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。
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一、基础 ;Hmp f0$
1、说明:创建数据库 L\%orLEmK
CREATE DATABASE database-name t)f-mQz)
2、说明:删除数据库 7fHc[,
drop database dbname c!#:E`
3、说明:备份sql server :|+Qe e
--- 创建 备份数据的 device oD9^ID+
USE master E&`Nh5 JfC
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 1oiRW Re
--- 开始 备份 aNxAZMg
BACKUP DATABASE pubs TO testBack eJ0?=u!x
4、说明:创建新表 &V7M}@
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) k(t}^50^j
根据已有的表创建新表: iK5_u2]Q
A:create table tab_new like tab_old (使用旧表创建新表) 9QQyl\
B:create table tab_new as select col1,col2... from tab_old definition only ?t](a:IX
5、说明:删除新表 g[H',)A)
drop table tabname nKoiG*PI
6、说明:增加一个列 |~!U4D\
Alter table tabname add column col type t] aea*B
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。 -=`#fDvBn
7、说明:添加主键: Alter table tabname add primary key(col) 0@I S
说明:删除主键: Alter table tabname drop primary key(col) F@ Swe
8、说明:创建索引:create [unique] index idxname on tabname(col....) (wRgus
删除索引:drop index idxname S35~Cp
注:索引是不可更改的,想更改必须删除重新建。 .8(OT./
9、说明:创建视图:create view viewname as select statement {vEOn-(7
删除视图:drop view viewname m_+sR!\H8
10、说明:几个简单的基本的sql语句 UCWV2Mu
选择:select * from table1 where 范围 ag-f{UsTy
插入:insert into table1(field1,field2) values(value1,value2) H@bf'guA|B
删除:delete from table1 where 范围 nKa$1RMO
更新:update table1 set field1=value1 where 范围 2*w0t:Yxe
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1y#D?R=E
排序:select * from table1 order by field1,field2 [desc] 3cdTed-MIh
总数:select count as totalcount from table1 ~6YMD
求和:select sum(field1) as sumvalue from table1 '2^7-3_1
平均:select avg(field1) as avgvalue from table1 8N&+7FK
最大:select max(field1) as maxvalue from table1 1u3,'8F
最小:select min(field1) as minvalue from table1 Rk!X]-`=
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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 $odso;Hn
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 LUB${0BrA
B: EXCEPT 运算符 y!tC20Q
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。 (T`E!A0I\?
C: INTERSECT 运算符 yY?b.ty
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*cCb`h
注:使用运算词的几个查询结果行必须是一致的。 }>)[<;M>%
12、说明:使用外连接 (e(:P~Ry
A、left outer join: '5&s=M_
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。 [
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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 kuyjnSo9i
B:right outer join: jCbV,0)^
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。 _SW3_8SuM.
C:full outer join: ;r c`OZyE
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&{DOI%w
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二、提升 Tg!m`9s+
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~e6Brq
法一:select * into b from a where 1<>1 1UPC e
法二:select top 0 * into b from a '>r7V
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) EoK~S\dS
insert into b(a, b, c) select d,e,f from b; 94B\5I}
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) hzk cP
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 UQ{L{H
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Z&;uh_EC
4、说明:子查询(表名1:a 表名2:b) vZ.x{"n'~
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) [Xb@Wh:yG
5、说明:显示文章、提交人和最后回复时间 9eH$XYy
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b u ~A6bK*
6、说明:外连接查询(表名1:a 表名2:b) ,l<6GB2\
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 'Lu__NfN
7、说明:在线视图查询(表名1:a ) '7XIhN9
select * from (SELECT a,b,c FROM a) T where t.a > 1; H$y-8-&)
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 0`^&9nR
select * from table1 where time between time1 and time2 |JQQU!x
select a,b,c, from table1 where a not between 数值1 and 数值2 293M\5:
9、说明:in 的使用方法 o!)3?
