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。 }C1wfZ~F~
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一、基础 u'1=W5$rK
1、说明:创建数据库 T7~v40jn|
CREATE DATABASE database-name j.}V~Sp*
2、说明:删除数据库 auW]rwY
drop database dbname JrTBe73.]j
3、说明:备份sql server 5#\p>}[HG
--- 创建 备份数据的 device F4%[R)
USE master 55b |zf
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 8-ssiiJ}gh
--- 开始 备份 8v
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BACKUP DATABASE pubs TO testBack #UD
4、说明:创建新表 sLp
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) gDNW~?/
根据已有的表创建新表: J9.p8A^^2
A:create table tab_new like tab_old (使用旧表创建新表) &X,)+b=
B:create table tab_new as select col1,col2... from tab_old definition only nF$)F?||
5、说明:删除新表 vPNZFi-(
drop table tabname s'Gy+h.
6、说明:增加一个列 #!,`EU
Alter table tabname add column col type UO<claV
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。 d<? :Q
7、说明:添加主键: Alter table tabname add primary key(col) em!R9J.
说明:删除主键: Alter table tabname drop primary key(col) >%dAqYi $
8、说明:创建索引:create [unique] index idxname on tabname(col....) ldvxYq<:
删除索引:drop index idxname {; cB?II
注:索引是不可更改的,想更改必须删除重新建。 t~K!["g
9、说明:创建视图:create view viewname as select statement 7h/Q;P5
删除视图:drop view viewname Yj/nzTVJ[
10、说明:几个简单的基本的sql语句 +/86w59
选择:select * from table1 where 范围 x>"JWD
插入:insert into table1(field1,field2) values(value1,value2) p!QneeA`&X
删除:delete from table1 where 范围 k]9> V@C
更新:update table1 set field1=value1 where 范围 )ZyuF(C&
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! YPDsE&,J)
排序:select * from table1 order by field1,field2 [desc] @SG"t,5s
总数:select count as totalcount from table1 Nw&}qSN
求和:select sum(field1) as sumvalue from table1 aq/Y}s?
平均:select avg(field1) as avgvalue from table1 g4SYG)'R+
最大:select max(field1) as maxvalue from table1 ]m#MwN$
最小:select min(field1) as minvalue from table1 xjq7%R_,
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11、说明:几个高级查询运算词 8 E+C:"
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A: UNION 运算符 VD&3%G!
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。 ?[1qC=[Z<
B: EXCEPT 运算符 15T[J%7f
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。 G$|;~'E
C: INTERSECT 运算符 UQ?OD~7
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 [67E5rk-
注:使用运算词的几个查询结果行必须是一致的。 6 %k+0\d
12、说明:使用外连接 :`^3MMLO
A、left outer join: bKJ7vXC05
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 yO,`"Dc_0
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c S<]a@9W
B:right outer join: 4'hcHdL9
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ig_<kj;Vd
C:full outer join: OPt;G,$ta
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。 IgR"euU
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二、提升 =<zSF\Zr_
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 3?Eoj95w!
