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。 kSiyMDY-
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一、基础 vE,^K6q0`
1、说明:创建数据库 Q>Klkd5(
CREATE DATABASE database-name qpFxl
2、说明:删除数据库 QxG^oxU}
drop database dbname ;Q,t65+Am
3、说明:备份sql server 0?oL zw&
--- 创建 备份数据的 device p*5_+u
USE master 1K#[Ef4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' OqS!y(
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--- 开始 备份 im9w|P 5
BACKUP DATABASE pubs TO testBack E oixw8hz
4、说明:创建新表 f.$[?Fi
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) d:|x e :
根据已有的表创建新表: pTGGJ,
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 R~iv%+
5、说明:删除新表 IagM#}m@
drop table tabname J*b Je"8
6、说明:增加一个列 '*L6@e#U
Alter table tabname add column col type M.,DXEZT
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。 q
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7、说明:添加主键: Alter table tabname add primary key(col) l!XCYg@67
说明:删除主键: Alter table tabname drop primary key(col) x#3*C|A
8、说明:创建索引:create [unique] index idxname on tabname(col....) u;
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删除索引:drop index idxname LDEc}XXb
注:索引是不可更改的,想更改必须删除重新建。 ~b*]jZwT
9、说明:创建视图:create view viewname as select statement /0qbRk i
删除视图:drop view viewname YFS6YA
10、说明:几个简单的基本的sql语句 riOaqV
选择:select * from table1 where 范围 MvZa;B
插入:insert into table1(field1,field2) values(value1,value2) L,.~VNy-
删除:delete from table1 where 范围 jZ-s6r2=
更新:update table1 set field1=value1 where 范围 q/zU'7%@
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! *]HnFP
排序:select * from table1 order by field1,field2 [desc] q=->) &D%
总数:select count as totalcount from table1 _p4]\LA
求和:select sum(field1) as sumvalue from table1 <A=1]'1\r
平均:select avg(field1) as avgvalue from table1 tqpO3
最大:select max(field1) as maxvalue from table1 @Q,Q"c2
最小:select min(field1) as minvalue from table1 O!nS3%De
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11、说明:几个高级查询运算词
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A: UNION 运算符 E \DA3lq
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。 :0B 7lDw
B: EXCEPT 运算符 )aGSZ1`/
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。 wHs1ge (
C: INTERSECT 运算符 ws9IO ?|&G
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。 X uE: dL?
注:使用运算词的几个查询结果行必须是一致的。 1|4,jm $
12、说明:使用外连接 XfE9QA[
A、left outer join: R+NiIoa
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。 Ws|`E`6O
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 P#!N
B:right outer join: gZ^Qt.6Z
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。 QPB,B>Z
C:full outer join: ;$&\:-6A#
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 2kDY+AN;
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二、提升 In_"iEo,
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) TyIjDG6tM
法一:select * into b from a where 1<>1 Rs5 lL-I
法二:select top 0 * into b from a \X&8EW
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Z[IM\# "
insert into b(a, b, c) select d,e,f from b; ?[Y(JO#
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Y&yfm/R u
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 f0SrPc v
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. bD ,X.
