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。 1@H3!V4
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一、基础 qPpC )6-Q
1、说明:创建数据库 5vL]Y)l
CREATE DATABASE database-name AR?J[e
2、说明:删除数据库 Nvs8t%
drop database dbname "~4ULl<i'
3、说明:备份sql server &Q^M[X
--- 创建 备份数据的 device
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USE master b0i]T?#
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' #{ M$%l>
--- 开始 备份 d;ElqRC&
BACKUP DATABASE pubs TO testBack a`CsL Bv&
4、说明:创建新表 PCs+`
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) k[N46=u
根据已有的表创建新表: 8KD7t&H
A:create table tab_new like tab_old (使用旧表创建新表) +gTnq")wnI
B:create table tab_new as select col1,col2... from tab_old definition only c8gdY`
5、说明:删除新表 A8OV3h6]
drop table tabname S*:b\{[f>
6、说明:增加一个列 Q^8C*ekfg!
Alter table tabname add column col type v"L<{HN
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 2Ni$
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7、说明:添加主键: Alter table tabname add primary key(col) 4ow)vS(
说明:删除主键: Alter table tabname drop primary key(col) "qb3\0O
8、说明:创建索引:create [unique] index idxname on tabname(col....) xv9Z~JwH
删除索引:drop index idxname Xb42R1
注:索引是不可更改的,想更改必须删除重新建。 abtAkf
9、说明:创建视图:create view viewname as select statement @R?S-*o
删除视图:drop view viewname ocy fU=}X
10、说明:几个简单的基本的sql语句 X LPO_tD
选择:select * from table1 where 范围 "!gd)^<e
插入:insert into table1(field1,field2) values(value1,value2) <UG}P \N
删除:delete from table1 where 范围 `I<*R0Qe
更新:update table1 set field1=value1 where 范围 !E> *Mn
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ;y?,myO
排序:select * from table1 order by field1,field2 [desc] \{n]&IjA
总数:select count as totalcount from table1 i
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求和:select sum(field1) as sumvalue from table1 1P4jdp=~
平均:select avg(field1) as avgvalue from table1 >(u =/pp=:
最大:select max(field1) as maxvalue from table1 A%u-6"
最小:select min(field1) as minvalue from table1 GLL,
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11、说明:几个高级查询运算词 CJ&0<Z}{m
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A: UNION 运算符 APuG8
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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。 B[Uvj~g
B: EXCEPT 运算符 :M1S*"&:
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。 G6Z2[Ej1
C: INTERSECT 运算符 eQno]$-\
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 \no[>L]
注:使用运算词的几个查询结果行必须是一致的。 'rU
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12、说明:使用外连接 y-{^L`%Mk
A、left outer join: ]E88zWDY`
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ooByGQ90V:
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )=;0
B:right outer join: on+
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 <r,l
C:full outer join: 4W~pAruwr
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 d)(61
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二、提升 '6fMF#X4F
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) %K
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法一:select * into b from a where 1<>1 {Os$Uui37\
法二:select top 0 * into b from a qp_kILo~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) IC/'<%k
insert into b(a, b, c) select d,e,f from b; t&wtw
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) 3*3WO,9
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Nj qUUkc
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Ta%{Wa\U9z
4、说明:子查询(表名1:a 表名2:b) uE-~7Q(@
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) J-ACV(z=q
5、说明:显示文章、提交人和最后回复时间 Tl %#N"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 'i{kuTv
6、说明:外连接查询(表名1:a 表名2:b) _UYt
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "MKgU[t
7、说明:在线视图查询(表名1:a ) "o`N6@[w^
select * from (SELECT a,b,c FROM a) T where t.a > 1; 8,#v7ns}#
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 ;_,=
select * from table1 where time between time1 and time2 b|wCR%
select a,b,c, from table1 where a not between 数值1 and 数值2 IBC
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9、说明:in 的使用方法 NHUx-IqOX
select * from table1 where a [not] in ('值1','值2','值4','值6') G{i}z^n
10、说明:两张关联表,删除主表中已经在副表中没有的信息 <u*~RYA2
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) V(A6>0s$|
11、说明:四表联查问题:
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select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... E:f0NV3"1
12、说明:日程安排提前五分钟提醒
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 q*\#HC
13、说明:一条sql 语句搞定数据库分页 uv}[MXOP
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 M$
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14、说明:前10条记录 7Nw7a;h
select top 10 * form table1 where 范围 ;-lk#D?n9
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.) gpe^G64c`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) IR?ICXmtx
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>{K2#k
(select a from tableA ) except (select a from tableB) except (select a from tableC) _LFZ 0
17、说明:随机取出10条数据 !!b5vzyve
select top 10 * from tablename order by newid() Ni'vz7j
18、说明:随机选择记录 $xyG0Q.