法一:select * into b from a where 1<>1 $gl<{{
法二:select top 0 * into b from a $#ju?B~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) SP?U@w%}
insert into b(a, b, c) select d,e,f from b; chMc(.cN0
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) fDEu%fUYZ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }Wche/g`
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ]v\egfW,W
4、说明:子查询(表名1:a 表名2:b) j5h
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) dJ%Rk#?;A
5、说明:显示文章、提交人和最后回复时间 1mVVPt^6
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b FJ(B]n[>
6、说明:外连接查询(表名1:a 表名2:b) oYh<k
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c [+MX$y
7、说明:在线视图查询(表名1:a ) Xz.Y-5)
select * from (SELECT a,b,c FROM a) T where t.a > 1; mV*/zWh_
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 8u'O`j
select * from table1 where time between time1 and time2 =6:L +V
select a,b,c, from table1 where a not between 数值1 and 数值2 T<e7(=
9、说明:in 的使用方法 d:<H?~
select * from table1 where a [not] in ('值1','值2','值4','值6') MjXE|3&
10、说明:两张关联表,删除主表中已经在副表中没有的信息 hN_f h J
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Am4^v?q
11、说明:四表联查问题: Q6!v3P/h
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 ..... 6;[/9
12、说明:日程安排提前五分钟提醒 M |({
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %w8GGm8^/
13、说明:一条sql 语句搞定数据库分页 _:Jp*z
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 71.\`'
14、说明:前10条记录 oAZF3h]po
select top 10 * form table1 where 范围 lHKf#|
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.) -?YT Q@ W
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) z'oiyXEE3
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 ){
(select a from tableA ) except (select a from tableB) except (select a from tableC) }uI7\\S
17、说明:随机取出10条数据 ./&zO{|0]
select top 10 * from tablename order by newid() 7.e7Fi{
18、说明:随机选择记录 Vl 19Md
select newid() 95^i/6Gl!P
19、说明:删除重复记录 ZG@M%|>
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) VwOG?5W/
20、说明:列出数据库里所有的表名 puS&S
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select name from sysobjects where type='U' m
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21、说明:列出表里的所有的 =0PRAc
select name from syscolumns where id=object_id('TableName') w &|R5Q
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。 "o{)X@YN]
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 x* =sRf
显示结果: y3cf[Q
type vender pcs )b&-3$?
电脑 A 1 GT'7,+<?N
电脑 A 1 Zv| p>q`R2
光盘 B 2 0939i_
光盘 A 2 hH1lgc
手机 B 3 EzIs@}
手机 C 3 sCF40AoY&
23、说明:初始化表table1 -!|WZ
TRUNCATE TABLE table1 6hM]%
24、说明:选择从10到15的记录 .B'UQ|NR
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 7Y32p'
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三、技巧 ss`P QN
1、1=1,1=2的使用,在SQL语句组合时用的较多 -*|:v67C&
"where 1=1" 是表示选择全部 "where 1=2"全部不选, /BMtcCPG!
如: ms}f>f=
if @strWhere !='' @GG(7r\/B
begin V \6(d
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere /Fe:h>6
end e2k4[V
else 79SqYe=&uy
begin @n7t?9Bx
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' L\ }Pzxn
end )d +hZ'
我们可以直接写成 U!c]_q
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere a#+>w5
2、收缩数据库 Bf5&}2u
--重建索引 b4Cfd?'
DBCC REINDEX d/B'[Ur
DBCC INDEXDEFRAG _)KY
--收缩数据和日志 dh^+l;!L
DBCC SHRINKDB Q PFeBl
DBCC SHRINKFILE <t{?7_ 8
3、压缩数据库 s) Cpi
dbcc shrinkdatabase(dbname) JBR[;
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4、转移数据库给新用户以已存在用户权限 'ySljo*It
exec sp_change_users_login 'update_one','newname','oldname' ~n[b^b
go =s'XR@
5、检查备份集 &:V@2_6"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' -B1YZ/.rz"
6、修复数据库 U_}7d"<| ?
ALTER DATABASE [dvbbs] SET SINGLE_USER B(j02<-
GO 8F zHNG
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ~->Hlxze'K
GO #(%t*"IY;
ALTER DATABASE [dvbbs] SET MULTI_USER )n7|?@5U
GO |l|_dn
7、日志清除 9W*.lf
SET NOCOUNT ON V43nws"4
DECLARE @LogicalFileName sysname, 3{<R5wUo"
@MaxMinutes INT, E'5Ajtw;
@NewSize INT UvkJ?Bu
