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。 ]k~Vh[[
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一、基础 OjO$.ecT
1、说明:创建数据库 k.=67L
CREATE DATABASE database-name yZkHBG4
2、说明:删除数据库 9QE|p
drop database dbname $Lg%CY
3、说明:备份sql server !_0kn6S5
--- 创建 备份数据的 device %. ^8&4$+
USE master 0s )B~
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' D>"U0*h
--- 开始 备份 ~3-2Iu^F
BACKUP DATABASE pubs TO testBack \|^fG9M~
4、说明:创建新表 v\7k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) AdBF$nn[
根据已有的表创建新表: ER,,K._?B
A:create table tab_new like tab_old (使用旧表创建新表) kB_u U !G
B:create table tab_new as select col1,col2... from tab_old definition only xHEkmL`)4
5、说明:删除新表 3&i8C,u]/O
drop table tabname Cw;&{jY
6、说明:增加一个列 S~^0
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Alter table tabname add column col type ]}z;!D>
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 uV1H iv-
7、说明:添加主键: Alter table tabname add primary key(col) K^z-G=|N
说明:删除主键: Alter table tabname drop primary key(col) N_S>%Z+
8、说明:创建索引:create [unique] index idxname on tabname(col....) pl62mp!
删除索引:drop index idxname `L0aQ$'>z
注:索引是不可更改的,想更改必须删除重新建。 /E>z8J$
9、说明:创建视图:create view viewname as select statement %4QCUc*lr
删除视图:drop view viewname ,])@?TJb@
10、说明:几个简单的基本的sql语句 xR+=F1y
选择:select * from table1 where 范围 ?m-kpW8
插入:insert into table1(field1,field2) values(value1,value2) *]G&pmMs
删除:delete from table1 where 范围 mY"DYYR>
更新:update table1 set field1=value1 where 范围 tV2SX7N
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! i(.c<e{v~
排序:select * from table1 order by field1,field2 [desc] t6
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总数:select count as totalcount from table1 8>q:Q<BB2
求和:select sum(field1) as sumvalue from table1 ^9T6Ix{=
平均:select avg(field1) as avgvalue from table1 a(CZGIB
最大:select max(field1) as maxvalue from table1 it!i'lG
最小:select min(field1) as minvalue from table1 zSta!]
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11、说明:几个高级查询运算词 DJgk"'
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A: UNION 运算符 #|^7{TN
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。 (zkh`8L
B: EXCEPT 运算符 I%xrDiK97
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。 r$ue1bH}|
C: INTERSECT 运算符 e2w$":6>
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。 HN>eS Y+
注:使用运算词的几个查询结果行必须是一致的。 N^|r.J
12、说明:使用外连接 cqeId&Cg
A、left outer join: &rj6<b1A
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。 qS{lay
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 #f]R:Ix>
B:right outer join: (\FjbY9&
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。 bTC2Ya
C:full outer join: "hz(A.THi
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。 ia|^>V>-
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二、提升 g=; rM8W
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) yZI4%fen
法一:select * into b from a where 1<>1 >rlQY>5pH
法二:select top 0 * into b from a tjk Y[
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) z2t;!]"'l
insert into b(a, b, c) select d,e,f from b; rBs7,h
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) W"Dj+/uS
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 #Q6wv/"Ub
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. heZ)+}U~
4、说明:子查询(表名1:a 表名2:b) Wf_aEW&n
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) #c4LdZu9
5、说明:显示文章、提交人和最后回复时间 If6wkY6sR
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b (d993~|h
6、说明:外连接查询(表名1:a 表名2:b) .^#{rk
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c G%ycAm
7、说明:在线视图查询(表名1:a ) LYh5f#
select * from (SELECT a,b,c FROM a) T where t.a > 1; M@!Gk