select newid() lKrD.iYt8
19、说明:删除重复记录 OA_:_%a(
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) LXG,IG
20、说明:列出数据库里所有的表名 Mje6Q
select name from sysobjects where type='U' d3+pS\&IX?
21、说明:列出表里的所有的 ce/Rzid
select name from syscolumns where id=object_id('TableName') bPAp0}{Fu
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 :O{`!&[>L
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type PtCwr)B,
显示结果: -wy$ ?Ha
type vender pcs =K =FzV'_~
电脑 A 1 0iinr:=u
电脑 A 1 AiykIER/
光盘 B 2 ny|ni\6
光盘 A 2 d Ayof=
手机 B 3 !1]72%k[
手机 C 3 [2gK^o&t
23、说明:初始化表table1 p}hOkx4R\
TRUNCATE TABLE table1 h-=3b
24、说明:选择从10到15的记录 =da_zy
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >;dMumX
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三、技巧 z[ B*sbS
1、1=1,1=2的使用,在SQL语句组合时用的较多 GN /]^{D
"where 1=1" 是表示选择全部 "where 1=2"全部不选, PCH&eTKN
如: 0PIC|
if @strWhere !='' p[VBeO^%
begin 6n]fr9f
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere v9(->X'
end 4*g`!~)
else Pdmfn8I]%
begin :[m;#b
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' rJ4O_a5/
end D+]#qS1q
我们可以直接写成 CDQ}C=4
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere AqZ{x9g!
2、收缩数据库 3XYCtp8
--重建索引 Ra}%:
DBCC REINDEX \C5 YVl#
DBCC INDEXDEFRAG D'F=v\P
--收缩数据和日志 f ."bq43(
DBCC SHRINKDB Wjn1W;m&g
DBCC SHRINKFILE >c*}Do{lG
3、压缩数据库 `/#f8R1g
dbcc shrinkdatabase(dbname) B?'`\q)UL
4、转移数据库给新用户以已存在用户权限 nPj%EKdY4
exec sp_change_users_login 'update_one','newname','oldname' 8Gzc3
go INOw0E[
5、检查备份集 a?/GEfd
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' dkt'~
6、修复数据库 Mf
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ALTER DATABASE [dvbbs] SET SINGLE_USER d>*?C!xE
GO 3,+)3,N
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK nR-`;lrF~
GO Mdsn"Y V
ALTER DATABASE [dvbbs] SET MULTI_USER MU4/arXy
GO cJd~UQ<k
7、日志清除 t8DySFT
SET NOCOUNT ON iUJqAi1o
DECLARE @LogicalFileName sysname, :3M2zV
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@MaxMinutes INT, Q3vC^}Dmr
@NewSize INT uV!Ax*'
USE tablename -- 要操作的数据库名 L}*:,&Y/
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 {O9CYP:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 9E4H`[EQ
@NewSize = 1 -- 你想设定的日志文件的大小(M) `=g9Rg/<
-- Setup / initialize wN\%b}pp
DECLARE @OriginalSize int Gkv<)}G
SELECT @OriginalSize = size n#[-1(P
FROM sysfiles k3h,c;
WHERE name = @LogicalFileName 2F[smUL
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 1Y:lFGoe
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB'
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FROM sysfiles q{5wx8_U
WHERE name = @LogicalFileName U~n>k<`sr
CREATE TABLE DummyTrans Veo:G{
(DummyColumn char (8000) not null) (xf_
DECLARE @Counter INT, RO+B/)~0<
@StartTime DATETIME, 19Xc0ez
@TruncLog VARCHAR(255) '^)Ve:K-.
