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。 o C|oh
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一、基础 &233QRYM
1、说明:创建数据库 nUj`#%
CREATE DATABASE database-name 0L/chP
2、说明:删除数据库 ]\^O(BzB
drop database dbname " YI,
3、说明:备份sql server Y_[7q<L
--- 创建 备份数据的 device Im~DK
USE master ]?(kaNQ"D
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ^ l#6Es
--- 开始 备份 3&})gU&a
BACKUP DATABASE pubs TO testBack ];w}?LFb
4、说明:创建新表 aC}\`.Kb
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ZJ%NZAxy
根据已有的表创建新表: cS%dTrfo
A:create table tab_new like tab_old (使用旧表创建新表) hdw.S`~}%
B:create table tab_new as select col1,col2... from tab_old definition only q~> +x?30
5、说明:删除新表 eAW)|=2
drop table tabname 3zh:~w_
6、说明:增加一个列 [Ep'm
Alter table tabname add column col type =i vlS
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。
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7、说明:添加主键: Alter table tabname add primary key(col) A4f"v)vM
说明:删除主键: Alter table tabname drop primary key(col) @Pcgm"H<
8、说明:创建索引:create [unique] index idxname on tabname(col....) zp8x/,gwF
删除索引:drop index idxname #,z-Pj?O!
注:索引是不可更改的,想更改必须删除重新建。 Ac U@H0
9、说明:创建视图:create view viewname as select statement wuXQa
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删除视图:drop view viewname j.] ]VA
10、说明:几个简单的基本的sql语句 K*5gb^Ul
选择:select * from table1 where 范围 c"tlNf?
插入:insert into table1(field1,field2) values(value1,value2) L~PiDQr?r
删除:delete from table1 where 范围 wb62($
更新:update table1 set field1=value1 where 范围 !$l<'K$
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ~v(c9I)
排序:select * from table1 order by field1,field2 [desc] 7u;N/@
总数:select count as totalcount from table1 05H:ZrUV
求和:select sum(field1) as sumvalue from table1 /#vt\I<x
平均:select avg(field1) as avgvalue from table1 nmiJ2edx
最大:select max(field1) as maxvalue from table1 ;MGm,F,o
最小:select min(field1) as minvalue from table1 H_f8/H
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11、说明:几个高级查询运算词 .iR<5.
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A: UNION 运算符 Ut2T:%m{
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。 qZ!kVrmg&
B: EXCEPT 运算符 @>(JC]HtR
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。 U<&=pv
C: INTERSECT 运算符 H^kOwmSzh
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。 O$,
注:使用运算词的几个查询结果行必须是一致的。 X[h{g`
12、说明:使用外连接 })]
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A、left outer join: TY%c`Q5
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 g8E5"jpXx3
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c a^LckHPI>
B:right outer join: ZB1%Kn#zo4
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 `scW.Vem
C:full outer join: N<SW
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全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 qnyacI
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二、提升 OP+*%$wR
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) %|x9C,0p#
法一:select * into b from a where 1<>1 .BJoY
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法二:select top 0 * into b from a 3(K.:376
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 4I&(>9 @z<
insert into b(a, b, c) select d,e,f from b; .Bkfe{^
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) l4$ sku-
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Eg1TF oIWl
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ??e|ec2%
4、说明:子查询(表名1:a 表名2:b) (&79}IEd
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) .*6NqX$
5、说明:显示文章、提交人和最后回复时间 'eBD/w5U
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ~roNe|P
6、说明:外连接查询(表名1:a 表名2:b)
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c '%/=\Q`
7、说明:在线视图查询(表名1:a ) y(<{e~
