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。 R|$[U
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一、基础 ]u;GNz}?
1、说明:创建数据库 90?,-6
CREATE DATABASE database-name Pf{`/UlD
2、说明:删除数据库 u\:rY)V
drop database dbname @c0n2 Xcr
3、说明:备份sql server Tt`L(oF
--- 创建 备份数据的 device H/pcXj
USE master 6hLNJ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' C(xqvK~p
--- 开始 备份 =zz+<!!
BACKUP DATABASE pubs TO testBack db<q-u
4、说明:创建新表 (eki X*y
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) aN:HG)$@
根据已有的表创建新表: yB=C5-\F
A:create table tab_new like tab_old (使用旧表创建新表) v;Swo("
B:create table tab_new as select col1,col2... from tab_old definition only xJN |w\&
5、说明:删除新表 'N*!>mZ<
drop table tabname 0Y[*lM-
6、说明:增加一个列 ~Vwk:+):
Alter table tabname add column col type #>@<n3rq
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。 <Kh?Ad>N
7、说明:添加主键: Alter table tabname add primary key(col) ?_8%h`z
说明:删除主键: Alter table tabname drop primary key(col) y-%nJD$
8、说明:创建索引:create [unique] index idxname on tabname(col....) Xm%iPrl D
删除索引:drop index idxname &|s+KP|d
注:索引是不可更改的,想更改必须删除重新建。 &K+
9、说明:创建视图:create view viewname as select statement ss/h[4h4h
删除视图:drop view viewname DgC3>
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10、说明:几个简单的基本的sql语句 3Ca
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选择:select * from table1 where 范围 c]e`m6
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 Z@;jIH4 (
更新:update table1 set field1=value1 where 范围 \>4v?\8o
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Akv(} !g
排序:select * from table1 order by field1,field2 [desc] /tG 5!l
总数:select count as totalcount from table1 B%TXw#|
求和:select sum(field1) as sumvalue from table1 (QhGxuC
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 C:rRK*
最小:select min(field1) as minvalue from table1 7t ZW^dF
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11、说明:几个高级查询运算词 1XqIPiXJ
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A: UNION 运算符 1d/NZJ9
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。 @bc[
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B: EXCEPT 运算符 >_&~!Y.Z=
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。 O~$ {&(
C: INTERSECT 运算符 J 5Wz4`'
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。 j?Cr31
注:使用运算词的几个查询结果行必须是一致的。 RP,A!pa@
12、说明:使用外连接 c!tvG*{
A、left outer join: /&*m1EN#o
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。 rny@n^F
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 olYPlHF
B:right outer join: XyvZ&d6(d
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。 j|&{e91,?
C:full outer join: V xp$#3 ;S
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 O|HIO&M
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二、提升 7bA4P*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )w
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法一:select * into b from a where 1<>1 ls [Ls
法二:select top 0 * into b from a F9Ifw><XM
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) mGt\7&`
insert into b(a, b, c) select d,e,f from b; [u/zrpTk
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) kyy0&L
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 QpdujtH`
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. bc
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4、说明:子查询(表名1:a 表名2:b) hZp=BM"bJ
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 2=igS#h
5、说明:显示文章、提交人和最后回复时间 `%FIgE^
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b }V\P,ck
6、说明:外连接查询(表名1:a 表名2:b) di8W2cwz
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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7、说明:在线视图查询(表名1:a ) f%bc64N(
select * from (SELECT a,b,c FROM a) T where t.a > 1; DkDw>Nx<rs
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 70'}f
select * from table1 where time between time1 and time2 x?%rx}h
select a,b,c, from table1 where a not between 数值1 and 数值2 :hC
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9、说明:in 的使用方法 v9Z lNA7m!
