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。 N5tFEV'G
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一、基础 JtF)jRB0,
1、说明:创建数据库 {
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CREATE DATABASE database-name i;:}{G<
2、说明:删除数据库 &7Xsn^opku
drop database dbname ${97G#
3、说明:备份sql server $-(lp0\*
--- 创建 备份数据的 device _6L'}X$)N
USE master 7}(YCZny5
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' %2beoH'
--- 开始 备份 ;x/.8fA
BACKUP DATABASE pubs TO testBack |_a^+!P
4、说明:创建新表 fS%B/h=
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) "Q{7X[$$^
根据已有的表创建新表: u=0161g
A:create table tab_new like tab_old (使用旧表创建新表) U?Vik
B:create table tab_new as select col1,col2... from tab_old definition only ]UZP dw1D
5、说明:删除新表 ghk"XJ|
drop table tabname }$a*XY1
6、说明:增加一个列 r/QI-Cf&
Alter table tabname add column col type 6HH:K0j3'
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。 u5`b")a
7、说明:添加主键: Alter table tabname add primary key(col) %iZ~RTY6 !
说明:删除主键: Alter table tabname drop primary key(col) qr~zTBT]
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8、说明:创建索引:create [unique] index idxname on tabname(col....) P75@Yu(
删除索引:drop index idxname *~.'lE%[U
注:索引是不可更改的,想更改必须删除重新建。 ~x J#NC+
9、说明:创建视图:create view viewname as select statement Xod/GYG
删除视图:drop view viewname Q{
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10、说明:几个简单的基本的sql语句 ,<TJh[TzC6
选择:select * from table1 where 范围 #.LI`nYA
插入:insert into table1(field1,field2) values(value1,value2) Ol;"}3*Z*
删除:delete from table1 where 范围 f^Q)lIv
更新:update table1 set field1=value1 where 范围 Q{~;4+ZD
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! "DRiJ.|APs
排序:select * from table1 order by field1,field2 [desc] B.);Ju
总数:select count as totalcount from table1 -y/Y%]%0
求和:select sum(field1) as sumvalue from table1 T6\d]
平均:select avg(field1) as avgvalue from table1 w~n+hhMF
最大:select max(field1) as maxvalue from table1 }xgs]\^,73
最小:select min(field1) as minvalue from table1 yXf+dMv
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11、说明:几个高级查询运算词 wid
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A: UNION 运算符 ]@l;;Sp
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。
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B: EXCEPT 运算符 Seq
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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。 ]DZ~"+LaG
C: INTERSECT 运算符 WqHp23
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。 1([?EfC
注:使用运算词的几个查询结果行必须是一致的。 }#nd&ND
12、说明:使用外连接 .8wF>
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A、left outer join: S=$ \S9
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。 QO4eDSW
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 =
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B:right outer join: &b]_#c
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。 }RQHsS
C:full outer join: SOS|3q_`
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。 3X9
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二、提升 jTqEV(
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) k:&B
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法一:select * into b from a where 1<>1 ]'z 5%'
法二:select top 0 * into b from a `a@YbuLd
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Ls&-8
insert into b(a, b, c) select d,e,f from b; NH'QMjL)
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) {$C"yksr
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 $$'[%
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. FyV $`c$
4、说明:子查询(表名1:a 表名2:b) GvL\%0Ibx
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) /@", 5U#
5、说明:显示文章、提交人和最后回复时间 LE g#W
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b uao#=]?)
6、说明:外连接查询(表名1:a 表名2:b) %~N| RSec
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*c3\&~,e
7、说明:在线视图查询(表名1:a ) gi8f)MNP?~
select * from (SELECT a,b,c FROM a) T where t.a > 1; C0&ZQvvy1:
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 Z|d+1i
select * from table1 where time between time1 and time2 #_: %Yd
select a,b,c, from table1 where a not between 数值1 and 数值2 WT1d'@LY
9、说明:in 的使用方法 Q6CVMYT
select * from table1 where a [not] in ('值1','值2','值4','值6') eqyUI|e
10、说明:两张关联表,删除主表中已经在副表中没有的信息 WogCt,
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) RuOse9
11、说明:四表联查问题: =r~ExW}+
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 ..... x,
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12、说明:日程安排提前五分钟提醒 \CYKj_c
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 &p55Cg@e)
13、说明:一条sql 语句搞定数据库分页 B06W(y,3Q>
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:q`KkJx
14、说明:前10条记录 nDz.61$[
select top 10 * form table1 where 范围 '.7ER
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.) W'v
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) RVr5^l;"
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 1\/^X>@W{
(select a from tableA ) except (select a from tableB) except (select a from tableC) =@d->d
17、说明:随机取出10条数据 iVb7>d9}
select top 10 * from tablename order by newid() /7WdG)'
18、说明:随机选择记录 c(s: f@ 1
select newid() @\U] hN?