select * from (SELECT a,b,c FROM a) T where t.a > 1; AVLY|79#
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 >|RoLV
select * from table1 where time between time1 and time2 "Ai\NC
select a,b,c, from table1 where a not between 数值1 and 数值2 &V
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9、说明:in 的使用方法 vbJdhaf
select * from table1 where a [not] in ('值1','值2','值4','值6') 8aHE=x/TL
10、说明:两张关联表,删除主表中已经在副表中没有的信息 U*{0, Ue'
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) J#H,QYnf(L
11、说明:四表联查问题: q'7.lrKwa>
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 ..... lFf>z}eLy
12、说明:日程安排提前五分钟提醒 ;yqHt!N
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ';\norx;
13、说明:一条sql 语句搞定数据库分页 k;<@2C
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 lE%KzX?&
14、说明:前10条记录 H/`@6, j
select top 10 * form table1 where 范围 A-m IWTa
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.) wKdWE`|y
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) e~*tQ4
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 n&&C(#mBC
(select a from tableA ) except (select a from tableB) except (select a from tableC) :Nf(:D8
17、说明:随机取出10条数据 unFm~rcf
select top 10 * from tablename order by newid() U.Vn|s(`z
18、说明:随机选择记录 5h Sd,#:
select newid() #s(ob `0|
19、说明:删除重复记录 AXxyB"7A}
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) WU=EJY}#n
20、说明:列出数据库里所有的表名 kz}Bc
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select name from sysobjects where type='U' #k/T\PQ0s
21、说明:列出表里的所有的 78:x{1nUM[
select name from syscolumns where id=object_id('TableName') 6qmV/DL
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。 ^PE|BCs
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 Q;l%@)m+~
显示结果: '`gnJX
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type vender pcs uj\&-9gEi
电脑 A 1 V/DMkO#a
电脑 A 1 cGo_qR/B(>
光盘 B 2 qp*~|
光盘 A 2 v1+.-hO
手机 B 3 JXww_e[
手机 C 3 "fv+}'
23、说明:初始化表table1 IDF0nx]
TRUNCATE TABLE table1 E0HE@pqr
24、说明:选择从10到15的记录 LZG(T$dI
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc !s$1C=z5u
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三、技巧 CD#U`jf
1、1=1,1=2的使用,在SQL语句组合时用的较多 F@ pf._c
"where 1=1" 是表示选择全部 "where 1=2"全部不选, K&{ _s
如: UWqiA`,
if @strWhere !='' +3AX1o%p,#
begin QTF1~A\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere -f:PgBj
end GHLFn~z@XJ
else L{;Q6_m
begin BuAzO>=
set @strSQL = 'select count(*) as Total from [' + @tblName + ']'
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end "p+oi@
我们可以直接写成 iM9k!u FE
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere xrY >Or
2、收缩数据库 c>c4IQ&d
--重建索引 >e.vUUQ{
DBCC REINDEX yXtQfR
DBCC INDEXDEFRAG E*tT^x)
--收缩数据和日志 2|1CGHj\
DBCC SHRINKDB &'DR`e O)
DBCC SHRINKFILE 9T$%^H9
3、压缩数据库 fpZHE=}r
dbcc shrinkdatabase(dbname) A=ez,87
4、转移数据库给新用户以已存在用户权限 #ax% n
exec sp_change_users_login 'update_one','newname','oldname' )eSQce7H
go |V}tTx1
5、检查备份集 ?qHQ#0 @y]
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' =<#++;!I
6、修复数据库 S}Z@g
ALTER DATABASE [dvbbs] SET SINGLE_USER 6v}q @z
GO T8*;?j*@
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK o9Mr7
GO i(e=
ALTER DATABASE [dvbbs] SET MULTI_USER 4u0?[v[Hu
GO n^55G>"0|
7、日志清除
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SET NOCOUNT ON j~+(#|
DECLARE @LogicalFileName sysname, [*C~BM
@MaxMinutes INT, ox.kL
@NewSize INT |yj0Rv
USE tablename -- 要操作的数据库名 wwR}h I(
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ]<%NX
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. gd%Ho8,T
@NewSize = 1 -- 你想设定的日志文件的大小(M) |Q%nnN
-- Setup / initialize C!v%6[
DECLARE @OriginalSize int BGH'&t_5
SELECT @OriginalSize = size 1B 0[dK2N
FROM sysfiles wLfH/J
WHERE name = @LogicalFileName zrE{CdG%y
