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。 WA qINLdX
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一、基础 AX INThJ
1、说明:创建数据库 ]|@^1we
CREATE DATABASE database-name JJnH%Q
2、说明:删除数据库 <q836]aaA
drop database dbname \wZe] G%S
3、说明:备份sql server jdN`mosJ
--- 创建 备份数据的 device YUb_y^B^
USE master RCrCs
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ;a/E42eN;
--- 开始 备份 :0/7, i
BACKUP DATABASE pubs TO testBack #4:?gfIj
4、说明:创建新表 o-\[,}T)M
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) `^vE9nW7
根据已有的表创建新表: km(Po}
A:create table tab_new like tab_old (使用旧表创建新表) Wqnc{oq|$
B:create table tab_new as select col1,col2... from tab_old definition only Sz~OX6L
5、说明:删除新表 PnTu
drop table tabname wzA$'+Mb
6、说明:增加一个列 [^)g%|W
Alter table tabname add column col type OI*H,Z"
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。
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7、说明:添加主键: Alter table tabname add primary key(col) y-k.U%
说明:删除主键: Alter table tabname drop primary key(col) [0of1eCSl
8、说明:创建索引:create [unique] index idxname on tabname(col....) v19-./H^
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删除索引:drop index idxname 4*L_)z&4;
注:索引是不可更改的,想更改必须删除重新建。 x2EUr,7
9、说明:创建视图:create view viewname as select statement -=="<0c
删除视图:drop view viewname +vH4MwG$.&
10、说明:几个简单的基本的sql语句 J,hCvm
选择:select * from table1 where 范围 mw!F{pw
插入:insert into table1(field1,field2) values(value1,value2) PCvWS.{
删除:delete from table1 where 范围 !if
更新:update table1 set field1=value1 where 范围 <%d>v-=B
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! [GR;?R5
排序:select * from table1 order by field1,field2 [desc] IPk4
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总数:select count as totalcount from table1 .H|-_~Yx|
求和:select sum(field1) as sumvalue from table1 *|0 -~u%q
平均:select avg(field1) as avgvalue from table1 j.Hf/vi`z
最大:select max(field1) as maxvalue from table1 +0&/g&a\R
最小:select min(field1) as minvalue from table1 eDMO]5}Ht
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11、说明:几个高级查询运算词 ^ c<Ve'-
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A: UNION 运算符 !Ee:o"jG{
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。 A<{{iBEI`
B: EXCEPT 运算符 d~H`CrQE*
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。 ?}0 ,o.
C: INTERSECT 运算符 |N2#ItBbW
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。 Za9qjBH
注:使用运算词的几个查询结果行必须是一致的。 tYS06P^<
12、说明:使用外连接 KHme&yMq
A、left outer join: ]`K2N
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。 `Oa
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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 ~ a:
B:right outer join: Oz95
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。 Pal=F0-Q\
C:full outer join: NOva'qk
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。 %Zi} MPx
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二、提升 \~W'v3:W
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) oxs#866x
法一:select * into b from a where 1<>1 cr3^6HB
法二:select top 0 * into b from a @5FQX
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) u_enqC3
insert into b(a, b, c) select d,e,f from b; b;n[mk
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) J zl6eo[;
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,F|f. 7;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. p2eGm-Erq
4、说明:子查询(表名1:a 表名2:b) HtFDlvdy]
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) Vksuu@cch
5、说明:显示文章、提交人和最后回复时间 F%|h;+5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b D~m*!w*
6、说明:外连接查询(表名1:a 表名2:b) }7Uoh(d
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c lN@o2QX
7、说明:在线视图查询(表名1:a ) ^!d3=}:0
select * from (SELECT a,b,c FROM a) T where t.a > 1; iTwm3V
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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 ;pAK_>
select * from table1 where time between time1 and time2 GOPfXtkC
select a,b,c, from table1 where a not between 数值1 and 数值2 ;p//QJB9