19、说明:删除重复记录 $WsyAUl
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 3k:`7E.
20、说明:列出数据库里所有的表名 1#|qT7
select name from sysobjects where type='U' W O'nW
21、说明:列出表里的所有的 'lOpoWDL
select name from syscolumns where id=object_id('TableName') c']m5q39'
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 :{aiw?1
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type +O7GgySx
显示结果: <#)Q.P
type vender pcs g!`^!Q/($
电脑 A 1 sLc,Dx"+
电脑 A 1 O*>`md?MH
光盘 B 2 perhR!#J
光盘 A 2 9e;:(jl^
手机 B 3 pR!m
手机 C 3 $kxu-
23、说明:初始化表table1 j$P`/-N
TRUNCATE TABLE table1 $@~sO0q
24、说明:选择从10到15的记录 ,9$| "e&
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ?',GR aD
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三、技巧 <ti,Wn.
1、1=1,1=2的使用,在SQL语句组合时用的较多 9r 5(
"where 1=1" 是表示选择全部 "where 1=2"全部不选, <jh=W9.N_
如: SgQ(#y|vV
if @strWhere !='' FMT_X
begin * b"aJ<+
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere V%voe
end z -'e<v;w
else "!:)qVL^
begin t V2o9!N4
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' !#PA#Q|cO
end (Y
我们可以直接写成 RAA,%rRhu(
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere AH^ud*3F
2、收缩数据库 u&e?3qKX(
--重建索引 qCm8R@
DBCC REINDEX VwT&A9&{8
DBCC INDEXDEFRAG 9T<k|b[6
--收缩数据和日志 "71Y{WQ
DBCC SHRINKDB EnEaUb?P
DBCC SHRINKFILE RP9~n)h~b
3、压缩数据库 O:#/To'
dbcc shrinkdatabase(dbname) -gv[u,R
4、转移数据库给新用户以已存在用户权限 %Lp#2?*
exec sp_change_users_login 'update_one','newname','oldname' %
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go lN*"?%<x>
5、检查备份集 +^[SXI^JaJ
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Q>WnSm5R
6、修复数据库 !y3XIbdS"
ALTER DATABASE [dvbbs] SET SINGLE_USER 3o#K8EL
GO eyos6Qi
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 72= 4#
GO %Ybr5 $_
ALTER DATABASE [dvbbs] SET MULTI_USER rE?B9BF3O
GO r>t|.=!
7、日志清除 07>D G#
SET NOCOUNT ON -~
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DECLARE @LogicalFileName sysname, I:YE6${k!
