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。 ]{I>HA5[
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一、基础
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1、说明:创建数据库 tA9Ew{3s
CREATE DATABASE database-name FRQkD%k
2、说明:删除数据库 .mOm@<Xdg
drop database dbname Oo
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3、说明:备份sql server CurU6x1
--- 创建 备份数据的 device MR,A{X
USE master YeB C6`7y
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' L$ jii
--- 开始 备份 `];ne]xM
BACKUP DATABASE pubs TO testBack Ad-_=a%
4、说明:创建新表 !L_xcov!Y
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [G[{?{
根据已有的表创建新表: BL%&n*&
A:create table tab_new like tab_old (使用旧表创建新表) 715J1~aRNr
B:create table tab_new as select col1,col2... from tab_old definition only |@?='E?h
5、说明:删除新表 kpk ^Uw%f
drop table tabname DYew6B-
6、说明:增加一个列 dLf
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Alter table tabname add column col type ?pA_/wwp
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。 e`5:46k|
7、说明:添加主键: Alter table tabname add primary key(col) =Hj3o_g-
说明:删除主键: Alter table tabname drop primary key(col) -ilhC Y@M
8、说明:创建索引:create [unique] index idxname on tabname(col....) vJW`aN1<I3
删除索引:drop index idxname 7mb5z/N
注:索引是不可更改的,想更改必须删除重新建。 m
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9、说明:创建视图:create view viewname as select statement P)ne^_
删除视图:drop view viewname -'i[/{
10、说明:几个简单的基本的sql语句 6S(`Bw8h
选择:select * from table1 where 范围 5Iv"
插入:insert into table1(field1,field2) values(value1,value2) ]0{,P
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删除:delete from table1 where 范围 GW9,%}l^;
更新:update table1 set field1=value1 where 范围 'n?"f |G
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! w}29#F\]R
排序:select * from table1 order by field1,field2 [desc] \`8F.oZ^)
总数:select count as totalcount from table1 kC'm |Y@T
求和:select sum(field1) as sumvalue from table1 %,d+jBM
平均:select avg(field1) as avgvalue from table1 U:$`M,762Z
最大:select max(field1) as maxvalue from table1 ubsx NCqD
最小:select min(field1) as minvalue from table1 D9n+eZ
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11、说明:几个高级查询运算词 _ CzAv%
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A: UNION 运算符 0BOL0<Wq
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 tV7{j'If
B: EXCEPT 运算符 cr^R9dv
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 "7?x aGh8
C: INTERSECT 运算符 1+tPd7U
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 5)w;0{X!P
注:使用运算词的几个查询结果行必须是一致的。 @*$"6!3s5
12、说明:使用外连接 7 S%`]M4;
A、left outer join: %<h2^H\O
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。 V.o*`V
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 J!'IkC$>
B:right outer join: >Q)S-4iR
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 g
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C:full outer join: 4&~*;an7
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 I*(7(>zgyv
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二、提升 \<b42\a}
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 73!])!SVI
法一:select * into b from a where 1<>1 <*p
法二:select top 0 * into b from a H#bu3*'
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) F+V[`w*k
insert into b(a, b, c) select d,e,f from b; "2I{T
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) #Vm)wH3
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 R7x*/?
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. "(:8$Fb
4、说明:子查询(表名1:a 表名2:b) f{'NO`G
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) JJP!9<
5、说明:显示文章、提交人和最后回复时间 y<y9'tx
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b _Aw-{HE'
6、说明:外连接查询(表名1:a 表名2:b) j9=)^?
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c v)'Uoe"R%
7、说明:在线视图查询(表名1:a ) ay28%[Q b4
select * from (SELECT a,b,c FROM a) T where t.a > 1; JOki4N
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 <Oj'0NK-
select * from table1 where time between time1 and time2 ?j}
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select a,b,c, from table1 where a not between 数值1 and 数值2 oMN
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9、说明:in 的使用方法 e#?rK=C?9
select * from table1 where a [not] in ('值1','值2','值4','值6') X-%91z:o58
10、说明:两张关联表,删除主表中已经在副表中没有的信息 o^BX:\}
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Vb~;"WABo
11、说明:四表联查问题: l+O\oD?-
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 ..... b28C(
12、说明:日程安排提前五分钟提醒 AE%zqvp>
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 NbUibxJ
13、说明:一条sql 语句搞定数据库分页 eZ(o _
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 {.UK{nA?sm
14、说明:前10条记录 ;S+"z;$m
select top 10 * form table1 where 范围 FFf
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) d,t'e?
