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。 pYN.tD FO
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一、基础 ~#MXhhqB
1、说明:创建数据库 b
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CREATE DATABASE database-name ^iA_<@[`X[
2、说明:删除数据库 LO;7NK
drop database dbname m+|yk.md
3、说明:备份sql server k%D|17I
--- 创建 备份数据的 device je;C}4
USE master Uc%kyTBm1
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' )WNw0cV}J>
--- 开始 备份 M"\Iw'5$
BACKUP DATABASE pubs TO testBack {"PIS&]tR
4、说明:创建新表 %fuV]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 3QI. |;X
根据已有的表创建新表: F:7d}Jx
A:create table tab_new like tab_old (使用旧表创建新表) 43.Q);4
B:create table tab_new as select col1,col2... from tab_old definition only ^V}c8 P|
5、说明:删除新表 ]A=yj@o$xN
drop table tabname Y;)l
6、说明:增加一个列 P+L#p(K
Alter table tabname add column col type ;~,)6UX7
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。 N?EeT}m _
7、说明:添加主键: Alter table tabname add primary key(col) utu
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说明:删除主键: Alter table tabname drop primary key(col) FW"n+7T
8、说明:创建索引:create [unique] index idxname on tabname(col....) Nn#;Kjul.
删除索引:drop index idxname G)IK5zCDd
注:索引是不可更改的,想更改必须删除重新建。 V1#:[o63+
9、说明:创建视图:create view viewname as select statement CL3 b+r
删除视图:drop view viewname $;pHv<
10、说明:几个简单的基本的sql语句 z[Ah9tM%
选择:select * from table1 where 范围 1K#%mV_
插入:insert into table1(field1,field2) values(value1,value2) =f?vpKq40
删除:delete from table1 where 范围 b|-}?@&7&q
更新:update table1 set field1=value1 where 范围 i&TWIl8
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! cY^'Cj
排序:select * from table1 order by field1,field2 [desc] #=V\WQb
总数:select count as totalcount from table1 :u]QEZ@@
求和:select sum(field1) as sumvalue from table1 gb{8SG5ac
平均:select avg(field1) as avgvalue from table1 :\Q#W4~p
最大:select max(field1) as maxvalue from table1 T@jv0/(+
最小:select min(field1) as minvalue from table1 6bDizS}
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11、说明:几个高级查询运算词 |b4f3n
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A: UNION 运算符 hnimd~E52k
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。 g4 3(N!@g
B: EXCEPT 运算符 &gF9VY
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。 ~ <36vsk
C: INTERSECT 运算符 I@oSRB
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。 WF_v>g:g
注:使用运算词的几个查询结果行必须是一致的。 ZaYUf
12、说明:使用外连接 704_ehrlE
A、left outer join: :b0|v`FU
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。 .?`8B9w
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 m[CyvcF*u
B:right outer join: NTo[di\_
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。 <A(Bq'eQM
C:full outer join: !k Heslvi
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。 pAws{3(Q
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二、提升 _+j#.o>
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) E!RlH3})
法一:select * into b from a where 1<>1 99tUw'w
法二:select top 0 * into b from a 4,08`5{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) =9h!K:,k
insert into b(a, b, c) select d,e,f from b; 6 w'))Z
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) klAvi%^jE
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 '|<r[K
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. .}5qi;CA
4、说明:子查询(表名1:a 表名2:b) ~h:(9q8NLC
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) v@4vitbG9
5、说明:显示文章、提交人和最后回复时间 :='I>Gn
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b yl&s!I
6、说明:外连接查询(表名1:a 表名2:b) JEs@ky?{z
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c o%!s/Z1
7、说明:在线视图查询(表名1:a ) l"1*0jgBw
select * from (SELECT a,b,c FROM a) T where t.a > 1; D\Y,2!I
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 n[B[hAT
select * from table1 where time between time1 and time2 gFd*\Dk
select a,b,c, from table1 where a not between 数值1 and 数值2 |c>.xt~
9、说明:in 的使用方法 c^r WS&)P