@MaxMinutes INT, !4$-.L)#
@NewSize INT ]!2[k A-
USE tablename -- 要操作的数据库名 ESuP ZB
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 '2SZ]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. U}GO* +
@NewSize = 1 -- 你想设定的日志文件的大小(M) "P$')uwE
-- Setup / initialize rfV{+^T;
DECLARE @OriginalSize int B+2.:Zn6
SELECT @OriginalSize = size 2>m"CG
FROM sysfiles ;6`7
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WHERE name = @LogicalFileName Kn}Y7B{
SELECT 'Original Size of ' + db_name() + ' LOG is ' + pAyUQe;X#
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + R4S))EHg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' UK.=Y9
FROM sysfiles }S}%4c>
WHERE name = @LogicalFileName jm[f|4\
CREATE TABLE DummyTrans 0"iQHi
(DummyColumn char (8000) not null) 2nSK}q
DECLARE @Counter INT, 0SJ(Ln`0K
@StartTime DATETIME, c&"1Z/tR
@TruncLog VARCHAR(255) 9} ]C
SELECT @StartTime = GETDATE(), _OB^ywHn.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' q'%!qa+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) )2R]KU_=g
EXEC (@TruncLog) /1.gv~`+
-- Wrap the log if necessary. Kj:'Ei7
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired NFI~vkk'G
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 7Kti&T
AND (@OriginalSize * 8 /1024) > @NewSize '<AE%i,
BEGIN -- Outer loop. (mx}6A
SELECT @Counter = 0 !ozHS_
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 9 $zx<O
BEGIN -- update vyT-!mC
INSERT DummyTrans VALUES ('Fill Log') %4w#EbkSS
DELETE DummyTrans `8;\}6:"1
SELECT @Counter = @Counter + 1 R_#k^P^
END ,n$HTWa@0
EXEC (@TruncLog) 9<5ii
END P,k=u$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 1(jx.W3
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + |2I/r$Q
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' @`HW0Y_:
FROM sysfiles aQV? }
WHERE name = @LogicalFileName KD'}9{F,
DROP TABLE DummyTrans vSk1/
SET NOCOUNT OFF S0;s
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8、说明:更改某个表 }1NNXxQ
exec sp_changeobjectowner 'tablename','dbo' ;s5JYR
9、存储更改全部表 I3 YSW
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ,N8SP
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@OldOwner as NVARCHAR(128), N^jr
@NewOwner as NVARCHAR(128) Q>uJ:[x+
AS R)%I9M,
DECLARE @Name as NVARCHAR(128) kuv+ TN
DECLARE @Owner as NVARCHAR(128) 1z@{4)
DECLARE @OwnerName as NVARCHAR(128) S*H
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DECLARE curObject CURSOR FOR ,+FiP{`
select 'Name' = name, +aOX{1w
'Owner' = user_name(uid) 3*oZol/
from sysobjects m4G))||9Q
where user_name(uid)=@OldOwner K^%ONultv
order by name 4"Mq]_D
OPEN curObject svMu85z
FETCH NEXT FROM curObject INTO @Name, @Owner 'Kd-A:K2g
WHILE(@@FETCH_STATUS=0) //yz$d>JN
BEGIN COA>y?
if @Owner=@OldOwner 8aW<lu
begin vP,$S^7$
set @OwnerName = @OldOwner + '.' + rtrim(@Name) "1hFx=W+\
exec sp_changeobjectowner @OwnerName, @NewOwner y.::d9v
end `=2p6<#z
-- select @name,@NewOwner,@OldOwner _:!7M^IU
FETCH NEXT FROM curObject INTO @Name, @Owner D~ 7W
END FMC]KXSd
close curObject {G{>Qa|
deallocate curObject ]m#*4
GO [vxHsY3z
10、SQL SERVER中直接循环写入数据 ubl)$jZ:Q
declare @i int _Pn
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set @i=1 ^NO4T
while @i<30 2W;2._
begin c=p!2jJ1K~
insert into test (userid) values(@i) LVJn2t^
set @i=@i+1 VhU,("&pm
end c+:^0&l
小记存储过程中经常用到的本周,本月,本年函数 ra^"Vr
Dateadd(wk,datediff(wk,0,getdate()),-1) <BK?@Xy
Dateadd(wk,datediff(wk,0,getdate()),6)
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Dateadd(mm,datediff(mm,0,getdate()),0) p-,Bq!aG$
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) *Z3b6X'e
Dateadd(yy,datediff(yy,0,getdate()),0) 0Q[;{}W}
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) BxB B](
上面的SQL代码只是一个时间段 zEw~t&:e
Dateadd(wk,datediff(wk,0,getdate()),-1) l_zTpyOZ
Dateadd(wk,datediff(wk,0,getdate()),6) Cw~fP[5XMF
就是表示本周时间段. t_ \&LMD
下面的SQL的条件部分,就是查询时间段在本周范围内的: 5e&;f
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) %.;;itB
而在存储过程中 ^t,haO4
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ]aYuBoj
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 2h1P!4W85