select * from table1 where a [not] in ('值1','值2','值4','值6') 3C>2x(]M
10、说明:两张关联表,删除主表中已经在副表中没有的信息 HF*j`}
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) B`g<Ge~
11、说明:四表联查问题: {D;Xa`:O
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... fQ=&@ >e
12、说明:日程安排提前五分钟提醒 &Pmc"9Rl
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 s$f+/Hs
13、说明:一条sql 语句搞定数据库分页 >E//pr)_Km
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 cEDDO&u
14、说明:前10条记录 P]!LN\[
select top 10 * form table1 where 范围 ~bQFk?ZN+
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.) j~+[uzW98
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ?R|fS*e2EB
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 )m|X;eEo
(select a from tableA ) except (select a from tableB) except (select a from tableC) =giM@MV
17、说明:随机取出10条数据 /Oq1q._9F
select top 10 * from tablename order by newid() 0MwG}|RC
18、说明:随机选择记录 *4(/t$)pEl
select newid() XX]5T`D
19、说明:删除重复记录 "\VW.S
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) GOv92$e
20、说明:列出数据库里所有的表名 9F2w.(m
select name from sysobjects where type='U' c*y$bf<
21、说明:列出表里的所有的 v+xgxQGYH
select name from syscolumns where id=object_id('TableName') K!IF?iell
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 hKk\Y{wv'
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type * 23m-
显示结果: 1_Dn?G^H
type vender pcs Ov$N"
电脑 A 1 uS!
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电脑 A 1 1$='`@8I
光盘 B 2 a<OCO0irJ
光盘 A 2 ](B&l{V
手机 B 3 uznoyj6g
手机 C 3 .jU|gf:x
23、说明:初始化表table1 Nb^zkg
TRUNCATE TABLE table1 /3)YWFZZc
24、说明:选择从10到15的记录 A2g"=x[1@K
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc }XfS#Xr1aV
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三、技巧 ka?IX9t\
1、1=1,1=2的使用,在SQL语句组合时用的较多 L Q I: ]d
"where 1=1" 是表示选择全部 "where 1=2"全部不选, xm%[}Dt]
如: XBfia j
if @strWhere !='' jjS{q,bo
begin f_i"/xC-/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere `-72>F ;T
end 33#7U+~]@
else gFWEodx,9
begin {Y3_I\H8{
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' &%f ]-=~
end p|bc=`TD
我们可以直接写成 ,<uiitOo
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Pe+ 8~0o=R
2、收缩数据库 U /1[~429
--重建索引 mV:RmA
DBCC REINDEX (ybtXoQs
DBCC INDEXDEFRAG br34Eh
--收缩数据和日志 2FZ0c/[&
DBCC SHRINKDB LyJTK1]#
DBCC SHRINKFILE a@5xz)
3、压缩数据库 AiyvHt
dbcc shrinkdatabase(dbname) f>\bUmk(
4、转移数据库给新用户以已存在用户权限 Vq\..!y
exec sp_change_users_login 'update_one','newname','oldname' U}RS*7`
go Q.pEUDq/
5、检查备份集 b*'=W"%\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' jm#d7@~4
6、修复数据库 _SBp66
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ALTER DATABASE [dvbbs] SET SINGLE_USER H0D>A<Ue
GO 9Sx<tj_4P{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK WTV3p,;6a
GO c-s`>m
ALTER DATABASE [dvbbs] SET MULTI_USER 4! Oa4
GO 1c<CEq:?e%
7、日志清除 66^1&D"
SET NOCOUNT ON c:h.J4mv
DECLARE @LogicalFileName sysname, Ac5o K
@MaxMinutes INT, O?j98H
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@NewSize INT CfkNy[}=
USE tablename -- 要操作的数据库名 eB<V%,%N#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 !OuTXa,IH
@MaxMinutes = 10, -- Limit on time allowed to wrap log. s%L"
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@NewSize = 1 -- 你想设定的日志文件的大小(M) A]tf>H#1
-- Setup / initialize I9:G9
DECLARE @OriginalSize int >?G|Yz*kEJ
SELECT @OriginalSize = size e\d5SKY
FROM sysfiles [5RFQ!
WHERE name = @LogicalFileName we:5gK&
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ? !oVf>
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + /+<%,c$n
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 8}"f|6Wm
FROM sysfiles fncwe ';?
