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。 ^Q$OzsEk
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一、基础 \BXzmok
1、说明:创建数据库 K -rR)-rI
CREATE DATABASE database-name HN{c)DIm]
2、说明:删除数据库 [c
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drop database dbname UDg's
3、说明:备份sql server uD&B{c+a
--- 创建 备份数据的 device DdgiY9a.
USE master x^f)I|t
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' S v>6:y9?G
--- 开始 备份 UUJQc~=
BACKUP DATABASE pubs TO testBack _]>1(8_N
4、说明:创建新表 sV
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) x.?5-3|d$
根据已有的表创建新表: }p7iv:P=3
A:create table tab_new like tab_old (使用旧表创建新表) (hzN(Dh
B:create table tab_new as select col1,col2... from tab_old definition only a[O6xA%
5、说明:删除新表 $>XeC}"x68
drop table tabname =#b@7Yw:
6、说明:增加一个列 lS.Adl^k
Alter table tabname add column col type \beO5]KS<
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。 vjGQ! xF
7、说明:添加主键: Alter table tabname add primary key(col) :jLL IqhB
说明:删除主键: Alter table tabname drop primary key(col) Dsg>~J'
8、说明:创建索引:create [unique] index idxname on tabname(col....)
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删除索引:drop index idxname M<fhQJ
注:索引是不可更改的,想更改必须删除重新建。 BPba3G9H
9、说明:创建视图:create view viewname as select statement ATNOb
删除视图:drop view viewname JQ&t"`\k
10、说明:几个简单的基本的sql语句 4]y)YNQ(
选择:select * from table1 where 范围 ;Ba%aaHl
插入:insert into table1(field1,field2) values(value1,value2) Z',!LK!
删除:delete from table1 where 范围 KQdIG9O+6
更新:update table1 set field1=value1 where 范围 fGo4&( U
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! B[t^u\Fk
排序:select * from table1 order by field1,field2 [desc] N4!`iS Y
总数:select count as totalcount from table1 |W">&Rb<t#
求和:select sum(field1) as sumvalue from table1 NI >%v
平均:select avg(field1) as avgvalue from table1 SAx9cjj+
最大:select max(field1) as maxvalue from table1 yGZsNd {a&
最小:select min(field1) as minvalue from table1 ,fVD`RR(W?
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11、说明:几个高级查询运算词 &XP(D5lf`B
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A: UNION 运算符 E7fx4kV
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。
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B: EXCEPT 运算符 Sqo+cZ
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。 gE-y`2SU
C: INTERSECT 运算符 +K57. n{
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。 E9HMhUe
注:使用运算词的几个查询结果行必须是一致的。 H",B[
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12、说明:使用外连接 (q>
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A、left outer join: )D)5
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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。 p\6cpf
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 RpHlq
B:right outer join: N%y i4
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。 24mdhT|
C:full outer join: @
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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。 T(4d5 fY
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二、提升 [m
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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) i=8iK#2 h
法一:select * into b from a where 1<>1 XH:*J+$O
法二:select top 0 * into b from a 1gEH~Jmj
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ${+u-Wfau
insert into b(a, b, c) select d,e,f from b; ;SR ESW
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) h6
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 TOYK'|lwM
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. `+JFvn!
4、说明:子查询(表名1:a 表名2:b) QFyL2Xes/
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) G1"iu89d
5、说明:显示文章、提交人和最后回复时间 X|M!Nt0'
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b YeX*IZX8
6、说明:外连接查询(表名1:a 表名2:b) !XA3G`}p6s
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =lXj%V^8N
7、说明:在线视图查询(表名1:a ) "q4tvcK.
select * from (SELECT a,b,c FROM a) T where t.a > 1; h$>F}n
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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 $6QIYF""
select * from table1 where time between time1 and time2 H#-3
select a,b,c, from table1 where a not between 数值1 and 数值2 0ju1>.p
9、说明:in 的使用方法 j)1y v.