4、说明:子查询(表名1:a 表名2:b) Jf?6y~X>Y
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) O%kUj&h^
5、说明:显示文章、提交人和最后回复时间 }ww/e\|Nt=
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Bz_'>6w
6、说明:外连接查询(表名1:a 表名2:b) V($V8P/
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c KWY_eY_|
7、说明:在线视图查询(表名1:a ) "."(<c/3
select * from (SELECT a,b,c FROM a) T where t.a > 1; 0)Ephsw
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 !Nx1I
select * from table1 where time between time1 and time2 SC~k4&xy
select a,b,c, from table1 where a not between 数值1 and 数值2 HQ-++;Q
9、说明:in 的使用方法 ~>(~2083*;
select * from table1 where a [not] in ('值1','值2','值4','值6') )L:e0u
10、说明:两张关联表,删除主表中已经在副表中没有的信息 1X5g(B
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) <EUR:
11、说明:四表联查问题: u|t 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 ..... 8-x-?7
12、说明:日程安排提前五分钟提醒 1V1I[CxlX
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 z4SJxL
13、说明:一条sql 语句搞定数据库分页 *p
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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 /_l\7MeI
14、说明:前10条记录 ?p@J7{a
select top 10 * form table1 where 范围 `5@F'tKQ
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.) K{ar)_V/
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) .c-a$39
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 &$/
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(select a from tableA ) except (select a from tableB) except (select a from tableC) d)vP9vXy
17、说明:随机取出10条数据 oV:oc,
select top 10 * from tablename order by newid() D;C';O
18、说明:随机选择记录 XJe=+_K9
select newid() ffmtTJFC5
19、说明:删除重复记录 eo9/
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) #_35bg4h{
20、说明:列出数据库里所有的表名 >E<ib[vK[
select name from sysobjects where type='U' m@Yc&M~
21、说明:列出表里的所有的 &kIeW;X
select name from syscolumns where id=object_id('TableName') VGQ~~U7}@
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。 @Iz]:@\cJ
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 @M"gEeI9
显示结果: ).5X
type vender pcs x>[]Qk^?q
电脑 A 1 Io.RT+slB
电脑 A 1 D8Fi{?A#FV
光盘 B 2 d{4;qM#
光盘 A 2 GHGyeqNM
手机 B 3 iwJ_~
手机 C 3 2HFn\kjj.s
23、说明:初始化表table1 1'<C-[1
TRUNCATE TABLE table1
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24、说明:选择从10到15的记录 .}!.4J%q2
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 7_i8'(``
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三、技巧 ?+d`_/IB
1、1=1,1=2的使用,在SQL语句组合时用的较多 U0_^6zd_
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 06pvI}
如: _Ub
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if @strWhere !='' !e|\1v'0
begin !B3TLeh
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere R (~wSL*R>
end H\S)a FY[
else U7s$';y"%
begin O{X~,Em=q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' W r/-{Wt
end lv
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我们可以直接写成 _HUbE /
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere C[^V\?3ly:
2、收缩数据库 :k/Xt$`
--重建索引 ;>?h/tS6
DBCC REINDEX rR.It,,
DBCC INDEXDEFRAG @yuiNj.T
--收缩数据和日志 p:4jY|q
DBCC SHRINKDB h+[6i{
DBCC SHRINKFILE O_:l;D#i
3、压缩数据库 lxhb)]c
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dbcc shrinkdatabase(dbname) SB\%"nnV
4、转移数据库给新用户以已存在用户权限 OT{"C"%5t
exec sp_change_users_login 'update_one','newname','oldname' *1dDs^D#|
go ~ skp}g]
5、检查备份集 v=N?(6T
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' GDxv2^4
6、修复数据库 A8Ju+
ALTER DATABASE [dvbbs] SET SINGLE_USER glMHT,
GO ,L/ x\_28
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK |u&cN-}C d
GO P"w\hF
ALTER DATABASE [dvbbs] SET MULTI_USER |H5.2P&9-5
GO I/f\m}}ba
7、日志清除 V"4Z9Qg}
SET NOCOUNT ON E8#
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DECLARE @LogicalFileName sysname, ;Q;j@yx
@MaxMinutes INT, j!u)V1,
@NewSize INT 9-ozrw8t
USE tablename -- 要操作的数据库名 bU!