WHERE name = @LogicalFileName |7S4;
CREATE TABLE DummyTrans 7kX7\[zN
(DummyColumn char (8000) not null) 2vh!pez_
DECLARE @Counter INT, JL.ydH79
@StartTime DATETIME, (:fE _H2z
@TruncLog VARCHAR(255) zCGmn& *M
SELECT @StartTime = GETDATE(), 7+D'W7Yx
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' j^aQ>(t(9
DBCC SHRINKFILE (@LogicalFileName, @NewSize) D)O6|DiO
EXEC (@TruncLog) 0'V-
-- Wrap the log if necessary. pE(<XD3Q
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired L6rs9su=7
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {x&jh|f`g
AND (@OriginalSize * 8 /1024) > @NewSize *&hXJJ[+
BEGIN -- Outer loop. &-8-xw#.
SELECT @Counter = 0 ~P]HG;$?n
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -hG 9
BEGIN -- update F)E7(Un`8
INSERT DummyTrans VALUES ('Fill Log') 0'q(XB`i=
DELETE DummyTrans ohc/.5Kl
SELECT @Counter = @Counter + 1 S0Bl?XsD_
END _ntW}})K
EXEC (@TruncLog) I(?|Ox9"?
END ziLr }/tg
SELECT 'Final Size of ' + db_name() + ' LOG is ' + pzt Zb
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + px
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5QL9w3L
FROM sysfiles -aH?7HV}
WHERE name = @LogicalFileName XY+aunLf
DROP TABLE DummyTrans @KW+?maW
SET NOCOUNT OFF _~wV{ yp
8、说明:更改某个表 QN}3S0
exec sp_changeobjectowner 'tablename','dbo' +3o)L?:g
9、存储更改全部表 =qS^Wz.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch {o5K?Pb
@OldOwner as NVARCHAR(128), 9A}
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@NewOwner as NVARCHAR(128) j0pvLZjM
AS :_~PU$%0
DECLARE @Name as NVARCHAR(128) k9_VhR|!
DECLARE @Owner as NVARCHAR(128) ;GSFQ:m[
DECLARE @OwnerName as NVARCHAR(128) #a'x)$2;R|
DECLARE curObject CURSOR FOR [#Nx>RY
select 'Name' = name, n7, 6a
'Owner' = user_name(uid) ~U7\ LBF
from sysobjects :S+U}Sm[
where user_name(uid)=@OldOwner ?^yh5
order by name uu@'02G8
OPEN curObject G8(i).Q
FETCH NEXT FROM curObject INTO @Name, @Owner M;p q2$
WHILE(@@FETCH_STATUS=0) [BZ(p
BEGIN T24#gF~
if @Owner=@OldOwner E?m#S
begin ^zWO[$n}tP
set @OwnerName = @OldOwner + '.' + rtrim(@Name) C>\!'^u1
exec sp_changeobjectowner @OwnerName, @NewOwner QnP?;
end ' ! UF&
-- select @name,@NewOwner,@OldOwner >h!.Gj
FETCH NEXT FROM curObject INTO @Name, @Owner 8v)~J}[ Bz
END t~<-4N$(
close curObject Y^jnlS)h
deallocate curObject S^Wqa:;
GO SG|i/K|7
10、SQL SERVER中直接循环写入数据 yz2oS|0 '
declare @i int R 6yvpH
set @i=1 602eLV)
while @i<30 xZ @O"*{
begin
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insert into test (userid) values(@i) ANpY qV
set @i=@i+1 WlQ&Yau
end Etr8lm E
小记存储过程中经常用到的本周,本月,本年函数 S4:\`Lo-;
Dateadd(wk,datediff(wk,0,getdate()),-1) GaK_9Eg-2
Dateadd(wk,datediff(wk,0,getdate()),6) E]eqvT NH
Dateadd(mm,datediff(mm,0,getdate()),0) %*Z2Gef?H
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) }PIGj} F/
Dateadd(yy,datediff(yy,0,getdate()),0) ik:)-GV;s
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) }rMpp[
上面的SQL代码只是一个时间段 G4exk5
Dateadd(wk,datediff(wk,0,getdate()),-1) Znl>*e/|
Dateadd(wk,datediff(wk,0,getdate()),6) Zz)oMw
就是表示本周时间段. \I,Dje/:w
下面的SQL的条件部分,就是查询时间段在本周范围内的: }Mb'tGW
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Hj4w
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而在存储过程中 x+:,b~Skk
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) hq8/`u
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) zUUxxS_?