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。 5^K\<+{~B
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一、基础 f]_'icP
1、说明:创建数据库 0xY</S
CREATE DATABASE database-name p zZ+!d
2、说明:删除数据库 =*R6O,
drop database dbname _+.JTk
3、说明:备份sql server q~^!Ck+#*
--- 创建 备份数据的 device [{`2FR:Cd
USE master Q'Tg0,,S
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' '50}QY_R.
--- 开始 备份 ,q;?zcC7
BACKUP DATABASE pubs TO testBack u 7:Iv
4、说明:创建新表 A"z9t#dv@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 74 &q2g{
根据已有的表创建新表: `FEa(Q+s
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only %lD+57=
5、说明:删除新表 txvo7?Y*4
drop table tabname O4Q"2
6、说明:增加一个列 `?O0)
Alter table tabname add column col type 7MGvw-Tpb7
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。 &isKU8n
7、说明:添加主键: Alter table tabname add primary key(col) dyk(/#*7W
说明:删除主键: Alter table tabname drop primary key(col) )N*Jc @Y@
8、说明:创建索引:create [unique] index idxname on tabname(col....) Mo5b
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删除索引:drop index idxname }m'n1tm;
注:索引是不可更改的,想更改必须删除重新建。 f!{@{\
9、说明:创建视图:create view viewname as select statement Ch\__t*v!
删除视图:drop view viewname ":f]egq
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10、说明:几个简单的基本的sql语句 uXk]
选择:select * from table1 where 范围 fY6~Z
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插入:insert into table1(field1,field2) values(value1,value2) 0?}n( f!S
删除:delete from table1 where 范围 &36SX<vZ
更新:update table1 set field1=value1 where 范围 KK6n"&TVa
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! wSw> UU
排序:select * from table1 order by field1,field2 [desc] 6']HmM
总数:select count as totalcount from table1 )XHn.>]nc
求和:select sum(field1) as sumvalue from table1 U
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平均:select avg(field1) as avgvalue from table1 XMiu}w!
最大:select max(field1) as maxvalue from table1 lB0`|UEb (
最小:select min(field1) as minvalue from table1 'uE;8.,
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11、说明:几个高级查询运算词 a HVzBcCPh
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A: UNION 运算符 PfZS"yk
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\"w/'XX
B: EXCEPT 运算符 D$7#&2y
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。 78Du
C: INTERSECT 运算符 6T4I,XrY_F
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。 bK.*v4RG
注:使用运算词的几个查询结果行必须是一致的。 WN<g _8QR
12、说明:使用外连接 s*s~yH6
A、left outer join: Q@7d:v
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。 Bp3E)l
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 zh|9\lf
B:right outer join: B]@25
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。 FJ-H
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C:full outer join: XbqMWQN*
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。 ]8}51y8
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二、提升
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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) Dnl<w<}ZU:
法一:select * into b from a where 1<>1 Pc_aEBq
法二:select top 0 * into b from a 76wNZv)9
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }f]Y^>-Ux
insert into b(a, b, c) select d,e,f from b; _'LZf=V0
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) -(t7>s
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 pF4Z4?W
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. =E5bM_P<K
4、说明:子查询(表名1:a 表名2:b) __2<v?\
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) ==& y9e
5、说明:显示文章、提交人和最后回复时间 2ozh!8aL
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b %IX)+
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6、说明:外连接查询(表名1:a 表名2:b) jx]P: ]
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c W*t]
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7、说明:在线视图查询(表名1:a ) BMy3tyO
select * from (SELECT a,b,c FROM a) T where t.a > 1; @phVfP"M
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 fEX=csZ86
select * from table1 where time between time1 and time2 mL=d EQ
select a,b,c, from table1 where a not between 数值1 and 数值2 ocFk#FW
9、说明:in 的使用方法 z
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select * from table1 where a [not] in ('值1','值2','值4','值6') Aeb(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 XzHR^^;u"*
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) b:D92pH
11、说明:四表联查问题: 8.[F3Tk=
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@o_bI
12、说明:日程安排提前五分钟提醒 B*,)@h
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 lI 4tW=
13、说明:一条sql 语句搞定数据库分页 2S{P(B
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 K5jt(7i
14、说明:前10条记录 PDuc;RG
select top 10 * form table1 where 范围 DK\XC%~m
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.) @Fb1D"!
