dvbbs] SET MULTI_USER 3it*l-i\
GO ,y0 &E8Z
7、日志清除 kxrYA|x
SET NOCOUNT ON SPe%9J+
DECLARE @LogicalFileName sysname, cAx$W6S
@MaxMinutes INT, ,ZYPffu<*
@NewSize INT }] 1C=~lC
USE tablename -- 要操作的数据库名 `)8SIx
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 |BtFT
@MaxMinutes = 10, -- Limit on time allowed to wrap log. jc32s}/H
@NewSize = 1 -- 你想设定的日志文件的大小(M) +u |SX/C
-- Setup / initialize lP4s"8E`h
DECLARE @OriginalSize int Rm_+kp@\
SELECT @OriginalSize = size &D|+tu{
FROM sysfiles 1LSD,t|
WHERE name = @LogicalFileName ,9KnC=_y
SELECT 'Original Size of ' + db_name() + ' LOG is ' + $qpW?<>,0
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + lQgavP W!
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 2.{zfr
FROM sysfiles vytO8m%U
WHERE name = @LogicalFileName 7#&Q-3\:
CREATE TABLE DummyTrans y9T5
(DummyColumn char (8000) not null) f6(1jx"
DECLARE @Counter INT, .2|(!a9W
@StartTime DATETIME, 1TzwXX7
@TruncLog VARCHAR(255) $PlMyLu7jc
SELECT @StartTime = GETDATE(), ;xFB
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' /A>nsN?:]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) av'[k<
EXEC (@TruncLog) #
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-- Wrap the log if necessary. Q"!GdKM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired lkp$rJ#6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) `.~*pT*u
AND (@OriginalSize * 8 /1024) > @NewSize zDm3$P=
BEGIN -- Outer loop. K4RQ{fWpm
SELECT @Counter = 0 qm9=Ga5
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) D#,A_GA{A
BEGIN -- update EpT^r8I
INSERT DummyTrans VALUES ('Fill Log') 8B "^}y\0
DELETE DummyTrans &\ad.O/Q
SELECT @Counter = @Counter + 1 U.Z5;E0:
END 3C;;z
EXEC (@TruncLog) 6xr%xk2E
END z t
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ;S&anC#E
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 2H] 7 =j
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' FUL'=Xo
FROM sysfiles ^P.U_2&
WHERE name = @LogicalFileName |<8Fa%!HHc
DROP TABLE DummyTrans VV[Fb9W ;
SET NOCOUNT OFF *6}'bdQbNP
8、说明:更改某个表 fG8^ |:
exec sp_changeobjectowner 'tablename','dbo' S s+
9、存储更改全部表 t,A=B(W
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g^#,!e
@OldOwner as NVARCHAR(128), J_<6;#
@NewOwner as NVARCHAR(128) X_3hh} =
AS oZL# *Z(h
DECLARE @Name as NVARCHAR(128) "ChJR[4@
DECLARE @Owner as NVARCHAR(128) lQRtsmZ0
DECLARE @OwnerName as NVARCHAR(128) 6@:<62!;
DECLARE curObject CURSOR FOR D)[(
select 'Name' = name, pOB<Bx5t
'Owner' = user_name(uid) K|D1
from sysobjects ^@Qc!(P
where user_name(uid)=@OldOwner W%MS,zkAE
order by name +T,0,^*
OPEN curObject LOwd mj
FETCH NEXT FROM curObject INTO @Name, @Owner 3<1x>e2nT
WHILE(@@FETCH_STATUS=0) L|'B*
BEGIN 05jjLM'e
if @Owner=@OldOwner zG%'Cw)8
begin bx-:aC)]2
set @OwnerName = @OldOwner + '.' + rtrim(@Name) _$ 8:\[J
exec sp_changeobjectowner @OwnerName, @NewOwner z63y8
end ra@CouR^c{
-- select @name,@NewOwner,@OldOwner s=K?-O
FETCH NEXT FROM curObject INTO @Name, @Owner u{sb^cmy
END 8RVRfy,w
close curObject jnM}N:v
deallocate curObject \nTV;@F
GO YKOj
10、SQL SERVER中直接循环写入数据 SUvrOl
declare @i int yKz%-6cpSl
set @i=1 YPKB4p#
while @i<30 <1QXZfQ"
begin ]{t!J^Xn
insert into test (userid) values(@i) =?\%E[j
set @i=@i+1 Le/}xST@
end S
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小记存储过程中经常用到的本周,本月,本年函数 PH^Gjm
Dateadd(wk,datediff(wk,0,getdate()),-1) =<K6gC27
Dateadd(wk,datediff(wk,0,getdate()),6) 6 =G=4{q
Dateadd(mm,datediff(mm,0,getdate()),0) pWH,nn?w.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) i
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Dateadd(yy,datediff(yy,0,getdate()),0) $e uI
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) N9rAosO*
上面的SQL代码只是一个时间段 43O5|8o
Dateadd(wk,datediff(wk,0,getdate()),-1) =)w#?DGpj
Dateadd(wk,datediff(wk,0,getdate()),6) 8L6b:$Y3@C
就是表示本周时间段. .2ZFJ.Z"
下面的SQL的条件部分,就是查询时间段在本周范围内的: }EJ/H3<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) W u$yB!
而在存储过程中 )ac!@slb^7
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) >
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) jmP;(j.|