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 O|,+@qtH
select * from table1 where time between time1 and time2 )ACa0V>*p
select a,b,c, from table1 where a not between 数值1 and 数值2 A4';((OXy
9、说明:in 的使用方法 z1!ya#,$
select * from table1 where a [not] in ('值1','值2','值4','值6') UE7P =B
10、说明:两张关联表,删除主表中已经在副表中没有的信息 L3q)j\ls
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) psRm*,*O
11、说明:四表联查问题: \,
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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 ..... f]T1:N*t
12、说明:日程安排提前五分钟提醒 !QVd'e
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 sLbz@5 4
13、说明:一条sql 语句搞定数据库分页 i )3Y\u
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 pRc(>P3;
14、说明:前10条记录 * VW\
select top 10 * form table1 where 范围 IvIBf2D;Q
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.) tP!sOvQ:
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 3}g?d/^E3
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#AY+
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(select a from tableA ) except (select a from tableB) except (select a from tableC) yF0,}
17、说明:随机取出10条数据 JPQ02&e
select top 10 * from tablename order by newid() +Q-~~v7,
18、说明:随机选择记录 @{I55EQ]
select newid() .U5+PQN
19、说明:删除重复记录 f+xGf6V
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) @T/C<- /:
20、说明:列出数据库里所有的表名 I4|p;\`fK
select name from sysobjects where type='U' 9U}EVpD
21、说明:列出表里的所有的 |w~zh6~
select name from syscolumns where id=object_id('TableName') vo71T<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。
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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 3pDZ}{ZZU
显示结果: nj7Ri=lyS
type vender pcs ,7%(Jj$
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电脑 A 1 njUM>E,'
电脑 A 1 T82=R@7
光盘 B 2 7KM!\"PM
光盘 A 2 kIWQ`)'
手机 B 3 b:O4d<+%
手机 C 3 BM&'3K_y
23、说明:初始化表table1 Ds}6{']K
TRUNCATE TABLE table1 8#Z$}?W
24、说明:选择从10到15的记录 ,+'f unH
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 6@F Z,e
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三、技巧 ?q,x?`|(8
1、1=1,1=2的使用,在SQL语句组合时用的较多 ~Q%QA._R?
"where 1=1" 是表示选择全部 "where 1=2"全部不选, "R9kF-
如: -5>g 0o2
if @strWhere !='' &H+<uYV
begin W\KZFrV@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ]iNSa{G
end
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else ,*lK4?v
begin 5cE[s<=
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' /:USpuu
end O-'T*M>
我们可以直接写成 cxv)LOl-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere jgMWjM6.
2、收缩数据库 9a4RW}S<
--重建索引 \@F{Q-
DBCC REINDEX _9gn;F
DBCC INDEXDEFRAG (f.A5~e
--收缩数据和日志 X0P$r6 ;
DBCC SHRINKDB ePY K^D
DBCC SHRINKFILE m76]INq
3、压缩数据库 q{5Vq_s\
dbcc shrinkdatabase(dbname) j68Gz5;j
4、转移数据库给新用户以已存在用户权限 Anm5Cvt;i
exec sp_change_users_login 'update_one','newname','oldname' i*; V4zh
go _j2`#|oG
5、检查备份集 gSv<.fD"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' dW5z0VuB$/
6、修复数据库 Pb`sn5;
ALTER DATABASE [dvbbs] SET SINGLE_USER EPg?jKZava
GO M<L<mP}
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK _HL3XT
GO x-QP+M`Pu
ALTER DATABASE [dvbbs] SET MULTI_USER DxD0iJ=W
GO tsa6: D
7、日志清除 GkO6r'MVE
SET NOCOUNT ON JjCf<ktE.
DECLARE @LogicalFileName sysname, x~z 2l#ow
@MaxMinutes INT, ";xEuX
@NewSize INT hPH7(f|c{g
USE tablename -- 要操作的数据库名 d^Wh-U
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 JU6np 4
@MaxMinutes = 10, -- Limit on time allowed to wrap log. %2+]3h>g
@NewSize = 1 -- 你想设定的日志文件的大小(M) OH(+]%B78
-- Setup / initialize GhT7:_r~
DECLARE @OriginalSize int O*PHo_&G
SELECT @OriginalSize = size ;wF|.^_2
FROM sysfiles 7wnzef?)