select * from table1 where a [not] in ('值1','值2','值4','值6') Zoy)2E{
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ,^7]F"5
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) VsJKxa4
11、说明:四表联查问题: ==UYjbuU
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 ..... p~NHf\
12、说明:日程安排提前五分钟提醒 ][KlEE>W2
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 (_]!}N
13、说明:一条sql 语句搞定数据库分页 ;b(ww{&
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 {1_<\~J
14、说明:前10条记录 Xr:s-L
select top 10 * form table1 where 范围 :dQRrmM
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.) P4zwTEk`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ^f57qc3nF
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 [mQdc?n\
(select a from tableA ) except (select a from tableB) except (select a from tableC) Y/5(BK)
17、说明:随机取出10条数据 vN:!{)~z
select top 10 * from tablename order by newid() 4JyA+OD4 {
18、说明:随机选择记录
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select newid() FUf.3@}
19、说明:删除重复记录 9)8Cf%<(
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &6vWz6 !P
20、说明:列出数据库里所有的表名 +$Y*1{hyOo
select name from sysobjects where type='U' h$}PQ
21、说明:列出表里的所有的 1]9w9!j
select name from syscolumns where id=object_id('TableName') dVk(R9 8
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 QJ(5o7Tfn
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type f5p/cUzX
显示结果: w5^k84vye
type vender pcs <5^m`F5
电脑 A 1 PD^G$LT
电脑 A 1 Y9gw
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光盘 B 2 I:HrBhI)wP
光盘 A 2 4AKr.a0q
手机 B 3 =j{tFxJ
手机 C 3 4l{$dtKbI
23、说明:初始化表table1 )&O6d .
TRUNCATE TABLE table1 Mna
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24、说明:选择从10到15的记录 c%WO#}r|
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc xXc>YTK'
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三、技巧 m)LI|
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1、1=1,1=2的使用,在SQL语句组合时用的较多 AloL+eN@
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ^_i)XdPU
如: b;{"@b,Y
if @strWhere !='' Zk/ejhy0
begin `N&*+!O%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ^{{a
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end
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else Bz <I7h
begin )0/*j]Kf
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' mE5{)<N:C
end AorY#oq
我们可以直接写成 L N
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere j "'a5;Sy
2、收缩数据库 a5R.
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--重建索引 MPDRMGR@i
DBCC REINDEX i39ZBs@
DBCC INDEXDEFRAG uI9*D)
--收缩数据和日志 QeC\(4?
DBCC SHRINKDB IC5QH<.$C
DBCC SHRINKFILE x.Egl4b3
3、压缩数据库 sQj]#/yK:
dbcc shrinkdatabase(dbname) y/ Bo4fM
4、转移数据库给新用户以已存在用户权限 <ch}]-_
exec sp_change_users_login 'update_one','newname','oldname' N$=9R
go 39hep8+
5、检查备份集 ^N[ Cip}8
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' LT
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6、修复数据库 hRRxOr#*$
ALTER DATABASE [dvbbs] SET SINGLE_USER H la?\
GO ]{q=9DczG(
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK K#N9N@W jR
GO J4"A6`O
ALTER DATABASE [dvbbs] SET MULTI_USER ap'La|9t>
GO rAAx]nQ@
7、日志清除 >Oj$Dn=
SET NOCOUNT ON ;l~a|KW0
DECLARE @LogicalFileName sysname, l^}u S|c(
@MaxMinutes INT, x s\<!
@NewSize INT 6)ibXbH
USE tablename -- 要操作的数据库名 6u #eLs
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 1U#W=Fg'
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d,N6~?B
@NewSize = 1 -- 你想设定的日志文件的大小(M) -(F}=o'
-- Setup / initialize B1J,4
DECLARE @OriginalSize int xEurkR
SELECT @OriginalSize = size u6F>o+Td)
FROM sysfiles as]M%|/-I
WHERE name = @LogicalFileName P8}IDQ9
SELECT 'Original Size of ' + db_name() + ' LOG is ' + BO4;S/ O
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ;Z"MO@9:
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' f|M^UHt8*
FROM sysfiles <W!n lh
WHERE name = @LogicalFileName 2I}+AW!!=
CREATE TABLE DummyTrans ,*U-o}{8C?
