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。 =v=H{*dWA
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一、基础 T<ekDhlr
1、说明:创建数据库 ]b@:?DX8
CREATE DATABASE database-name (( Wq
2、说明:删除数据库 F}#=qBa[
drop database dbname t`A5wqm
3、说明:备份sql server qd?k#Gw&
--- 创建 备份数据的 device {7o|*M
USE master [2ZZPY9?Q
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' HLDg_ On8
--- 开始 备份 _l.kbfp@
BACKUP DATABASE pubs TO testBack `
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4、说明:创建新表 wmgKh)`@_{
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 0CUUgwA/
根据已有的表创建新表: 5nG$6Hw
A:create table tab_new like tab_old (使用旧表创建新表) 7o64|@ 'j
B:create table tab_new as select col1,col2... from tab_old definition only ZD]5"oHY
5、说明:删除新表 ,u<aKae
drop table tabname E+E.z?>S
6、说明:增加一个列 |Ok1E
Alter table tabname add column col type ; +]GyDgVq
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 JxLD}$I
7、说明:添加主键: Alter table tabname add primary key(col) Nc :>]
说明:删除主键: Alter table tabname drop primary key(col) .e%B'
8、说明:创建索引:create [unique] index idxname on tabname(col....) D|!^8jHj
删除索引:drop index idxname zLLe3?8:
注:索引是不可更改的,想更改必须删除重新建。 ]#x?[F
9、说明:创建视图:create view viewname as select statement B(dq$+4
删除视图:drop view viewname LP:C9Ol\
10、说明:几个简单的基本的sql语句 !/MHD
选择:select * from table1 where 范围 m.N/g,
插入:insert into table1(field1,field2) values(value1,value2) 0sKY;(
删除:delete from table1 where 范围 Z"G@I= Q(
更新:update table1 set field1=value1 where 范围 KA$l.6&d
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! p)=Fi}#D\
排序:select * from table1 order by field1,field2 [desc] Y vjRJ
总数:select count as totalcount from table1 bi[gyl#
求和:select sum(field1) as sumvalue from table1 c>RS~/Y
平均:select avg(field1) as avgvalue from table1 ~*h` ?A0
最大:select max(field1) as maxvalue from table1 h+h`0(z
最小:select min(field1) as minvalue from table1 iw^(3FcP@C
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11、说明:几个高级查询运算词 i<nUp1r(
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A: UNION 运算符 fhp][)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。 ~;0J4hR
B: EXCEPT 运算符 pV^hZ.
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。 `7zNVYur8
C: INTERSECT 运算符 /xRPQ|
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。 ?Y#0Je
注:使用运算词的几个查询结果行必须是一致的。 ,-*oc>
12、说明:使用外连接 ZKa.MBde
A、left outer join: ef=LPCi?
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。 VZ8HnNAbX
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 Ni[2 p
B:right outer join: @cZNoD
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。 Yxt`Uvc(^h
C:full outer join: SD^6ib/]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。 xI7;(o"
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二、提升 :kDHwYv$
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) RHGs(d7-
法一:select * into b from a where 1<>1 QNH5Cq;Y
法二:select top 0 * into b from a tA2I_WCl
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) -\!"Kz/
insert into b(a, b, c) select d,e,f from b; N8|
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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) ',yY
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 fhAK^@h
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. jnuovM!x~
4、说明:子查询(表名1:a 表名2:b) fN TPW]
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) :8bz+3p
5、说明:显示文章、提交人和最后回复时间 sC Fqz[I
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 8L<GAe
6、说明:外连接查询(表名1:a 表名2:b) YRYAQj/7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c cM;&$IjCt
7、说明:在线视图查询(表名1:a ) ^L(}c O
select * from (SELECT a,b,c FROM a) T where t.a > 1; iS^IqS
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 /CAi%UH,F
select * from table1 where time between time1 and time2 S&@uY#_(*T
select a,b,c, from table1 where a not between 数值1 and 数值2 xhIC["z5
9、说明:in 的使用方法 KN;b+`x;M
select * from table1 where a [not] in ('值1','值2','值4','值6') hYW<4{Gjr
10、说明:两张关联表,删除主表中已经在副表中没有的信息 DM%4V|F"
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) PZRm.vC)k
11、说明:四表联查问题: b:nHcxDU<
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 ..... i#