9、说明:in 的使用方法 _)8s'MjA:&
select * from table1 where a [not] in ('值1','值2','值4','值6') jp,4h4C^)
10、说明:两张关联表,删除主表中已经在副表中没有的信息 K0~rN.C!0
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 9w"*y#_
11、说明:四表联查问题: OXA7w.^
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 ..... *wearCPeJ
12、说明:日程安排提前五分钟提醒 TOt dUO
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 F8=+j_UGI
13、说明:一条sql 语句搞定数据库分页 By|4m
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 .Mbz3;i0
14、说明:前10条记录 l#o
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select top 10 * form table1 where 范围 @{Q4^'K"
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.) S[gx{Bxiw
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 7#XzrT]
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 {c'lhUB
(select a from tableA ) except (select a from tableB) except (select a from tableC) ]Ze1s02(
17、说明:随机取出10条数据 \e*]Ls#jS
select top 10 * from tablename order by newid() 0kh6@y3
18、说明:随机选择记录 M%HU4pTW#o
select newid() q~3>R=t
19、说明:删除重复记录 ye&;(30Oq
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) G{}VPcrbC
20、说明:列出数据库里所有的表名 @JMiO^
select name from sysobjects where type='U' C+$#y2"z#n
21、说明:列出表里的所有的 P:c w|Q
select name from syscolumns where id=object_id('TableName') M3\AY30L
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 79gT+~z
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type N8jIMb'<
显示结果: <~)P7~$d?p
type vender pcs k[xSbs'D
电脑 A 1 HPl<%%TI
电脑 A 1 [0!( xp^
光盘 B 2 01]f2.5
光盘 A 2 d{?LD?,)
手机 B 3 us-L]S+lm
手机 C 3 j#|ZP-=1_
23、说明:初始化表table1 -@'FW*b
TRUNCATE TABLE table1 Lbgi7|&
24、说明:选择从10到15的记录 Wr
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc XFl6M~ c
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三、技巧 X'ag)|5ot
1、1=1,1=2的使用,在SQL语句组合时用的较多 #qki
"where 1=1" 是表示选择全部 "where 1=2"全部不选, y29m/i:
如: IGl9g_18
if @strWhere !='' M`_0C38
begin i!Ba]n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [agMfn
end ,tFg4k[
else YK_7ip.a[
begin )~>YH*g
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' L(-4w+
end 00(\ZUj
我们可以直接写成 VY-EmbkG-t
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 6ujWNf
2、收缩数据库 I9^x,F"E]
--重建索引 &oNAv-m^GD
DBCC REINDEX Z,gk|M3.
DBCC INDEXDEFRAG F9^S"qv$
--收缩数据和日志 E.h*g8bXe
DBCC SHRINKDB 0GwR~Z}Z
DBCC SHRINKFILE 6tZI["\
3、压缩数据库 Qs!5<)6
dbcc shrinkdatabase(dbname) w0.
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4、转移数据库给新用户以已存在用户权限 + {]j]OP
exec sp_change_users_login 'update_one','newname','oldname' WJi]t9 3
go "+c-pO`Wg
5、检查备份集 4g/dP^
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' mpyt5#f
6、修复数据库 C!gZN9-
ALTER DATABASE [dvbbs] SET SINGLE_USER Ry&6p>-
GO tbr=aY$jY
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK X}]-*T|a
GO R2NZ{"h
ALTER DATABASE [dvbbs] SET MULTI_USER 6Wn1{v0
GO 4+n\k
7、日志清除 ;uW FHc5@B
SET NOCOUNT ON ib m4fa
DECLARE @LogicalFileName sysname, }p
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@MaxMinutes INT, /r 5eWR1G
@NewSize INT y =@N|f!
USE tablename -- 要操作的数据库名 4H/OBR
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 SbZ6t$"
@MaxMinutes = 10, -- Limit on time allowed to wrap log. )b)z m2;
@NewSize = 1 -- 你想设定的日志文件的大小(M) /v }`l
-- Setup / initialize *8q.YuZ
DECLARE @OriginalSize int +ZYn? #IQ
SELECT @OriginalSize = size !D6]JPX
FROM sysfiles qs6aB0ln
WHERE name = @LogicalFileName 3|7QUld
SELECT 'Original Size of ' + db_name() + ' LOG is ' + `cO:<^%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 4i bc
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' xw%0>K[
FROM sysfiles 7)m9"InDI
WHERE name = @LogicalFileName 1C.VnzRnJ
CREATE TABLE DummyTrans :UdF
(DummyColumn char (8000) not null) }Z>)DN=+
DECLARE @Counter INT, `oJ [u:b
@StartTime DATETIME, 2%1hdA<
@TruncLog VARCHAR(255) rqq1TRg
SELECT @StartTime = GETDATE(), :k"]5>(^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Dq xs+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) s2?&!
