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。 m,i,n9C->
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一、基础 ,l YE
1、说明:创建数据库 Ysq'2
CREATE DATABASE database-name sV"UI
2、说明:删除数据库 g[RI.&?
drop database dbname i':ydDOOHA
3、说明:备份sql server g- AHdYJ
--- 创建 备份数据的 device
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USE master c#-U%qZ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' !U9|x\BqJ2
--- 开始 备份 B~]5$-
BACKUP DATABASE pubs TO testBack KqBk~-G
4、说明:创建新表 VVH.2&`I
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 3$.deYa$R
根据已有的表创建新表: A1'hlAGF
A:create table tab_new like tab_old (使用旧表创建新表) |8>3`w!
B:create table tab_new as select col1,col2... from tab_old definition only 1tTgP+
5、说明:删除新表 gb
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drop table tabname wO ?+Nh
6、说明:增加一个列 @SZM82qU2z
Alter table tabname add column col type F<>!kK/c
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 r.3/F[.
7、说明:添加主键: Alter table tabname add primary key(col) L
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说明:删除主键: Alter table tabname drop primary key(col) Ya>oCr}K
8、说明:创建索引:create [unique] index idxname on tabname(col....) *.L81er5~
删除索引:drop index idxname 1)
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注:索引是不可更改的,想更改必须删除重新建。 5`
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9、说明:创建视图:create view viewname as select statement G9g1hie@%
删除视图:drop view viewname W;bu2ym&Q
10、说明:几个简单的基本的sql语句 bM8If"
选择:select * from table1 where 范围 m_?d=o
插入:insert into table1(field1,field2) values(value1,value2) _ZY)M
删除:delete from table1 where 范围 ?\C"YG69T
更新:update table1 set field1=value1 where 范围 ,'[<bP'%_
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! B<j'm0a>B
排序:select * from table1 order by field1,field2 [desc] >e\9Bf_
总数:select count as totalcount from table1 3a.kBzus
求和:select sum(field1) as sumvalue from table1 :Y9NLbv
平均:select avg(field1) as avgvalue from table1 f$NM M
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最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 ml \4xp,
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11、说明:几个高级查询运算词 me[DmiM,
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A: UNION 运算符 X]\ \,
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。 :_!8
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B: EXCEPT 运算符 N<QXmgqx
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。 c478P=g=5
C: INTERSECT 运算符 CPNL
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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。 >3z5ww
注:使用运算词的几个查询结果行必须是一致的。 &u#&@J
12、说明:使用外连接 pdE3r$C
A、left outer join: ?LvCR_D:
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。 C@th O
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 xg)v0y~
B:right outer join: E<yW\
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。 jDQZQ NS
C:full outer join: MEwo}=B
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。 v4C{<8:X
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二、提升 'fW6
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1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) bV ZMW/w
法一:select * into b from a where 1<>1 zN
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法二:select top 0 * into b from a eImn+_ N3
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 0v9rv.Y"
insert into b(a, b, c) select d,e,f from b; HttiX/2~
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) `w]s;G[
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 y@\V+
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Yo[;W
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4、说明:子查询(表名1:a 表名2:b) qWmQ-|Py
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) ULQMG'P^D
5、说明:显示文章、提交人和最后回复时间 hWX% 66
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Dk?\)lD`
6、说明:外连接查询(表名1:a 表名2:b) K_dOq68_
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ~8lwe*lNV
7、说明:在线视图查询(表名1:a ) r/SG 4
select * from (SELECT a,b,c FROM a) T where t.a > 1; _-EyT
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 3YVi"
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select * from table1 where time between time1 and time2 -|E!e.^7:
select a,b,c, from table1 where a not between 数值1 and 数值2 OoWyPdC+P
9、说明:in 的使用方法 .k,kTr$S
select * from table1 where a [not] in ('值1','值2','值4','值6') )I3NeKWz
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<N nV
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) EVoEszR
11、说明:四表联查问题: TYy.jFT-
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 ..... V{JAB]?^
12、说明:日程安排提前五分钟提醒 6L)%T02C
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `QXErw
13、说明:一条sql 语句搞定数据库分页 :s4p/*f
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 b,CaWg
14、说明:前10条记录 WL'P)lI5
select top 10 * form table1 where 范围 o
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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.) I
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ra
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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 V3"=w&2]K
(select a from tableA ) except (select a from tableB) except (select a from tableC) xP [n
17、说明:随机取出10条数据 /n>qCuw
select top 10 * from tablename order by newid() M%@ !cW
18、说明:随机选择记录 p`l0?^r
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select newid() o_'p3nD
19、说明:删除重复记录 8O38#{[S
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 78/Zk}I]
20、说明:列出数据库里所有的表名 9]@A]p!