select * from table1 where a [not] in ('值1','值2','值4','值6') #O+),,WS
10、说明:两张关联表,删除主表中已经在副表中没有的信息 :j+ ZI3@
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) @`gk|W3
11、说明:四表联查问题: h5(4*$%
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 ..... iof-7{+3_
12、说明:日程安排提前五分钟提醒 q
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 N;\'N
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13、说明:一条sql 语句搞定数据库分页 AvfNwE
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 y&V@^"`
14、说明:前10条记录 zAiXo__x
select top 10 * form table1 where 范围 rx] @A
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.) ax (c#
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ?#fu.YE\
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 E{|W(z,
(select a from tableA ) except (select a from tableB) except (select a from tableC) R6]Gk)5
17、说明:随机取出10条数据 6_FE 4RR[
select top 10 * from tablename order by newid() EM[WK+9>I{
18、说明:随机选择记录 DQr Y*nH
select newid() RJd(~1
19、说明:删除重复记录 3.*8)NW
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ))"6ern
20、说明:列出数据库里所有的表名 [n:<8ho
select name from sysobjects where type='U' }hhGu\
21、说明:列出表里的所有的 !O<)\)|g
select name from syscolumns where id=object_id('TableName') "g1)f"pL
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。 k7T`bYv
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 neLAEHV
显示结果: y !_C/!d
type vender pcs ]"?)Z
电脑 A 1 @0/+_2MH-
电脑 A 1 PK `D8)=u
光盘 B 2 t+!$[K0/
光盘 A 2 hpD!2 K3>
手机 B 3 ^zQ/mo,Z
手机 C 3 `Tv[DIVW
23、说明:初始化表table1 "$YJX1u3
TRUNCATE TABLE table1 |>dI/_'
24、说明:选择从10到15的记录 =w{Z@S(ukz
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc UWd=!h^dt
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三、技巧 7t0er'VC
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, 1pgU}sRk
如: QC}CRkp
if @strWhere !='' 'Wmx)0)
begin \RC'XKQ*n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere y.< m#Zzt
end %`1q-,>v
else {+Rog/;S'
begin 8~@c)Z;
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 62ws/8d6f
end Yp^rR }N
我们可以直接写成 +[\FD; >
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere a6) BqlJ
2、收缩数据库 ]1#e#M]#
--重建索引 Yfzl%wc
DBCC REINDEX %z,mB$LY
DBCC INDEXDEFRAG x"~8*V'0
--收缩数据和日志 ~d|A!S`
DBCC SHRINKDB m8d!<
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DBCC SHRINKFILE JR@`2YP-
3、压缩数据库 hG12ZZ D
dbcc shrinkdatabase(dbname) EVsC >rz
4、转移数据库给新用户以已存在用户权限 PgF*
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exec sp_change_users_login 'update_one','newname','oldname' 0dE@c./R i
go VJ]JjB
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5、检查备份集 CVL3VT1j0
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' T[UN@^DP(
6、修复数据库 -"'j7t:
ALTER DATABASE [dvbbs] SET SINGLE_USER F%@aB<Nu
GO Bg x'9p/
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK \Je0CD=e`
GO 3q\,$*D.
ALTER DATABASE [dvbbs] SET MULTI_USER KBx6NU?;PO
GO .6+Z^,3
7、日志清除 =5~jx
SET NOCOUNT ON FQ<Ju.
DECLARE @LogicalFileName sysname, :VRNs
@MaxMinutes INT, 4.[^\N
@NewSize INT ,St#Vla
USE tablename -- 要操作的数据库名 qNB<T('
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 mwHB(7YS,
@MaxMinutes = 10, -- Limit on time allowed to wrap log. $P^q!H4D
@NewSize = 1 -- 你想设定的日志文件的大小(M) S2sQOM@
-- Setup / initialize N4F.Y"R$(
DECLARE @OriginalSize int 6xTuNE1
SELECT @OriginalSize = size &^}1O:8e
FROM sysfiles Jh,]r?Bd
WHERE name = @LogicalFileName r1 !@hT
SELECT 'Original Size of ' + db_name() + ' LOG is ' + )rxX+k+b/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + f
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' G\2CR*
FROM sysfiles /Kql>$I
WHERE name = @LogicalFileName gY/"cq
CREATE TABLE DummyTrans {Aw#?#GPW
(DummyColumn char (8000) not null) iT3BF"ZqBO
DECLARE @Counter INT, fI ?>+I5
@StartTime DATETIME, C~,a!qY
@TruncLog VARCHAR(255) ! >(7+B3E*
SELECT @StartTime = GETDATE(), GfoLae
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' riY~%9iV'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {FeDvhv
EXEC (@TruncLog) t5\-v_mG=&
-- Wrap the log if necessary. #rMlI3;
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired .o(fe\KHf
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) =_JjmTy;a
AND (@OriginalSize * 8 /1024) > @NewSize mqD}BOif
BEGIN -- Outer loop. 2=,lcWr
SELECT @Counter = 0 } gyj0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) z+0I#kM"1
BEGIN -- update md)c0Bg8~
INSERT DummyTrans VALUES ('Fill Log') LG{,c.Qj*
DELETE DummyTrans %9KldcQ}~
SELECT @Counter = @Counter + 1 N7b8m?!