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +yp:douERi
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 Z*ip=FYR
(select a from tableA ) except (select a from tableB) except (select a from tableC) d=PX}o^
17、说明:随机取出10条数据 N+=|WeZ
select top 10 * from tablename order by newid() 80Dn!9j*
18、说明:随机选择记录 RqtBz3v
select newid() eHy UY&N/
19、说明:删除重复记录 U}RBgPX!
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &ASR2J
20、说明:列出数据库里所有的表名 ujZ`T0
select name from sysobjects where type='U' bI55G#1G
21、说明:列出表里的所有的 h6Z:+
select name from syscolumns where id=object_id('TableName') @"-\e|[N
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。 \</!kY*3@t
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 kFv*>>X`
显示结果: Zd6ik&S
type vender pcs P[2!D)A
电脑 A 1 T&?g)
电脑 A 1 NOo?
光盘 B 2 (Jk&U8y
光盘 A 2 q(6.VU@
手机 B 3 n^Ca?|}
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手机 C 3 Y%.o
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23、说明:初始化表table1 nt#9j',6Rn
TRUNCATE TABLE table1 dRX~eIw
24、说明:选择从10到15的记录 }IyF|[
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc j#1G?MF
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三、技巧 3m1(l?fp
1、1=1,1=2的使用,在SQL语句组合时用的较多 q(?+01
"where 1=1" 是表示选择全部 "where 1=2"全部不选, rD].=.?1
如: m&:&z7^p
if @strWhere !='' USVDDqZ
begin 1f`De`zXzr
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere :A8}x=K
end H~a
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else fQJ`&9m*BF
begin H648 [H[k
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' s-$Wc)l
end
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我们可以直接写成 >R+-mP!nj
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere cb|+6m~
2、收缩数据库 ABN4kM>%
--重建索引 tk&AZb,sP
DBCC REINDEX ;xZ+1zmL0
DBCC INDEXDEFRAG _MBhwNBxZ
--收缩数据和日志 {p +&Q|
DBCC SHRINKDB )G/bP!^+(
DBCC SHRINKFILE xB
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3、压缩数据库 `tk oS
dbcc shrinkdatabase(dbname) gQy%T]
4、转移数据库给新用户以已存在用户权限 Ghgn<YG
exec sp_change_users_login 'update_one','newname','oldname' HwUaaK
go yQ$irS?
5、检查备份集 ppyy0E^M
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^M'(/O1
6、修复数据库 {821e&r
ALTER DATABASE [dvbbs] SET SINGLE_USER CS7b3p!I
GO u>*a@3$f
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 'J,UKK\5
GO 5/=$p:E>
ALTER DATABASE [dvbbs] SET MULTI_USER ';tlV
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GO n<.7tr0f\
7、日志清除 /)ZjI
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SET NOCOUNT ON FDMQLx f
DECLARE @LogicalFileName sysname, Z hfp>D
@MaxMinutes INT, Uwc%'=@
@NewSize INT Lce,]z\_
USE tablename -- 要操作的数据库名 g\q .
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 xMJ-=
@MaxMinutes = 10, -- Limit on time allowed to wrap log. FA+HR
@NewSize = 1 -- 你想设定的日志文件的大小(M) 6}^x#9\
-- Setup / initialize y2A\7&7
DECLARE @OriginalSize int @t%da^-HS"
SELECT @OriginalSize = size >C0B!MT?3%
FROM sysfiles _3`GZeGV
WHERE name = @LogicalFileName %;[DMc/
SELECT 'Original Size of ' + db_name() + ' LOG is ' + *k{Llq
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + b)diYsTH
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ^?cu9S3
FROM sysfiles yu;EL>G_AY
WHERE name = @LogicalFileName SZWNN#w60?