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) S,C/l1s
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 +#g4Crb
(select a from tableA ) except (select a from tableB) except (select a from tableC) 8noo^QO
17、说明:随机取出10条数据 xllmF)]*Y
select top 10 * from tablename order by newid() 7L!q{%}
18、说明:随机选择记录 )/t=g
select newid() Uql7s:!,U
19、说明:删除重复记录 'ExQG$t
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) "ScY'<
20、说明:列出数据库里所有的表名 vn96o]n
select name from sysobjects where type='U' E~,Wpl}
21、说明:列出表里的所有的 ]@sLX ek
select name from syscolumns where id=object_id('TableName') x4@IK|CE
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。 `mKK1x
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 X!]p8Q y
显示结果: ybgw#jv=
type vender pcs ?w@KF%D
电脑 A 1 jiLt *>I
电脑 A 1 Oxh.&
光盘 B 2 97VS
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光盘 A 2 6x!
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手机 B 3 q.p.y0
手机 C 3 ,j\UZ
23、说明:初始化表table1 yrR,7vJ
TRUNCATE TABLE table1 +RD{<~i
24、说明:选择从10到15的记录 /909ED+)>9
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 74%Uojl"
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三、技巧 &$_#{?dPt
1、1=1,1=2的使用,在SQL语句组合时用的较多 P.]O8r
"where 1=1" 是表示选择全部 "where 1=2"全部不选, D-\z'gS
如: :FI4GR*?
if @strWhere !='' XFvPc
begin eX{Tyd{
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere @{8SC~ha
end 4> (OM|X=9
else 5> =Ia@I
begin ZDl(q~4?z
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' @jH8x!5u:
end |", /
我们可以直接写成 v
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Z_?r5M;
2、收缩数据库 LgoUD*MbQ
--重建索引 1V 2"sE
DBCC REINDEX nsV;6^>
DBCC INDEXDEFRAG }G[Qm2k
--收缩数据和日志 7_AcvsdW
DBCC SHRINKDB / 9soUt
DBCC SHRINKFILE _cXLQ)-
3、压缩数据库 w]VdIS
dbcc shrinkdatabase(dbname) z
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4、转移数据库给新用户以已存在用户权限 rfc;
exec sp_change_users_login 'update_one','newname','oldname' KN zm)O
go iY4FOt7\
5、检查备份集 NxQ+z^o\
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' pL)o@-k#%
6、修复数据库 qi-!iT(fe
ALTER DATABASE [dvbbs] SET SINGLE_USER h8tKYm
GO 5oE!^bF?
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK (8OaXif
GO EU-=\Y
ALTER DATABASE [dvbbs] SET MULTI_USER TZ%u;tBH:
GO CZ_ (IT7
7、日志清除 O[#pB.