select name from sysobjects where type='U' d+'p@!W_
21、说明:列出表里的所有的 ariLG [:X
select name from syscolumns where id=object_id('TableName') nJo`B4'U
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。 NUp<e%zB
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 %@u;5qD&
显示结果: QDu 2?EYZq
type vender pcs
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电脑 A 1 uXKERzg
电脑 A 1 <TP=oq?I/
光盘 B 2 #W|'1
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光盘 A 2 R=|{n'n$0|
手机 B 3 ;1a~pF S
手机 C 3 l?Ya"C`FL
23、说明:初始化表table1 BW"5Aj
TRUNCATE TABLE table1 C_7+a@?B
24、说明:选择从10到15的记录 6b:tyQ
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ia MUsa{
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三、技巧 <>8WQn,K
1、1=1,1=2的使用,在SQL语句组合时用的较多 c`o7d)_Ke
"where 1=1" 是表示选择全部 "where 1=2"全部不选, }b-g*dn]5
如: ~x|F)~:0=
if @strWhere !='' uH(f$A
begin s{$(*_
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere D ^x-^6^
end w/kt3Lw
else ](s'L8(x
begin 6*3.SGUY
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' RS^lKJ1 U
end L>3x9
我们可以直接写成 hy`?E6=9+
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere gy_>`16K
2、收缩数据库 /\hzb/
--重建索引 HbxL:~:}J
DBCC REINDEX 7eiV{ tYF
DBCC INDEXDEFRAG D/Mi^5H)
--收缩数据和日志 *#C+iAF|)'
DBCC SHRINKDB lk( }-
DBCC SHRINKFILE v~^{{O
3、压缩数据库 $GTU$4u
dbcc shrinkdatabase(dbname) fe9LEM8j
4、转移数据库给新用户以已存在用户权限 [Ki0b^
exec sp_change_users_login 'update_one','newname','oldname' -&-Ma,M?
go +>r/ 0b
5、检查备份集 c\Q7"!e
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' SF>c\eTtx
6、修复数据库 c5u@pvSP
ALTER DATABASE [dvbbs] SET SINGLE_USER i ~{Ufi
GO Ac<Phy-J
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK LL3#5AA"k|
GO "*Tb"
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ALTER DATABASE [dvbbs] SET MULTI_USER vuoQz\
GO hBBUw0"
7、日志清除 6,0_)O}\b
SET NOCOUNT ON 5.MGaU^Z$
DECLARE @LogicalFileName sysname, 6BCf:mqP
@MaxMinutes INT, CW,Wx: Y
@NewSize INT DKBSFm{~Q
USE tablename -- 要操作的数据库名 <=>=.kmGt
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 L:i-BI`J
@MaxMinutes = 10, -- Limit on time allowed to wrap log. (EI;"N (x
@NewSize = 1 -- 你想设定的日志文件的大小(M) c1E'$-
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-- Setup / initialize 6x%h6<#xh*
DECLARE @OriginalSize int |\7
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SELECT @OriginalSize = size :>Ay^{vf=
FROM sysfiles -}KC=,]vh
WHERE name = @LogicalFileName SN1}xR$
SELECT 'Original Size of ' + db_name() + ' LOG is ' + n\^Tq<] a
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + N19({0+i2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' <y?r!l=Am
FROM sysfiles /\4'ddGU
WHERE name = @LogicalFileName C,v(:ZE$J7
CREATE TABLE DummyTrans vy\RcP
(DummyColumn char (8000) not null) .8by"?**
DECLARE @Counter INT, *tK\R&4,4s
@StartTime DATETIME, 5) pj]S!]-
@TruncLog VARCHAR(255) Z)SY.iK.
