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。 E?mp6R]}%
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一、基础 eW)I}z+{
1、说明:创建数据库 W~F/ZrT3A
CREATE DATABASE database-name c.Y8CD.tqL
2、说明:删除数据库 ;8T=uCi
drop database dbname ~BZV:Es
3、说明:备份sql server ;QQ7vo
--- 创建 备份数据的 device 5#)<rK
USE master HdUW(FZ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' d-sh6q5
--- 开始 备份 BznA)EK?@
BACKUP DATABASE pubs TO testBack ebe@.ZVSi
4、说明:创建新表 -l@W)?$
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) b=UMoWS
根据已有的表创建新表: 4.B*B3
A:create table tab_new like tab_old (使用旧表创建新表) j2 ^T:q[
B:create table tab_new as select col1,col2... from tab_old definition only l&Ghs@>Kl
5、说明:删除新表 dO;vcgvb
drop table tabname t)Q@sKT6
6、说明:增加一个列 ('-}"3
Alter table tabname add column col type ?1:/
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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。 SQU%N
7、说明:添加主键: Alter table tabname add primary key(col) ]~Vu-@
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说明:删除主键: Alter table tabname drop primary key(col) #ljg2:I+
8、说明:创建索引:create [unique] index idxname on tabname(col....) pf@}4PN}
删除索引:drop index idxname *.c9$`s
注:索引是不可更改的,想更改必须删除重新建。 (I
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9、说明:创建视图:create view viewname as select statement 50aWFJYw
删除视图:drop view viewname &jZ|@K?
10、说明:几个简单的基本的sql语句 &[Zap6]
选择:select * from table1 where 范围 #(+HSZm
插入:insert into table1(field1,field2) values(value1,value2) i;zGw.;Q
删除:delete from table1 where 范围 F` 5/9?;|
更新:update table1 set field1=value1 where 范围 !# :$u=
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! RhNaYO
排序:select * from table1 order by field1,field2 [desc] +4g%?5'
总数:select count as totalcount from table1 rY?F6'}
求和:select sum(field1) as sumvalue from table1 >MWpYp
平均:select avg(field1) as avgvalue from table1 ynbpew aa
最大:select max(field1) as maxvalue from table1 P&3/nL$9N
最小:select min(field1) as minvalue from table1 :@`(}5F4
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11、说明:几个高级查询运算词 :KP'xf.
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A: UNION 运算符 `6N-MsP
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Y+u-J4bj
B: EXCEPT 运算符 UxcDDa/j2T
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 {dA
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C: INTERSECT 运算符 B H0#Q5
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ho]!G498
注:使用运算词的几个查询结果行必须是一致的。 MupW=3.38
12、说明:使用外连接 C$td{tM
A、left outer join: #!Cter2
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。 #G+
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 -Bo~"q
B:right outer join: TflS@Z7C
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。 c`i=(D<
C:full outer join: oUvk2]H
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。 <%>n@A
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二、提升 |] !o*7"4
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) mOgOHb2
法一:select * into b from a where 1<>1
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法二:select top 0 * into b from a }\ 939Y
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ]]=-AuV.
insert into b(a, b, c) select d,e,f from b; g{W6a2
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) blfE9Oy
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 {pe7]P?