SELECT @StartTime = GETDATE(), w?)v#]<-
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6ziiV_p
DBCC SHRINKFILE (@LogicalFileName, @NewSize) @d]I3?`
EXEC (@TruncLog) sgp5b$2T.
-- Wrap the log if necessary. / PDe<p
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired S
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) rVgz+'rFD[
AND (@OriginalSize * 8 /1024) > @NewSize rxH*h`Xx@
BEGIN -- Outer loop. 3e4; '5q;
SELECT @Counter = 0 p%toD{$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 8d|omqe~P
BEGIN -- update *{8<4CVv
INSERT DummyTrans VALUES ('Fill Log') jX}}^XwX
DELETE DummyTrans <NZ^*]
SELECT @Counter = @Counter + 1 -.-je"E
END 6nqG;z-IXJ
EXEC (@TruncLog) 2\h}6DGx2
END {WQH
SELECT 'Final Size of ' + db_name() + ' LOG is ' + P0NGjS|Z{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _PD RUJ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' F(c~D0
FROM sysfiles ~V&4<=r`
WHERE name = @LogicalFileName ,3l=44*
DROP TABLE DummyTrans Kk#g(YgNz
SET NOCOUNT OFF fmyyQ|]O"
8、说明:更改某个表 ]L#6'|W
exec sp_changeobjectowner 'tablename','dbo' 7?a@i;E<
9、存储更改全部表 #va|&QBZxM
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 35I y\
@OldOwner as NVARCHAR(128), ^j&'2n@9a
@NewOwner as NVARCHAR(128) _9!*laR!2
AS 8 #fzL7
DECLARE @Name as NVARCHAR(128) p?(w! O
DECLARE @Owner as NVARCHAR(128) Y^80@MJ
DECLARE @OwnerName as NVARCHAR(128) ^HYmi\`
DECLARE curObject CURSOR FOR UQ6UZd37
select 'Name' = name, u3)Oj7cX
'Owner' = user_name(uid) ],CJSA!5F
from sysobjects #U45;idp
where user_name(uid)=@OldOwner 'zCJK~x`x
order by name r2A%.bL#
OPEN curObject ,CqJ((
FETCH NEXT FROM curObject INTO @Name, @Owner qOy3D~
WHILE(@@FETCH_STATUS=0) ^*.S7.;2o
BEGIN 9s\(yC8h
if @Owner=@OldOwner V\Oe ]w
begin ^%l~|w
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 0!X;C!v;
exec sp_changeobjectowner @OwnerName, @NewOwner H%N!;Jz=
end par|j]
-- select @name,@NewOwner,@OldOwner gI8r SmH
FETCH NEXT FROM curObject INTO @Name, @Owner &Fo)ea
END PhBdm'
close curObject }%(e`[?1
deallocate curObject 7L~LpB
GO EH))%LY1y
10、SQL SERVER中直接循环写入数据 > w:+nG/r
declare @i int fDyFkhc
set @i=1 bl@0+NiM
while @i<30 59K%bz5t
begin 8m,PsUp7
insert into test (userid) values(@i) qjcy{@ j
set @i=@i+1 H.`>t
end ]-h$CJSY
小记存储过程中经常用到的本周,本月,本年函数 fFP>$
Dateadd(wk,datediff(wk,0,getdate()),-1) T \%{zz_(
Dateadd(wk,datediff(wk,0,getdate()),6) s`"o-w\$>
Dateadd(mm,datediff(mm,0,getdate()),0) [DrG;k ?
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Ei!t#'*D<
Dateadd(yy,datediff(yy,0,getdate()),0) 3C'`c=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) p;Ezmz
上面的SQL代码只是一个时间段 v~^c-]4I
Dateadd(wk,datediff(wk,0,getdate()),-1) .b]
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Dateadd(wk,datediff(wk,0,getdate()),6) W+k`^A|@
就是表示本周时间段. PZ5BtDm
下面的SQL的条件部分,就是查询时间段在本周范围内的: 7tWt3
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8BZTHlUB
而在存储过程中 9F+i+(\,b
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) P|}~=2J
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 2>~{.4PI