SELECT @StartTime = GETDATE(), s]f6/x/~
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY'
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0sfr d
EXEC (@TruncLog) Yi$vg
-- Wrap the log if necessary. B Z?.D_bu
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired #?/<
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ' <@3i[M
AND (@OriginalSize * 8 /1024) > @NewSize SUU !7Yd|
BEGIN -- Outer loop. N _86t
SELECT @Counter = 0 H*$jc\
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) d'G0m9u2
BEGIN -- update 5
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INSERT DummyTrans VALUES ('Fill Log') ]zWon~
DELETE DummyTrans 4X+ifZO
SELECT @Counter = @Counter + 1 Y07ZB'K
END '.81zpff
EXEC (@TruncLog) SAyufLEv,
END V0P>YQq9s
SELECT 'Final Size of ' + db_name() + ' LOG is ' + kNobl
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + _s .G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' v5QqS8u_C
FROM sysfiles 2AO~HxF
WHERE name = @LogicalFileName JYW)uJ
DROP TABLE DummyTrans .K p
SET NOCOUNT OFF c+hQSm|bf)
8、说明:更改某个表 paD !Z0v&
exec sp_changeobjectowner 'tablename','dbo' 7r~~Y%=C|
9、存储更改全部表 Lcg)UcB-#
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch -T[lx\}
@OldOwner as NVARCHAR(128), yL2o}ZbS
@NewOwner as NVARCHAR(128)
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AS 0a-0Y&lQm
DECLARE @Name as NVARCHAR(128) y"H*%]
DECLARE @Owner as NVARCHAR(128) /Z@tv.f
DECLARE @OwnerName as NVARCHAR(128) UHTvCc
DECLARE curObject CURSOR FOR *fn*h[pV&
select 'Name' = name, W8KDX_vGJ
'Owner' = user_name(uid) 4<lRPsvgc
from sysobjects Wb?8j M
where user_name(uid)=@OldOwner [Z}9>~m
order by name $D|e>U
OPEN curObject T<55a6NoK
FETCH NEXT FROM curObject INTO @Name, @Owner 4DL) rkO
WHILE(@@FETCH_STATUS=0)
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BEGIN woD>!r>)
if @Owner=@OldOwner j ~1B|,H
begin Zf65`K3
set @OwnerName = @OldOwner + '.' + rtrim(@Name) NqDHCI
exec sp_changeobjectowner @OwnerName, @NewOwner =[@zF9
end 3 G`aHTWk
-- select @name,@NewOwner,@OldOwner z6w3"9Um
FETCH NEXT FROM curObject INTO @Name, @Owner ).sRv6/c
END a{qM2P(S
close curObject ZI 3Nq
deallocate curObject .`4{9?bR
GO g!+|I
10、SQL SERVER中直接循环写入数据 + EGD.S{
declare @i int w(/aiV
set @i=1 #w\~&0
while @i<30 YQ6f}O
begin S'_-G;g.
insert into test (userid) values(@i) 7:)n$,31FW
set @i=@i+1 s3R(vd
end %sX$nmi3
小记存储过程中经常用到的本周,本月,本年函数 =p=rg$?
Dateadd(wk,datediff(wk,0,getdate()),-1) d\
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Dateadd(wk,datediff(wk,0,getdate()),6) Fpa_qjL;
Dateadd(mm,datediff(mm,0,getdate()),0) :F{:Z*Fi0
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ;I}kQ!q
Dateadd(yy,datediff(yy,0,getdate()),0) 5`gQ~
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) e0T34x'
上面的SQL代码只是一个时间段 vfE6Ggz
Dateadd(wk,datediff(wk,0,getdate()),-1) ysQ,)QoiR{
Dateadd(wk,datediff(wk,0,getdate()),6) f-E("o
就是表示本周时间段. ~,5gUl?Il
下面的SQL的条件部分,就是查询时间段在本周范围内的: 5[YDZ7g"~
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) fM^qQM[lG
而在存储过程中 PSZL2iGj9V
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) NR5oIKP?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) qx4I_%