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 6"[,
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \|]+sQ WQ
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 6I_4{
FROM sysfiles "9 vL+Hh
WHERE name = @LogicalFileName FKf2Q&2I
CREATE TABLE DummyTrans L&|^y8
(DummyColumn char (8000) not null) ycIcM~<4
DECLARE @Counter INT, '['x'G50
@StartTime DATETIME, ?d3<GhzlR3
@TruncLog VARCHAR(255) @,G\`;Ma
SELECT @StartTime = GETDATE(), 66MUrNW
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Q!AGalP z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) v`qXb$YW
EXEC (@TruncLog) ET*:iioP
-- Wrap the log if necessary. NOAz"m+o
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired $.ctlWS8l{
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) NQOf\.#g
AND (@OriginalSize * 8 /1024) > @NewSize cxPO O#
BEGIN -- Outer loop. f&Sovuuh
SELECT @Counter = 0 G ,`]2'(@
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ']^]z".H
BEGIN -- update }1a(*s,s-^
INSERT DummyTrans VALUES ('Fill Log') r'*#i>PkQD
DELETE DummyTrans M,r8 No
SELECT @Counter = @Counter + 1 NXS$w{^
END +QSH*(,
EXEC (@TruncLog) +}mj;3i
END W:}t%agis
SELECT 'Final Size of ' + db_name() + ' LOG is ' + e?GzvM'2
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + DoN]v
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' \SJX;7ST
FROM sysfiles K'K/}q<
WHERE name = @LogicalFileName 2c*}1
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DROP TABLE DummyTrans szOa yAS
SET NOCOUNT OFF {yxLL-5c
8、说明:更改某个表 Iq{/-,v
exec sp_changeobjectowner 'tablename','dbo' <c,iu{:
9、存储更改全部表 zvv/|z2(r
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch & TN.6Hm3
@OldOwner as NVARCHAR(128), Hm~.u.)\.
@NewOwner as NVARCHAR(128) {3Dm/u%=9|
AS Yqt~h
DECLARE @Name as NVARCHAR(128) -(#`JT8
DECLARE @Owner as NVARCHAR(128) ,L\KS^>
DECLARE @OwnerName as NVARCHAR(128) 9S5C{~P4
DECLARE curObject CURSOR FOR O4^' H}*
select 'Name' = name, b:
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'Owner' = user_name(uid) tCj\U+;
from sysobjects |uJjO>8]|
where user_name(uid)=@OldOwner nbDjoZZ4
order by name !Okl3
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OPEN curObject ny<D1>{90
FETCH NEXT FROM curObject INTO @Name, @Owner M'NOM>8
WHILE(@@FETCH_STATUS=0) &o`LT|*m
BEGIN P (fWJVF7
if @Owner=@OldOwner j}G9+GX~,
begin 8K\S]SZ
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ogdgLTi
exec sp_changeobjectowner @OwnerName, @NewOwner - C8VDjf9
end Pf3F)y [=
-- select @name,@NewOwner,@OldOwner {J;(K~>?m
FETCH NEXT FROM curObject INTO @Name, @Owner 8&7zV:=
END AbX#wpp!
close curObject
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deallocate curObject +4[Je$qYa
GO 0.U-
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10、SQL SERVER中直接循环写入数据 J[\8:qE
declare @i int E8aD[j[w
set @i=1 ~x+&cA-0A2
while @i<30 &i*e&{L7
begin B\~(:(OPM]
insert into test (userid) values(@i) QC1\Sn /
set @i=@i+1 0"mr*hyj
end ]];LA!n
小记存储过程中经常用到的本周,本月,本年函数 IKp/xj[!
Dateadd(wk,datediff(wk,0,getdate()),-1) mU>lm7'
Dateadd(wk,datediff(wk,0,getdate()),6) 78IY&q:v&0
Dateadd(mm,datediff(mm,0,getdate()),0) ]1q`N7
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) #V@vz#bo=
Dateadd(yy,datediff(yy,0,getdate()),0) 1E$^ul-v
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) V'l9fj*E
上面的SQL代码只是一个时间段 "Q[?W(SA
Dateadd(wk,datediff(wk,0,getdate()),-1) ;F/w&u.n
Dateadd(wk,datediff(wk,0,getdate()),6) }l5Q0'
就是表示本周时间段. ~yY5pnJ
下面的SQL的条件部分,就是查询时间段在本周范围内的: {w v{"*Q9Q
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) i~{ 0>"9
而在存储过程中 85:mh\@-G
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) suN}6CI
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 'lgS;ItpKu