WHERE name = @LogicalFileName /l`XJs
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {+EPE2X=C
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + utE:HD.PN
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' .G]# _U
FROM sysfiles GwycSb1
WHERE name = @LogicalFileName !L_ SHlU
CREATE TABLE DummyTrans ; n@C(hG
(DummyColumn char (8000) not null) &|4Uo5qS=Z
DECLARE @Counter INT, nXS%>1o,
@StartTime DATETIME, pSP_cYa#(#
@TruncLog VARCHAR(255) 00p 7sZU^
SELECT @StartTime = GETDATE(), f#t^<`7
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' {|%O)fr,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ]4yvTP3[Rm
EXEC (@TruncLog) yM2&cMHH~
-- Wrap the log if necessary. 5HN<*u%z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired cn0Fz"d
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) M&FuXG%
AND (@OriginalSize * 8 /1024) > @NewSize ~}AP@t*
BEGIN -- Outer loop. H^g<`XEgw
SELECT @Counter = 0 Kd)m"9Cc
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) U!5*V9T~J
BEGIN -- update ni>
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INSERT DummyTrans VALUES ('Fill Log') <&2,G5XA
DELETE DummyTrans ;`B35K
SELECT @Counter = @Counter + 1 t["Df;"O
END \7/_+)0}'
EXEC (@TruncLog) [//f BO
END 8957$g
SELECT 'Final Size of ' + db_name() + ' LOG is ' + OpLSjr
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ;Y^RF?un
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5m42Bqy"
FROM sysfiles 0 l@P]_qq`
WHERE name = @LogicalFileName Z L</
DROP TABLE DummyTrans 6~ `bAe`}
SET NOCOUNT OFF !&lPdEc@T
8、说明:更改某个表 >G2-kL_
exec sp_changeobjectowner 'tablename','dbo' NO^t/(Z
9、存储更改全部表 @W8}N|jek
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch E+zn\v
@OldOwner as NVARCHAR(128), c5e\ckqm^
@NewOwner as NVARCHAR(128) 0)5Sx /5'
AS ?8@*q6~8
DECLARE @Name as NVARCHAR(128) ,d>~='
DECLARE @Owner as NVARCHAR(128) rj~ian
DECLARE @OwnerName as NVARCHAR(128) Pfx71*u,
DECLARE curObject CURSOR FOR _KVB~loT
select 'Name' = name, )`mF.87b&h
'Owner' = user_name(uid) ->I{
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from sysobjects zI! R-Nb
where user_name(uid)=@OldOwner >-lL-%N_
order by name 2TEeP7
OPEN curObject [!?,TGM}^
FETCH NEXT FROM curObject INTO @Name, @Owner J.2]km
WHILE(@@FETCH_STATUS=0) X-#mv|3
BEGIN t[,T}BCy.
if @Owner=@OldOwner 43=-pyp
begin g/Jj]X#r
set @OwnerName = @OldOwner + '.' + rtrim(@Name) YwWTv
exec sp_changeobjectowner @OwnerName, @NewOwner w s>Iyw.u
end [KI`e
-- select @name,@NewOwner,@OldOwner :TYzzl43
FETCH NEXT FROM curObject INTO @Name, @Owner 14 'x-w^~k
END BC{J3<0bf@
close curObject !9 LAXM
deallocate curObject F>kn:I"X)
GO ?>jArzI
10、SQL SERVER中直接循环写入数据 /{MH'
declare @i int s*/ G-
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set @i=1 X /,1]
while @i<30 a~>0JmM+N
begin I+?$4SC
insert into test (userid) values(@i) nQ!#G(_nO
set @i=@i+1 {R!TUQ5
end OGi4m |
小记存储过程中经常用到的本周,本月,本年函数 -_*XhD
Dateadd(wk,datediff(wk,0,getdate()),-1) n[:AV
Dateadd(wk,datediff(wk,0,getdate()),6) k=~pA iRDN
Dateadd(mm,datediff(mm,0,getdate()),0) m\Fb ,
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) X:-bAu}D
Dateadd(yy,datediff(yy,0,getdate()),0) 5YG@[ic
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %%,hR'+|
上面的SQL代码只是一个时间段 UFAMbI
Dateadd(wk,datediff(wk,0,getdate()),-1) p9}c6{Wp
Dateadd(wk,datediff(wk,0,getdate()),6) -5,y
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就是表示本周时间段. MN M>
下面的SQL的条件部分,就是查询时间段在本周范围内的: }%ZG>LG5J
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 5A]LNA4i
而在存储过程中 )tI2?YIR
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 9Glfi@.
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =']};