END Xv ]W(f1
EXEC (@TruncLog) 3%#3iZ=_
END nv*FT
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 5sj4;w[
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 7zXvnxYE
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' kbX8$xTM
FROM sysfiles 4Tb
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WHERE name = @LogicalFileName HSjlD{R
DROP TABLE DummyTrans 3`t#UY).F
SET NOCOUNT OFF V,lOt4b
8、说明:更改某个表 eenH0Ovv
exec sp_changeobjectowner 'tablename','dbo' 7Wf/$vRab
9、存储更改全部表 ,1~"eGl!
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch XKj|f`
@OldOwner as NVARCHAR(128), 3oF45`3FV
@NewOwner as NVARCHAR(128) BTqS'NuT
AS ! `
DECLARE @Name as NVARCHAR(128)
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DECLARE @Owner as NVARCHAR(128) TaZmRL
DECLARE @OwnerName as NVARCHAR(128) !"?#6-,Xn
DECLARE curObject CURSOR FOR ugdQAg
select 'Name' = name, ;#g"(
'Owner' = user_name(uid) `06;
from sysobjects pnl{&<$C%C
where user_name(uid)=@OldOwner {j.bC@hWw
order by name }"nItcp.1
OPEN curObject mitHT :%r2
FETCH NEXT FROM curObject INTO @Name, @Owner $Xv* ,Bq
WHILE(@@FETCH_STATUS=0) b z`+ k,*
BEGIN \pa"%c)
if @Owner=@OldOwner L*Tj^q!t+
begin =Gpylj7?~
set @OwnerName = @OldOwner + '.' + rtrim(@Name) .0zY}`
exec sp_changeobjectowner @OwnerName, @NewOwner ?&8^&brwG
end kvL=>
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-- select @name,@NewOwner,@OldOwner [<lHCQXJ/
FETCH NEXT FROM curObject INTO @Name, @Owner so,t
END 9'fQHwsJ
close curObject j8v8uZ;x
deallocate curObject 7x"R3
GO \r/rBa\
10、SQL SERVER中直接循环写入数据 LA!?H]
declare @i int &PR5q7
set @i=1 ^h(ew1:
while @i<30 K^
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begin F%@A6'c
insert into test (userid) values(@i) C8J[Up
set @i=@i+1 iw3FA4{(
end ef8s<5"4
小记存储过程中经常用到的本周,本月,本年函数 {BP{C=p
Dateadd(wk,datediff(wk,0,getdate()),-1) ax"+0L{
Dateadd(wk,datediff(wk,0,getdate()),6) w#ZoZZ wh
Dateadd(mm,datediff(mm,0,getdate()),0) ;"a=gr
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) :tz#v`3o
Dateadd(yy,datediff(yy,0,getdate()),0) 7o7)0l9!
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) p2hB8zL
上面的SQL代码只是一个时间段 )1]ZtU
Dateadd(wk,datediff(wk,0,getdate()),-1) vk}n,ecl
Dateadd(wk,datediff(wk,0,getdate()),6) e),q0%5
就是表示本周时间段. dcDyK!zz"
下面的SQL的条件部分,就是查询时间段在本周范围内的: !8TlD-ZT/
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) MUaq7B_>
而在存储过程中 prWk2_D;*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) K?6jXJseb
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qrb[-|ie&