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 cl~Yx4
@MaxMinutes = 10, -- Limit on time allowed to wrap log. n"(!v7YNp
@NewSize = 1 -- 你想设定的日志文件的大小(M) P=94
-- Setup / initialize s\-,RQ1
DECLARE @OriginalSize int .9jKD*U|
SELECT @OriginalSize = size z]G|)16
FROM sysfiles (>v'0RA
WHERE name = @LogicalFileName \/NF??k,jk
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ukWn@q*
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + @?3f`l
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' LIZB!S@V \
FROM sysfiles 3 t,_{9
WHERE name = @LogicalFileName ix3LB!k<
CREATE TABLE DummyTrans Zl9@E;|=
(DummyColumn char (8000) not null) L)sgW(@2
DECLARE @Counter INT, [qYr~:` -[
@StartTime DATETIME, 5> x_G#W
@TruncLog VARCHAR(255) h|qJ{tUWc$
SELECT @StartTime = GETDATE(), vQMBJ&
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 8`q7Yss6F
DBCC SHRINKFILE (@LogicalFileName, @NewSize) TekUY m!G
EXEC (@TruncLog) |mb2<! ag{
-- Wrap the log if necessary. 7j]v_2S`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ~e{ @ 5.g
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1 R5pf
AND (@OriginalSize * 8 /1024) > @NewSize ZwmucY%3
BEGIN -- Outer loop. -#|D>
SELECT @Counter = 0 qA)OkR'm
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) kka5=u
BEGIN -- update ;5Sdx5`_
INSERT DummyTrans VALUES ('Fill Log') un{ZysmtB6
DELETE DummyTrans m@4Dz|
SELECT @Counter = @Counter + 1 Y2H-D{a27
END /at7H!
EXEC (@TruncLog) tb3VqFx
END y0 * rY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + d!,t_jM0
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + U.7fMc#
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' O `}EiyV
FROM sysfiles O*EV~{K
WHERE name = @LogicalFileName /A=w`[<
DROP TABLE DummyTrans 6%v9o?:~l
SET NOCOUNT OFF -=ZL(r
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8、说明:更改某个表 .G0 N+)
exec sp_changeobjectowner 'tablename','dbo' Luq4q95]
9、存储更改全部表 a{5SOe;;
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch y~SVD@
@OldOwner as NVARCHAR(128), J+6zV m
@NewOwner as NVARCHAR(128) @A/k"Ax{r
AS 1vj/6L
DECLARE @Name as NVARCHAR(128) F!omkN
DECLARE @Owner as NVARCHAR(128) `9~
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DECLARE @OwnerName as NVARCHAR(128) ,WT>"9+
DECLARE curObject CURSOR FOR 3N7H7(IR
select 'Name' = name, )g0fN+Mb
'Owner' = user_name(uid) {0zn~+
from sysobjects M;(,0d k
where user_name(uid)=@OldOwner UiFH*HT
order by name V`V\/s gj
OPEN curObject )pnyVTKt
FETCH NEXT FROM curObject INTO @Name, @Owner +&EXTZ@o
WHILE(@@FETCH_STATUS=0) FfoOJzf~o
BEGIN zsFzg.$3&
if @Owner=@OldOwner ;XKe$fsa~?
begin *ukyQZ9
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6
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exec sp_changeobjectowner @OwnerName, @NewOwner #+I'V\[
end kxn&f(5
-- select @name,@NewOwner,@OldOwner }Mcb\+[
FETCH NEXT FROM curObject INTO @Name, @Owner UtZ,q!sg
END j)A#}4jd
close curObject {1W:@6tl
deallocate curObject ccD+AGM.
GO g)D_!iz
10、SQL SERVER中直接循环写入数据 Fnw:alWr
declare @i int Ha'[uEDb
set @i=1 yIMqQSt79z
while @i<30 P]_d;\
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begin 2eT?qCxqc
insert into test (userid) values(@i) K1B9t{T
set @i=@i+1 MmuT~d/
end ^J!q>KJs
小记存储过程中经常用到的本周,本月,本年函数 bx@l6bpQ
Dateadd(wk,datediff(wk,0,getdate()),-1) V~J5x >O
Dateadd(wk,datediff(wk,0,getdate()),6) qQ&uU7,#
Dateadd(mm,datediff(mm,0,getdate()),0) -yYdj1y;
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0))
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Dateadd(yy,datediff(yy,0,getdate()),0) wp[Ug2;G
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) v3tJtb^'!
上面的SQL代码只是一个时间段 f:T?oR>2
Dateadd(wk,datediff(wk,0,getdate()),-1) % RSZ.
Dateadd(wk,datediff(wk,0,getdate()),6) KyvZ?R
就是表示本周时间段. Tb/TP3N
下面的SQL的条件部分,就是查询时间段在本周范围内的: TkbaoD
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) I[\~pi,
而在存储过程中 NFK`,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) eI
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) APQq F/