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. HCx%_9xlm
4、说明:子查询(表名1:a 表名2:b) B>|U-[A
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) ,M@m4bx
5、说明:显示文章、提交人和最后回复时间 'y6!%k*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b j[/SXF\=
6、说明:外连接查询(表名1:a 表名2:b) ]opW; |{e
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |J<pLz
7、说明:在线视图查询(表名1:a ) XiRT|%j
select * from (SELECT a,b,c FROM a) T where t.a > 1; C9mzg
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)=XEh8P
select * from table1 where time between time1 and time2 ]]uzl0LH
select a,b,c, from table1 where a not between 数值1 and 数值2 >C:"$x2"#(
9、说明:in 的使用方法 Z;fm;X%4
select * from table1 where a [not] in ('值1','值2','值4','值6') yC'hwoQ`
10、说明:两张关联表,删除主表中已经在副表中没有的信息 V%BJNJ
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5fegWCJ
11、说明:四表联查问题: -4vHK!l
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... (K*/Vp
12、说明:日程安排提前五分钟提醒 &e
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 UbY~xs7_
13、说明:一条sql 语句搞定数据库分页 f3zfRhkIk
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 c}IX"
14、说明:前10条记录 Tr+h$M1_Ja
select top 10 * form table1 where 范围 $m:2&lU3
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) &Mhv XHI
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) [+%d3+27
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 GX7 eRqz >
(select a from tableA ) except (select a from tableB) except (select a from tableC) 2q-:p8
17、说明:随机取出10条数据 bB;~,W&E1
select top 10 * from tablename order by newid() (ET ;LH3
18、说明:随机选择记录 @ .Z[M
select newid() +~w?Xw,
19、说明:删除重复记录 '9-axIj70
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) OS4]Y
20、说明:列出数据库里所有的表名 `;5VH ]V
select name from sysobjects where type='U' "%oH@
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21、说明:列出表里的所有的 <78$]Z2we
select name from syscolumns where id=object_id('TableName') <.r ]dCf
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。 qe5tcv}u
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 I&pr_~.
显示结果: !F+|Y"c
type vender pcs U|Bsa(?nx
电脑 A 1
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电脑 A 1 &G-#*OG
光盘 B 2 S2rEy2\}:
光盘 A 2 !2zo]v4?
手机 B 3 FJsK5-
手机 C 3 ?kL|>1TY
23、说明:初始化表table1 'v\1:zi
TRUNCATE TABLE table1 &/>;LgN
24、说明:选择从10到15的记录 0" U5oP[
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc xvwD3.1
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三、技巧 @-wNrW$
1、1=1,1=2的使用,在SQL语句组合时用的较多 [&h#iTRT
"where 1=1" 是表示选择全部 "where 1=2"全部不选, cBz!U8(
如: ZnvEv;P
if @strWhere !='' V!T^wh;
begin '}jf#C1$c
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere BIxV|\k
end '1W!xQ}E
else MV"E?}0
begin jo9J%vo
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 42rj6m\
end yz[%MXI
我们可以直接写成 +1otn~(E
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Nb~,`bu,2
2、收缩数据库 w^06z,
--重建索引 H$z>OS_6U
DBCC REINDEX BFBR/d[&
DBCC INDEXDEFRAG j 0g5<M
--收缩数据和日志 Nk96"P$P
DBCC SHRINKDB $|4cJ#;^L
DBCC SHRINKFILE !oZQ2z~
3、压缩数据库 |-~b$nUe
dbcc shrinkdatabase(dbname) 0LetsDN7I
4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' W|)GV0YM
go 99 <4t$KH
5、检查备份集 E%<w5d.lq
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' UZzNVIXA%
6、修复数据库 ]i-P-9PA4
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO P@qMJ}<j
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK jCU=+b=
GO z%OuI 8"'
ALTER DATABASE [dvbbs] SET MULTI_USER &MCy.(jN
GO }5Yj
7、日志清除 #v{ Y=$L
SET NOCOUNT ON T"n{WmVQ
DECLARE @LogicalFileName sysname, yC0C`oC
@MaxMinutes INT, JZ `>|<W
@NewSize INT r
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USE tablename -- 要操作的数据库名 ^'m\D;
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 *6:v}#b[
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ^#]c0
@NewSize = 1 -- 你想设定的日志文件的大小(M) xC<=~(
-- Setup / initialize qs=Gj?GwGQ
DECLARE @OriginalSize int *i@sUM?K
SELECT @OriginalSize = size +T9Q_e*
FROM sysfiles eymi2-a<
WHERE name = @LogicalFileName ? m&IF<b
SELECT 'Original Size of ' + db_name() + ' LOG is ' + :.Y|I[\E%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + he"L*p*H
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' O/mR9[}
FROM sysfiles r]v&t
WHERE name = @LogicalFileName &=YSM.G
CREATE TABLE DummyTrans Yl$X3wi
(DummyColumn char (8000) not null) ODm&&W#*
DECLARE @Counter INT, %B@!
