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。 Ydrh+
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一、基础 yn!;Z._
1、说明:创建数据库 Zocuc"j
CREATE DATABASE database-name XFoSGqD
2、说明:删除数据库 Y$v d@Q
drop database dbname Xd A]);,
3、说明:备份sql server ykbfK$jz
--- 创建 备份数据的 device T&[6
USE master Y}BP]#1
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' xKE=$SV(
--- 开始 备份 ~9o@1TO:v
BACKUP DATABASE pubs TO testBack _5S0A0
4、说明:创建新表 KC}G_"f.$
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) gnZ#86sO
根据已有的表创建新表: kO}%Y?9d
A:create table tab_new like tab_old (使用旧表创建新表) 1y:fH4V
B:create table tab_new as select col1,col2... from tab_old definition only Fq~Zr;A
5、说明:删除新表 M 0}r)@
drop table tabname ]d(Z%
6、说明:增加一个列 >QYx9`x&
Alter table tabname add column col type VfzyBjQ
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。 ?<.a>"!
7、说明:添加主键: Alter table tabname add primary key(col) %|x9C,0p#
说明:删除主键: Alter table tabname drop primary key(col) xkFa
8、说明:创建索引:create [unique] index idxname on tabname(col....) 8!35
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删除索引:drop index idxname j)8$hK/e0.
注:索引是不可更改的,想更改必须删除重新建。 ">=E p+ix
9、说明:创建视图:create view viewname as select statement ZFMO;'m&
删除视图:drop view viewname mg:kVS
10、说明:几个简单的基本的sql语句 %?n=In(F
选择:select * from table1 where 范围 %|+aI?
插入:insert into table1(field1,field2) values(value1,value2) _YlyS )#@
删除:delete from table1 where 范围 {i=V:$_#
更新:update table1 set field1=value1 where 范围 \y271}'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #f(tzPD
排序:select * from table1 order by field1,field2 [desc] y(<{e~
总数:select count as totalcount from table1 }.D18bE(
求和:select sum(field1) as sumvalue from table1 V?yQm4
平均:select avg(field1) as avgvalue from table1 Kh4rl)L*+%
最大:select max(field1) as maxvalue from table1 #@-dT,t
最小:select min(field1) as minvalue from table1 $W}:,]hoj
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11、说明:几个高级查询运算词 D8!
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A: UNION 运算符 G)YmaHeI;[
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 - s'W^(
B: EXCEPT 运算符 Q'jGNWep
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 7./-|#
C: INTERSECT 运算符 (D[~Z!
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 i{N?Y0YQs0
注:使用运算词的几个查询结果行必须是一致的。 A-B>VX
12、说明:使用外连接 Ln6emXqw
A、left outer join: "
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 ';\norx;
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c E3p$^['vx
B:right outer join: whe%o
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。 lE%KzX?&
C:full outer join: H/`@6, j
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。 A-m IWTa
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二、提升 ~pH!.|k-&
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Ys_LGfK
法一:select * into b from a where 1<>1 o1\N)%
法二:select top 0 * into b from a }s?w-u+(c6
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) D]fgBW-
insert into b(a, b, c) select d,e,f from b; .nEMd/pX
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) Ar~<l2,{r
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 4 5wqX h
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _~tF2`,Y_p
4、说明:子查询(表名1:a 表名2:b) dpchZ{
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) fup?Mg-
5、说明:显示文章、提交人和最后回复时间 \kKd:C{
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b z|],s]F>G
6、说明:外连接查询(表名1:a 表名2:b) -]}#Z:&
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c lmUCrs37
7、说明:在线视图查询(表名1:a ) 5`&@3
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select * from (SELECT a,b,c FROM a) T where t.a > 1; 4`o0?_.'