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SET NOCOUNT ON MzO4Yv"A
DECLARE @LogicalFileName sysname, BF>3CW7
@MaxMinutes INT, 3 ~^ }R
@NewSize INT >gTrui{,
USE tablename -- 要操作的数据库名 mkOj&Q
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9DP6g<>B
@MaxMinutes = 10, -- Limit on time allowed to wrap log. uWKc
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@NewSize = 1 -- 你想设定的日志文件的大小(M) O U3KB
-- Setup / initialize m\xE8D(,
DECLARE @OriginalSize int <xQHb^:
SELECT @OriginalSize = size Jri"Toz0
FROM sysfiles )mMHwLDwH
WHERE name = @LogicalFileName _Tj`
SELECT 'Original Size of ' + db_name() + ' LOG is ' + `?R~iLIAq
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + .ahYjn
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ;.P9t`*
FROM sysfiles !FVXNl
WHERE name = @LogicalFileName +gQoYlso
CREATE TABLE DummyTrans 7'9~Kx&+
(DummyColumn char (8000) not null) Iz<}>J B
DECLARE @Counter INT, IT_Fs|$
@StartTime DATETIME, 5%n
@TruncLog VARCHAR(255)
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SELECT @StartTime = GETDATE(), i0-zGEMB.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' X}$uvB}+>
DBCC SHRINKFILE (@LogicalFileName, @NewSize) [#emm1k
EXEC (@TruncLog) _PeBV<
-- Wrap the log if necessary. NbtNu$%t
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired O7z-4r
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) U`fxe`nVa
AND (@OriginalSize * 8 /1024) > @NewSize 2_]"9d4
BEGIN -- Outer loop. XVKR}I
SELECT @Counter = 0 K)C9)J<
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) %l7|+%M.{
BEGIN -- update n/fMq,<8
INSERT DummyTrans VALUES ('Fill Log') 1]uHaI(
DELETE DummyTrans lC ^NhQi
SELECT @Counter = @Counter + 1 *?Sp9PixP
END jI(}CT`g
EXEC (@TruncLog) EJrn4QOs
END JtrLTo
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,U#$Qb 12
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + w1+xlM,,9
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' lJloa'%v9
FROM sysfiles iCYo?>
WHERE name = @LogicalFileName .?YLD+\A
DROP TABLE DummyTrans [9E<z2H
SET NOCOUNT OFF Wl:vO^
8、说明:更改某个表 ?Rj)x%fN
exec sp_changeobjectowner 'tablename','dbo' ie!ik
9、存储更改全部表 _ ecKX</Q
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch aa1^cw 5}
@OldOwner as NVARCHAR(128), 420cJ{;A
@NewOwner as NVARCHAR(128) dfBTx6/F
AS "3"9sIZ(
DECLARE @Name as NVARCHAR(128) U0/X!@F-
DECLARE @Owner as NVARCHAR(128) g6kVHxh-
DECLARE @OwnerName as NVARCHAR(128) 4EiEE{9V
DECLARE curObject CURSOR FOR N| dwuBW
select 'Name' = name, BEkxH.
'Owner' = user_name(uid) e!67Na0X(
from sysobjects 9
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where user_name(uid)=@OldOwner NyTv~8A`)
order by name 0b0.xz\~U
OPEN curObject &?=UP4[oif
FETCH NEXT FROM curObject INTO @Name, @Owner W^Jh'^E
WHILE(@@FETCH_STATUS=0) 5};Nv{km^2
BEGIN )kSE5|:pi
if @Owner=@OldOwner b=!G3wVw<
begin rQ^$)%uP
set @OwnerName = @OldOwner + '.' + rtrim(@Name) p}j$p'D.RI
exec sp_changeobjectowner @OwnerName, @NewOwner n)(E 0h
end XO*62>Ed
-- select @name,@NewOwner,@OldOwner JR1/\F<}
FETCH NEXT FROM curObject INTO @Name, @Owner 9:!<=rk
END P7;=rSW
close curObject (dxkDS-G
deallocate curObject _[8BAm
GO |7V:~MTkk&
10、SQL SERVER中直接循环写入数据 Xx~XW^lsh
declare @i int RSLMO8
set @i=1 Jp<Y2-
while @i<30 TM8WaH
begin t7#C&B
insert into test (userid) values(@i) 8lo /BGxS>
set @i=@i+1 {BBL`tg60
end &n.7~C]R
小记存储过程中经常用到的本周,本月,本年函数 [WDtr8L
Dateadd(wk,datediff(wk,0,getdate()),-1) AKVll
Dateadd(wk,datediff(wk,0,getdate()),6) Htseu`>_$
Dateadd(mm,datediff(mm,0,getdate()),0) 0i2ZgOJ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) R!i9N'gGG(
Dateadd(yy,datediff(yy,0,getdate()),0) s5X .(;+
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \7QAk4I~
上面的SQL代码只是一个时间段 R <+K&_
Dateadd(wk,datediff(wk,0,getdate()),-1) ]:B|_|H
Dateadd(wk,datediff(wk,0,getdate()),6) jOppru5U
就是表示本周时间段. wD-(3ZVd4
下面的SQL的条件部分,就是查询时间段在本周范围内的: aO9a G*9T
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) @3/.W +
而在存储过程中 6@TGa%:G
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) GVT+c@Gx
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) *%^Vq