USE tablename -- 要操作的数据库名 1GtOA3,~;-
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 07x=`7hs}
@MaxMinutes = 10, -- Limit on time allowed to wrap log. j$@?62)6
@NewSize = 1 -- 你想设定的日志文件的大小(M) [@m[V1D
-- Setup / initialize F`!TV(,bY
DECLARE @OriginalSize int 1~%o}+#-
SELECT @OriginalSize = size ,e9CJ~a
FROM sysfiles u8Y~_)\MA
WHERE name = @LogicalFileName '#v71,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + mCM|&u
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [2Iau1<@
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' tbq|,"
FROM sysfiles Ko#4z%Yq
WHERE name = @LogicalFileName z!fdx|PUX
CREATE TABLE DummyTrans u(W^Nou/+
(DummyColumn char (8000) not null) c~P)4(udT
DECLARE @Counter INT, W_^>MLq
@StartTime DATETIME, ajW[eyX
@TruncLog VARCHAR(255) nV'3sUvR#
SELECT @StartTime = GETDATE(), [#p&D~Du&
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' HOE2*4r
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ibvJWg
EXEC (@TruncLog) {G]?{c)"
-- Wrap the log if necessary. Qi_&aU$>lM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired {|s/]W
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) >):m-I
AND (@OriginalSize * 8 /1024) > @NewSize \}Dpb%^\
BEGIN -- Outer loop. D%-{q>F!gf
SELECT @Counter = 0 tqK=\{U
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) D9~}5
BEGIN -- update OCCEL9d
INSERT DummyTrans VALUES ('Fill Log') EYG"49
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DELETE DummyTrans TMK'(6dH
SELECT @Counter = @Counter + 1 yI8 SQ$w0y
END =f>HiF
EXEC (@TruncLog) B={/nC}G~
END kl"
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + -Q#o)o
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + HOfF"QAR$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' O@s{uZ|A6
FROM sysfiles Q:mZ" i5
WHERE name = @LogicalFileName sGSsUO:@j;
DROP TABLE DummyTrans @%c81rv?
SET NOCOUNT OFF j")FaIM
8、说明:更改某个表 [OzzL\)3l
exec sp_changeobjectowner 'tablename','dbo' 9qpU@V!
9、存储更改全部表 !#?8BwnaZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch O}QFq14<+
@OldOwner as NVARCHAR(128), 6*Zj]is
@NewOwner as NVARCHAR(128) ! a o6e
AS ~ FGe~
DECLARE @Name as NVARCHAR(128) D}w<84qX
DECLARE @Owner as NVARCHAR(128) n12UBvc}%
DECLARE @OwnerName as NVARCHAR(128) W2`.RF^
DECLARE curObject CURSOR FOR 7,*%[#-HE
select 'Name' = name, >V(zJ
'Owner' = user_name(uid) |Ab{H%
from sysobjects SET-8f
where user_name(uid)=@OldOwner Txo@U
order by name c5("-xB
OPEN curObject iX%[YQ |
FETCH NEXT FROM curObject INTO @Name, @Owner [EgW/\35
WHILE(@@FETCH_STATUS=0) g5y;?fqJ
BEGIN UFe(4]^
if @Owner=@OldOwner [Eu];
begin ltoqtB\s
set @OwnerName = @OldOwner + '.' + rtrim(@Name) #|Oj]bd(=
exec sp_changeobjectowner @OwnerName, @NewOwner nd:E9:
end #zt*xS[{0
-- select @name,@NewOwner,@OldOwner Y9u;H^^G
FETCH NEXT FROM curObject INTO @Name, @Owner )Vg2Jix,]
END gz;&u)
close curObject "mOI!xf@a
deallocate curObject x`2| }AP(
GO `}gdN};
10、SQL SERVER中直接循环写入数据 !2$ z *C2;
declare @i int %k2FPmA6
set @i=1 dCe X}Z
while @i<30 /Wu |)tx
begin U'y,YtF@
insert into test (userid) values(@i) :I
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set @i=@i+1 @DuK#W"E u
end hL!QLiF:
小记存储过程中经常用到的本周,本月,本年函数 zmiZ]uq
Dateadd(wk,datediff(wk,0,getdate()),-1) tiYOMA
Dateadd(wk,datediff(wk,0,getdate()),6) vZu~LW@1
Dateadd(mm,datediff(mm,0,getdate()),0) G`F8!O(
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "~/9F
Dateadd(yy,datediff(yy,0,getdate()),0) RPH1''*!
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \3zp)J
上面的SQL代码只是一个时间段 rQJ"&CapT
Dateadd(wk,datediff(wk,0,getdate()),-1) K"\MU
Dateadd(wk,datediff(wk,0,getdate()),6) Hm
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就是表示本周时间段. wzh]97b
下面的SQL的条件部分,就是查询时间段在本周范围内的: GX?*1
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Km!nM$=k
而在存储过程中 J -V49X#
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) "'a* [%
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ]\Xc9N8w