(DummyColumn char (8000) not null) Za1mI^ L1
DECLARE @Counter INT, [ i,[^
@StartTime DATETIME, z/`+jIB
@TruncLog VARCHAR(255) l^ay*H
SELECT @StartTime = GETDATE(), ?8{Os;!je
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' x'|9A?ez@Z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) .`m|Uf#"
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EXEC (@TruncLog) $x`HmL3Sb
-- Wrap the log if necessary. !L{mE&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 3e;|KU
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /KWdIP#
AND (@OriginalSize * 8 /1024) > @NewSize
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BEGIN -- Outer loop. ?wPTe^Qtv
SELECT @Counter = 0 #7Q9^rG
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) D.:`]W|
BEGIN -- update vT0Op e6m
INSERT DummyTrans VALUES ('Fill Log') } =)u_q
DELETE DummyTrans TK18U*z7J
SELECT @Counter = @Counter + 1 'g,_ lF
END x%r$/=
EXEC (@TruncLog) (kB
END -k7b#
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + i_Q1\_m !
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ycm .qud
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ~EY)c~H
FROM sysfiles 3'kKbrk [
WHERE name = @LogicalFileName K"XwSZ/
DROP TABLE DummyTrans T@.+bD
SET NOCOUNT OFF G gA:;f46
8、说明:更改某个表 X!LiekU!D
exec sp_changeobjectowner 'tablename','dbo' 9ybR+dGm+
9、存储更改全部表 Z(c
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ;Us6:}s
@OldOwner as NVARCHAR(128), SQ> Yf\
@NewOwner as NVARCHAR(128) Bo8f52|
AS Z(tJd,
DECLARE @Name as NVARCHAR(128) 0.wF2!V.
DECLARE @Owner as NVARCHAR(128) D((/fT)eD
DECLARE @OwnerName as NVARCHAR(128) ?]Hs~n-
DECLARE curObject CURSOR FOR VnSO>O
select 'Name' = name, 7F>]zrbK
'Owner' = user_name(uid) kVM*[<k
from sysobjects ~&p]kmwXSX
where user_name(uid)=@OldOwner q6$6:L,<
order by name d+v|&yN
OPEN curObject USN'-Ah
FETCH NEXT FROM curObject INTO @Name, @Owner o
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WHILE(@@FETCH_STATUS=0) ?>*d82yO
BEGIN
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if @Owner=@OldOwner i^jM9MAi
begin D*~Q;q>
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fJ.=,9:<
exec sp_changeobjectowner @OwnerName, @NewOwner qXq#A&
end nbP}a?XC
-- select @name,@NewOwner,@OldOwner :KvZP:T
FETCH NEXT FROM curObject INTO @Name, @Owner &$CyT6mb^
END ~s4JGV~R
close curObject 6x(b/`VW
deallocate curObject @q<h.#9
GO !gLJBp
10、SQL SERVER中直接循环写入数据 }0E@eL
declare @i int D[@-`F
set @i=1 U&B(uk(2
while @i<30 )E=B;.FH
begin hl**G4z9q
insert into test (userid) values(@i) GYIQ[#'d7
set @i=@i+1 A@lM=
end jWxa
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小记存储过程中经常用到的本周,本月,本年函数 7mi*#X}
Dateadd(wk,datediff(wk,0,getdate()),-1) ?^!J:D?
Dateadd(wk,datediff(wk,0,getdate()),6) g~K-'Nw
Dateadd(mm,datediff(mm,0,getdate()),0) bt=D<YZk
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 8M!9gvcaO
Dateadd(yy,datediff(yy,0,getdate()),0) b_{+O qI
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Th%w-19,8
上面的SQL代码只是一个时间段 lmoYQFkYP
Dateadd(wk,datediff(wk,0,getdate()),-1) |AvsT{2
Dateadd(wk,datediff(wk,0,getdate()),6) Om:Gun\%
就是表示本周时间段. t"%~r3{
下面的SQL的条件部分,就是查询时间段在本周范围内的: AM!P?${a
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) !lEV^SQJs
而在存储过程中 d:&cq8^
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) R6;229e
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) w\d1