@StartTime DATETIME, >^dyQyK
@TruncLog VARCHAR(255) $0_^=DEW
SELECT @StartTime = GETDATE(), &,J*_F<s2<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' M|d={o9Hp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) djWcbC=g_
EXEC (@TruncLog) hw;0t,1
-- Wrap the log if necessary. 'iJDWxCD
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired =/[ltUKs:a
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) JjQ8|En
AND (@OriginalSize * 8 /1024) > @NewSize T'E]
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BEGIN -- Outer loop. n|WfaJQZ
SELECT @Counter = 0 F9-[%l
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) uS~#4;R
BEGIN -- update 4CLsY n?
INSERT DummyTrans VALUES ('Fill Log') n=q=zn;
DELETE DummyTrans uKv&7p@|_)
SELECT @Counter = @Counter + 1 hi!`9k
END %dc3z"u
EXEC (@TruncLog) .;9jdGBf
END 2UiR~P]%
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ~/2g)IS
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + {;*}WPYb
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ]bm=LA
FROM sysfiles </= CZy5w
WHERE name = @LogicalFileName 5y]io
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DROP TABLE DummyTrans >-M ]:=L
SET NOCOUNT OFF #b'N}2'p#V
8、说明:更改某个表 ^5>s7SGB"
exec sp_changeobjectowner 'tablename','dbo' JBz}|MD
9、存储更改全部表 -IadHX}]t
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch BWh}^3?l
@OldOwner as NVARCHAR(128), :}Ok$^5s
@NewOwner as NVARCHAR(128) OOok hZd`
AS K1OkZ6kl
DECLARE @Name as NVARCHAR(128) r$ =qQ7^#
DECLARE @Owner as NVARCHAR(128) zN%97q_
DECLARE @OwnerName as NVARCHAR(128) @D~B{Hg
DECLARE curObject CURSOR FOR ,9d9_c.T
select 'Name' = name, /%!~x[BeJ>
'Owner' = user_name(uid) e'34Pw!m
from sysobjects Pe}PH
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where user_name(uid)=@OldOwner gw^'{b
order by name V>Fesm"aq
OPEN curObject %t*[T
FETCH NEXT FROM curObject INTO @Name, @Owner ~h!
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WHILE(@@FETCH_STATUS=0) GX
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BEGIN zzJja/mp
if @Owner=@OldOwner vg)Z]F=t(
begin >^=gDJ\a
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ~M5:=zKQ
exec sp_changeobjectowner @OwnerName, @NewOwner 7NJFWz!
end ?DPHo)w
-- select @name,@NewOwner,@OldOwner Z.'syGuV
FETCH NEXT FROM curObject INTO @Name, @Owner w~|1Wd<v
END u`_*g^5q"
close curObject pISp*&
deallocate curObject M(enRs3`O
GO L2fZ{bgy
10、SQL SERVER中直接循环写入数据 )T1iN(Z
declare @i int }^Gd4[(,g
set @i=1 :_xh(W+2<
while @i<30 3-C\2
begin Ja|{1&J.
insert into test (userid) values(@i) px=]bALU
set @i=@i+1 E)W@{?.o#
end CE ~@}`
小记存储过程中经常用到的本周,本月,本年函数 \K7t'20
Dateadd(wk,datediff(wk,0,getdate()),-1) F}36IM9/:
Dateadd(wk,datediff(wk,0,getdate()),6) o5!f#Y
Dateadd(mm,datediff(mm,0,getdate()),0) hi|!
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) c7K!cfO:{N
Dateadd(yy,datediff(yy,0,getdate()),0) 8md*wEjk
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) irKIy
上面的SQL代码只是一个时间段 bMm3F%FFq&
Dateadd(wk,datediff(wk,0,getdate()),-1) MzkkcQLK
Dateadd(wk,datediff(wk,0,getdate()),6) mrM4RoO
就是表示本周时间段. Qhn;`9+L
下面的SQL的条件部分,就是查询时间段在本周范围内的: fvqd'2 t
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) T2=HG Z
而在存储过程中 s_[VHPN
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) DMn4ll|
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $4m*kQ