select * from table1 where a [not] in ('值1','值2','值4','值6') bm588UQ
10、说明:两张关联表,删除主表中已经在副表中没有的信息 #c!:&9oU
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) tiK?VwaKI
11、说明:四表联查问题: )n/%P4l
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... CU$khz"
12、说明:日程安排提前五分钟提醒 bIKg>U'5d
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `S&a.k
13、说明:一条sql 语句搞定数据库分页 r@r%qkh(.@
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 kH!Z|Ps?R
14、说明:前10条记录 `h}eP[jA
select top 10 * form table1 where 范围 8WP>u8&
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.) ,N/@=As9$
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) k<1yv$/mW
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 O9gq <d
(select a from tableA ) except (select a from tableB) except (select a from tableC) H/8^Fvd
17、说明:随机取出10条数据 :-&|QVH
select top 10 * from tablename order by newid() }ze+ tf
18、说明:随机选择记录 BEZ~<E&0H
select newid() q:{#kv8
19、说明:删除重复记录 w$gvgz
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 4Nm >5*]
20、说明:列出数据库里所有的表名 B`tq*T%
select name from sysobjects where type='U' mDD.D3RS
21、说明:列出表里的所有的 eK8H5YE
select name from syscolumns where id=object_id('TableName') LvG.ocCG
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。 H$6RDMU
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type J )1
显示结果: .^YxhUH,G
type vender pcs 2:+8]b 3i
电脑 A 1 @xG&K{j
电脑 A 1 ycGY5t@K@
光盘 B 2 N_t,n^i9>*
光盘 A 2 :\TMm>%q
手机 B 3 {%jAp11y+O
手机 C 3 ~C-Sr@ a?/
23、说明:初始化表table1 6)HmE[[F
TRUNCATE TABLE table1 GR,2^]<{
24、说明:选择从10到15的记录 <H[w0Z$
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc /iW+<@Mas
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三、技巧 j:9M${~
1、1=1,1=2的使用,在SQL语句组合时用的较多 mq:k|w^6
"where 1=1" 是表示选择全部 "where 1=2"全部不选, dQX-s=XJ
如: I#l}5e5
if @strWhere !='' uH_KOiF
begin OqGp|`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere a[{qb
end [V}vd@*k
else .=y=Fv6X
begin aRd~T6I
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 8jK=A2pTa
end ET*A0rt
我们可以直接写成 h yrPu_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^`H'LD
2、收缩数据库 gt4GN`-k
--重建索引 FlO?E3d
DBCC REINDEX *i#2>=)
DBCC INDEXDEFRAG s5,@=(,
--收缩数据和日志 z zG=!JR
DBCC SHRINKDB BRFsw`c
DBCC SHRINKFILE @kXuC<
3、压缩数据库 +'H[4g`
dbcc shrinkdatabase(dbname) L
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4、转移数据库给新用户以已存在用户权限 }gSoBu
exec sp_change_users_login 'update_one','newname','oldname' o:8ns m
go r#-
5、检查备份集
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' gx\V)8Zr
6、修复数据库 88Pt"[{1
ALTER DATABASE [dvbbs] SET SINGLE_USER ];.5*a%*
GO ]0i[=
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK e\)%<G5
GO 5 nt3gVy
ALTER DATABASE [dvbbs] SET MULTI_USER F6{g{
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GO EeaJUK]z9
7、日志清除 /%YW[oY{V
SET NOCOUNT ON nC:T0OJv
DECLARE @LogicalFileName sysname, "jZZ>\
@MaxMinutes INT, 0+&WIs
@NewSize INT 8~ y!X0Ov!