CREATE TABLE DummyTrans 2(eO5.FYF
(DummyColumn char (8000) not null) JtFq/&{i
DECLARE @Counter INT, Y&6jFT_
@StartTime DATETIME, {7:1F)Pj
@TruncLog VARCHAR(255) Y25`vE(
SELECT @StartTime = GETDATE(), D!`[fjs6A
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ef)RlzLOq
DBCC SHRINKFILE (@LogicalFileName, @NewSize) xV>
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EXEC (@TruncLog) ht-'O"d:
-- Wrap the log if necessary. REh"/d
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 5U2%X
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /TMVPnvz.
AND (@OriginalSize * 8 /1024) > @NewSize 'V&g"Pb
BEGIN -- Outer loop. q[U pP`Z%
SELECT @Counter = 0 vMzL+D2)
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) )G2Bx+Z;L
BEGIN -- update Ne
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INSERT DummyTrans VALUES ('Fill Log') -'&l!23a~
DELETE DummyTrans XJ7B?Zg
SELECT @Counter = @Counter + 1 7P$*qj~Vh
END ?NoNg^ Of
EXEC (@TruncLog) .x=abA$!9
END &lzY"Y*hA0
SELECT 'Final Size of ' + db_name() + ' LOG is ' + If&))$7u
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + D$FTnY
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' #wyceEa
FROM sysfiles zJX Z0yRT
WHERE name = @LogicalFileName Hk}P
DROP TABLE DummyTrans $.tT
SET NOCOUNT OFF MHpGG00,
8、说明:更改某个表 [vu;B4^"
exec sp_changeobjectowner 'tablename','dbo' {QEvc
9、存储更改全部表 +Z"Wa0wA
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch dpW`e>o
@OldOwner as NVARCHAR(128), upMs yLp(
@NewOwner as NVARCHAR(128) Y1Ql_
AS {MtJP:8Jp
DECLARE @Name as NVARCHAR(128) RPX.?;":
DECLARE @Owner as NVARCHAR(128) \#[DZOI~
DECLARE @OwnerName as NVARCHAR(128) g3ukx$Q{>
DECLARE curObject CURSOR FOR C^$E#|E9 N
select 'Name' = name, )v(rEY
'Owner' = user_name(uid) "-:H$
from sysobjects ,zjz "7'
where user_name(uid)=@OldOwner Y~Uf2(7b5
order by name /
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OPEN curObject \4 b^*`d
FETCH NEXT FROM curObject INTO @Name, @Owner 9"[,9HN
WHILE(@@FETCH_STATUS=0) PS~_a
BEGIN YMo8C(
if @Owner=@OldOwner E?]$Y[KJKs
begin gYt=_+-
set @OwnerName = @OldOwner + '.' + rtrim(@Name) V dJ
exec sp_changeobjectowner @OwnerName, @NewOwner Ktk?(49
end gPn0-)<
-- select @name,@NewOwner,@OldOwner +=W(c8~P
FETCH NEXT FROM curObject INTO @Name, @Owner BiU>h.4=\(
END _#~D{91
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close curObject 3uw3[
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deallocate curObject N!7?D'y
GO l(1.Ll
10、SQL SERVER中直接循环写入数据 ` 0@m,
declare @i int 3X Y"s"
set @i=1 UK6x]tE
while @i<30 _E9[4%f
begin ;-JF1p 7;
insert into test (userid) values(@i) b0}dy\dnQ
set @i=@i+1 d\-*Fmp(S
end bM'F8Fi
小记存储过程中经常用到的本周,本月,本年函数 +184|nJ<2
Dateadd(wk,datediff(wk,0,getdate()),-1) /Igz[P^\9
Dateadd(wk,datediff(wk,0,getdate()),6) h8WM4
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Dateadd(mm,datediff(mm,0,getdate()),0) X!V#:2JY
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) GYtgw9 "Y
Dateadd(yy,datediff(yy,0,getdate()),0) SEnr"}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) E|-oUzt
上面的SQL代码只是一个时间段 /{j._4c
Dateadd(wk,datediff(wk,0,getdate()),-1) }se3y
Dateadd(wk,datediff(wk,0,getdate()),6) wKJ|;o4;L
就是表示本周时间段. #+<YFm\i
下面的SQL的条件部分,就是查询时间段在本周范围内的: ,]t_9B QK
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) -V2f.QE%
而在存储过程中 `j3 OFC{7E
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) d v4~CW%Td
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) fNda&