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 \;_tXb}F
select * from table1 where time between time1 and time2 L;g2ZoqIr0
select a,b,c, from table1 where a not between 数值1 and 数值2 ^-Arfm%dn
9、说明:in 的使用方法 #a@ jt
select * from table1 where a [not] in ('值1','值2','值4','值6') W,,3@:
10、说明:两张关联表,删除主表中已经在副表中没有的信息 m4uh<;C~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) R-W.$-rF
11、说明:四表联查问题: r/':^Ex
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... _IEbRVpb
12、说明:日程安排提前五分钟提醒 ~x4]p|)</
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^^
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13、说明:一条sql 语句搞定数据库分页 ^o>WCU =
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 Z$c&Y>@)
14、说明:前10条记录 /g%RIzgW
select top 10 * form table1 where 范围 _7u&.l<;
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.) E}%Pwr
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )gU:Up24|"
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
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(select a from tableA ) except (select a from tableB) except (select a from tableC) _qOynW
17、说明:随机取出10条数据 H/ e jO_{
select top 10 * from tablename order by newid() }jce5E
18、说明:随机选择记录 ^wSGrV'
select newid() -/B*\X[
19、说明:删除重复记录 {C?$osrr
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) jC:D>
20、说明:列出数据库里所有的表名 N0$
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select name from sysobjects where type='U' z*b|N45O
21、说明:列出表里的所有的 wZCboQ,
select name from syscolumns where id=object_id('TableName') #~m^RoE
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。 Exv!!0Cd^
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 iu{;|E
显示结果: VR_/Vh]@
type vender pcs i&m6;>?`
电脑 A 1 v`'Iew }
电脑 A 1 h(~of(
光盘 B 2 4/\Ynb.L
光盘 A 2 }h/7M
手机 B 3 Ap"%%D^{:
手机 C 3 Q;y4yJ$wI
23、说明:初始化表table1 5>e<|@2
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TRUNCATE TABLE table1 YsiH=x
24、说明:选择从10到15的记录 dKXzFyW
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc #/9Y}2G|]
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三、技巧 v^t oe
1、1=1,1=2的使用,在SQL语句组合时用的较多 RxV
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, w .M
如: i*4v!(E
if @strWhere !='' e50xcf1u
begin 8eh3K8tL#
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere yO\bVu5V
end tqB6:p-%
else /IX555/dR1
begin (?7}\B\
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' -y_q
end 6r%i=z
我们可以直接写成 3*7 klu
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere e8_EB/)_Z
2、收缩数据库 M
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--重建索引 m,6u+Z,
DBCC REINDEX .A/xH
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DBCC INDEXDEFRAG 8{icY|:MTN
--收缩数据和日志 .DnG}884
DBCC SHRINKDB cFjD*r-
DBCC SHRINKFILE zw5Ol%JF
3、压缩数据库 A'u]z\&%c
dbcc shrinkdatabase(dbname) /{[tU-}qJ
4、转移数据库给新用户以已存在用户权限 hCX/k<}I
exec sp_change_users_login 'update_one','newname','oldname' ?mVSc/
go u]9 #d^%V
5、检查备份集 ]H`pM9rC
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' w!d(NA<|0]
6、修复数据库 !w!k0z]
ALTER DATABASE [dvbbs] SET SINGLE_USER S;#7B?j
GO !-SI &qy
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ?caHS2%?ae
GO *cXi*7|=
ALTER DATABASE [dvbbs] SET MULTI_USER K-c>J
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GO l8%BRG
7、日志清除 0,#n_"
SET NOCOUNT ON a>Aq/=
DECLARE @LogicalFileName sysname, weGsjy(b]N
@MaxMinutes INT, .UN?Ak*R
@NewSize INT Gp?pSI,b.t
USE tablename -- 要操作的数据库名 B'y)bY'_dS
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 :UKc:JVNM
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 6 RSit
@NewSize = 1 -- 你想设定的日志文件的大小(M) lF7".
-- Setup / initialize NUh%\{
DECLARE @OriginalSize int NP!LBB)=Y
SELECT @OriginalSize = size bVZAf
FROM sysfiles Crla~h?=
WHERE name = @LogicalFileName i_!$bk<yo
SELECT 'Original Size of ' + db_name() + ' LOG is ' + .M[t5I'\
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + xA*6Z)Y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' AS4oz:B
FROM sysfiles )T
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WHERE name = @LogicalFileName v`qXb$YW
CREATE TABLE DummyTrans 5VVU%STP
(DummyColumn char (8000) not null) >B$ IrM7J
DECLARE @Counter INT, I&&;a.