EXEC (@TruncLog) L];b<*d
-- Wrap the log if necessary. Ac6=(B
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired %y@AA>x!
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ysN3
AND (@OriginalSize * 8 /1024) > @NewSize 2c}E(8e]
BEGIN -- Outer loop. 9uY'E'm*
SELECT @Counter = 0 <3iMRe
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 0(Ij%Wi,
BEGIN -- update $'TM0Yu,
INSERT DummyTrans VALUES ('Fill Log') 49P4b<1
DELETE DummyTrans
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SELECT @Counter = @Counter + 1 GILfbNcd
END }G=M2V<L
EXEC (@TruncLog) 9L9sqZUB
END TC. ,V_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + (hsl~Jf
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )"LJ
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' m|# y
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FROM sysfiles NI5``BwpO
WHERE name = @LogicalFileName j pOp.
DROP TABLE DummyTrans PFR:>^wK2
SET NOCOUNT OFF 0V]s:S
8、说明:更改某个表 l%ZhA=TKQ
exec sp_changeobjectowner 'tablename','dbo' tkhCw/
9、存储更改全部表 IID5c"
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )Z$!PqRw@u
@OldOwner as NVARCHAR(128), 67TwPvh
@NewOwner as NVARCHAR(128) +(*DT9s+
AS Si,6o!0k
DECLARE @Name as NVARCHAR(128) {*KEP
DECLARE @Owner as NVARCHAR(128) ?upM>69{
DECLARE @OwnerName as NVARCHAR(128) H]!"Zq k
DECLARE curObject CURSOR FOR 598i^z{~0%
select 'Name' = name, Al'3?
'Owner' = user_name(uid) ZuIefMiG~+
from sysobjects uEYtE7
where user_name(uid)=@OldOwner \9d$@V
order by name u>$t'
OPEN curObject X8|EHb<
FETCH NEXT FROM curObject INTO @Name, @Owner
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WHILE(@@FETCH_STATUS=0) `6YN3XS
BEGIN K^$=dLp
if @Owner=@OldOwner ':W[ A
begin HDKbF/
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ] - .aL
exec sp_changeobjectowner @OwnerName, @NewOwner b[yiq$K/
end 7rA;3?p)
-- select @name,@NewOwner,@OldOwner 8Y3I0S
FETCH NEXT FROM curObject INTO @Name, @Owner y]imZ4{/
END Wm|lSisY
close curObject "ta x?
deallocate curObject R3!t$5HG
GO jal-9NV)!
10、SQL SERVER中直接循环写入数据 HThcn1u~^b
declare @i int ~Z+%d9ode
set @i=1 KG@8RtHsQ
while @i<30 8f7>?BUS,
begin |3%8&@ho
insert into test (userid) values(@i) 7|D +Ihy;
set @i=@i+1 {[(h[MW#
end OTp]Xe/
小记存储过程中经常用到的本周,本月,本年函数 fV:83|eQ
Dateadd(wk,datediff(wk,0,getdate()),-1) .o8t+X'G
Dateadd(wk,datediff(wk,0,getdate()),6) X|[`P<'N<
Dateadd(mm,datediff(mm,0,getdate()),0) iUwzs&frd
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) m4& /s
Dateadd(yy,datediff(yy,0,getdate()),0) fLVAKn
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Mlq.?-QgIL
上面的SQL代码只是一个时间段 mt`.6Xz~
Dateadd(wk,datediff(wk,0,getdate()),-1) h$=2 p5'-
Dateadd(wk,datediff(wk,0,getdate()),6) 8[>zG2
就是表示本周时间段. W`&hp6Jq
下面的SQL的条件部分,就是查询时间段在本周范围内的: L(o15
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) e*!kZAf
而在存储过程中 V,9cl,z+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 3[&C g
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Mq8L0%j