USE tablename -- 要操作的数据库名 ,7nu;fOT[
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 LcKc#)'EE
@MaxMinutes = 10, -- Limit on time allowed to wrap log. r$<!?Z
@NewSize = 1 -- 你想设定的日志文件的大小(M) +m_.?V6
-- Setup / initialize }3
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DECLARE @OriginalSize int &0 QUObK
SELECT @OriginalSize = size rpk8
FROM sysfiles PpRS4*nR
WHERE name = @LogicalFileName AB=%yM7V*
SELECT 'Original Size of ' + db_name() + ' LOG is ' + XRaGV~
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + RqROl!6
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' j)ic7b
FROM sysfiles ^%oH LsY9
WHERE name = @LogicalFileName dcKpsX
CREATE TABLE DummyTrans VnuG^)S
(DummyColumn char (8000) not null) >A )Sl'
DECLARE @Counter INT, "t2T*'j{
@StartTime DATETIME, c{'Z.mut
@TruncLog VARCHAR(255) k(f),_
SELECT @StartTime = GETDATE(), mbAzn
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' l@4pZkdq
DBCC SHRINKFILE (@LogicalFileName, @NewSize) U" @5R[=F-
EXEC (@TruncLog) D(z#)oDr
-- Wrap the log if necessary. zBm~ J%
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired >$kFYb>~q
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) *gmc6xY
AND (@OriginalSize * 8 /1024) > @NewSize <v ub
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BEGIN -- Outer loop. $y;w@^
SELECT @Counter = 0 ]xf89[;0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) pyf'_
BEGIN -- update Rd(8j+Q?ps
INSERT DummyTrans VALUES ('Fill Log') 7Kym|Zg
DELETE DummyTrans R14&V1 tZ
SELECT @Counter = @Counter + 1 !fs ~ >
END mq{Z
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EXEC (@TruncLog) *wAX&+);
END H:b"Vd"x9
SELECT 'Final Size of ' + db_name() + ' LOG is ' + yXkQ
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + I'D 3~UIf
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !,-'wT<v
FROM sysfiles 9f['TG,"
WHERE name = @LogicalFileName ^uX"04>;
DROP TABLE DummyTrans 4][VK/v+
SET NOCOUNT OFF -0uGzd+m*
8、说明:更改某个表 Zn1((J7
exec sp_changeobjectowner 'tablename','dbo'
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9、存储更改全部表 f$</BND
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch TaF*ZT2
@OldOwner as NVARCHAR(128), 6oKlr,.
@NewOwner as NVARCHAR(128) `-nSH)GBM
AS nUY)LnI
DECLARE @Name as NVARCHAR(128) C\rT'!Uk\Q
DECLARE @Owner as NVARCHAR(128) [YQtX_;w
DECLARE @OwnerName as NVARCHAR(128) 4Zjd g`
DECLARE curObject CURSOR FOR 2C0j.Ib
select 'Name' = name, )YCH>Za
'Owner' = user_name(uid) H/f}tw
from sysobjects y;0Zk~R$
where user_name(uid)=@OldOwner ldG8hK
order by name HH*,Oe
OPEN curObject //G&=i$
FETCH NEXT FROM curObject INTO @Name, @Owner `zs@W
WHILE(@@FETCH_STATUS=0) h*4wi.-
BEGIN ?,v@H$)3_
if @Owner=@OldOwner <)cmI .J3
begin ^=I[uX-3ue
set @OwnerName = @OldOwner + '.' + rtrim(@Name) c5CxR#O
exec sp_changeobjectowner @OwnerName, @NewOwner $IKN7
end 4&]NC2I
-- select @name,@NewOwner,@OldOwner F0m[ls$
FETCH NEXT FROM curObject INTO @Name, @Owner q9zeN:><
END 8}z PDs
close curObject :U1V 2f'l3
deallocate curObject xZAg
GO uxrNkZia
10、SQL SERVER中直接循环写入数据 _#<l -R`
declare @i int PHsM)V+
set @i=1 }k1[Fc|
while @i<30 #.j:P#
begin qyIy xJ
insert into test (userid) values(@i) d76C]R5L
set @i=@i+1 .<P@6Jq
end Xp^>SSt:4
小记存储过程中经常用到的本周,本月,本年函数 I1ibrn
Dateadd(wk,datediff(wk,0,getdate()),-1) -r_ Pp}s
Dateadd(wk,datediff(wk,0,getdate()),6) )P/~{Ci:T&
Dateadd(mm,datediff(mm,0,getdate()),0) -mZ{.\9
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) +c'I7bBr
Dateadd(yy,datediff(yy,0,getdate()),0) 'bef3P9`
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) zpcm`z
上面的SQL代码只是一个时间段 w68VOymD/
Dateadd(wk,datediff(wk,0,getdate()),-1) =2wy;@f
Dateadd(wk,datediff(wk,0,getdate()),6) lce~6}
就是表示本周时间段. U&tR1v'
下面的SQL的条件部分,就是查询时间段在本周范围内的: *u<@_Oa
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) MU_
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而在存储过程中 6dCqS
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) HQ|{!P\/?U
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) HLt;1:b