@StartTime DATETIME, MQ'=qR
@TruncLog VARCHAR(255) $.ctlWS8l{
SELECT @StartTime = GETDATE(), [ 'B u
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]h`d>#Hw!
DBCC SHRINKFILE (@LogicalFileName, @NewSize) VhnIr#L+
EXEC (@TruncLog) {?cF2K#
-- Wrap the log if necessary. x'Nc}
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired RO[X#c
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {?mb.~(
AND (@OriginalSize * 8 /1024) > @NewSize QPFv]^s(
BEGIN -- Outer loop. ?l|&JgJ$
SELECT @Counter = 0 v(uNqX.BC
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) @y
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BEGIN -- update \^'-=8<*>
INSERT DummyTrans VALUES ('Fill Log') t`eIkq|NxI
DELETE DummyTrans T$DFTr\\
SELECT @Counter = @Counter + 1 :;]O;RXt
END r'*#i>PkQD
EXEC (@TruncLog) Oo~
END [*H h6
SELECT 'Final Size of ' + db_name() + ' LOG is ' + g\49[U}[~F
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + SHnMqaq
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' tC/+
FROM sysfiles )2jH&}K
WHERE name = @LogicalFileName wr>6Go%
DROP TABLE DummyTrans 'OU3-K
SET NOCOUNT OFF :$XlYJrjK
8、说明:更改某个表 -<u_fv
exec sp_changeobjectowner 'tablename','dbo' gEgd/Le
9、存储更改全部表 5RF*c,cNq
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch BISH34
@OldOwner as NVARCHAR(128), =""5
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@NewOwner as NVARCHAR(128) szOa yAS
AS g`6I, 6G
DECLARE @Name as NVARCHAR(128) z4]z3U<}3]
DECLARE @Owner as NVARCHAR(128) AZ\f6r{
DECLARE @OwnerName as NVARCHAR(128) J'wJe,
DECLARE curObject CURSOR FOR >@Na6BH5v
select 'Name' = name, |b!Bb<5
'Owner' = user_name(uid) >v1.Gm
from sysobjects M pz9}[`3g
where user_name(uid)=@OldOwner VAdUd {
order by name g/i.b&
OPEN curObject {3Dm/u%=9|
FETCH NEXT FROM curObject INTO @Name, @Owner _?Ly7*UML
WHILE(@@FETCH_STATUS=0) 2UBAk')O}
BEGIN T-js*
if @Owner=@OldOwner A#F6~QX(.9
begin u3jLe=Y'\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !G'wC0
exec sp_changeobjectowner @OwnerName, @NewOwner btDTC9O
end Izfq`zS+\s
-- select @name,@NewOwner,@OldOwner O? 7hT!{
FETCH NEXT FROM curObject INTO @Name, @Owner _~y-?(46K
END mF>{cVTF
close curObject |uJjO>8]|
deallocate curObject nbDjoZZ4
GO IY@N
10、SQL SERVER中直接循环写入数据 OskQ[
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declare @i int Kj-zEl
set @i=1 Lr "V
while @i<30 1b2xWzpG
begin Xw162/:h
insert into test (userid) values(@i) T9>,Mx%D[
set @i=@i+1 3Z}KRsp3
end i`w&{WTRQ
小记存储过程中经常用到的本周,本月,本年函数 4`?WdCW8
Dateadd(wk,datediff(wk,0,getdate()),-1) 'SWK{t \4
Dateadd(wk,datediff(wk,0,getdate()),6) +a+DiD>./
Dateadd(mm,datediff(mm,0,getdate()),0) v#5hK<9
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) LS<*5HWX
Dateadd(yy,datediff(yy,0,getdate()),0) GCxmqoQ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) }AS3]Lub@
上面的SQL代码只是一个时间段 Bv7os3xb
Dateadd(wk,datediff(wk,0,getdate()),-1) bhW&,"$Z
Dateadd(wk,datediff(wk,0,getdate()),6) )qD V3
就是表示本周时间段. 6ziBGU#.-
下面的SQL的条件部分,就是查询时间段在本周范围内的: fV!~SX6S
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ?]_A~_J!
而在存储过程中 - G=doP0
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) U@}P]'`'f
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) `mS0]/AV/