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12、说明:日程安排提前五分钟提醒 <5Jp2x#
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 0'm4
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13、说明:一条sql 语句搞定数据库分页 WX}"Pj/6
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 47xJ(yO
14、说明:前10条记录 ~'e/lX9g-
select top 10 * form table1 where 范围 gNO<`9q
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.) 0FFx
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) E{*~>#+
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 <[2]p\rj
(select a from tableA ) except (select a from tableB) except (select a from tableC) eM*@zo<-
17、说明:随机取出10条数据 j|&?BBa9
select top 10 * from tablename order by newid() m1X0stFRs"
18、说明:随机选择记录 H1'`*
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select newid() ~bCn%r2
19、说明:删除重复记录 L
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) n;0bVVMV
20、说明:列出数据库里所有的表名 3n/U4fn_
select name from sysobjects where type='U' Wm
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21、说明:列出表里的所有的 I%43rdoPe
select name from syscolumns where id=object_id('TableName') tdn[]|=
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。 *ws!8-)fH
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 ;N4b~k)
显示结果: [{ak&{R,9{
type vender pcs :cmfy6h]
电脑 A 1 8 Vj]whE
电脑 A 1 h*f=
光盘 B 2 -bK# &o,
光盘 A 2 h:3`e`J<h
手机 B 3 HPAd@5d(
手机 C 3 vIrLG1EK
23、说明:初始化表table1 C
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TRUNCATE TABLE table1 /I3#WUc;![
24、说明:选择从10到15的记录 MC!K7ji
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4Wq{ch
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三、技巧 !Re/W
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1、1=1,1=2的使用,在SQL语句组合时用的较多 ,>n 4
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, z)'dDM D"
如: hSc$Sa8
if @strWhere !='' b<qv
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begin ysfR@ sH7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere <D4.kM
end ?w1_.m|8u
else m&DDz+g
begin 2Av3.u8%u
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `?PZvGi
end P. P3/,
我们可以直接写成 '}*5ee](S
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere rp.S4;=Q 9
2、收缩数据库 |lIkmW{
--重建索引 ~a8J"Wh
DBCC REINDEX yOGaW~
DBCC INDEXDEFRAG KL!k'4JNY
--收缩数据和日志 P8e1J0A
DBCC SHRINKDB W?!(/`J]
DBCC SHRINKFILE W{l+_a{/9
3、压缩数据库 MN|y5w}$u
dbcc shrinkdatabase(dbname) lDNB0Ad
4、转移数据库给新用户以已存在用户权限 @c{=:kg5
exec sp_change_users_login 'update_one','newname','oldname' VkT8l4($X<
go o(w1!spA
5、检查备份集 Y'-BKZv!
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ^:K"Tv.=
6、修复数据库 Z mF}pa,gd
ALTER DATABASE [dvbbs] SET SINGLE_USER O,ZvV3
GO %-|Po:6
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 2"C'Au
GO LWc}j`Wd
ALTER DATABASE [dvbbs] SET MULTI_USER _r5Q%8J
GO 59O;`y0
7、日志清除 WEUr;f
SET NOCOUNT ON d:O>--$_tw
DECLARE @LogicalFileName sysname, ^ q @.yL
@MaxMinutes INT, ZVJbpn<lo)
@NewSize INT /] ce?PPC
USE tablename -- 要操作的数据库名 _CPe
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 "-kb=fY
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Z$Ynar
@NewSize = 1 -- 你想设定的日志文件的大小(M) Y4}!9x
-- Setup / initialize D{h1"q
DECLARE @OriginalSize int dC_L~ }=
SELECT @OriginalSize = size 'Zf_/y
FROM sysfiles e|+U7=CK
WHERE name = @LogicalFileName ;Aiuy{<
SELECT 'Original Size of ' + db_name() + ' LOG is ' + |x2>F
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 0]{h,W3]@[
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' @"-<m|lM
FROM sysfiles %xf6U>T
WHERE name = @LogicalFileName oJR0sbikP
CREATE TABLE DummyTrans IP$^)t[
(DummyColumn char (8000) not null) ~" B0P>7
DECLARE @Counter INT, xA#B1qbw
@StartTime DATETIME, 4hg]/X"H#
@TruncLog VARCHAR(255) (1%u`#5n-N
SELECT @StartTime = GETDATE(), /sH3Rk.>
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' &@c=$+#C
DBCC SHRINKFILE (@LogicalFileName, @NewSize) p-UACMN&c
EXEC (@TruncLog) W+&ZYN'E
-- Wrap the log if necessary. ]x?9lQ1&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired D|,d_W
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) V{@<Z8sW#
AND (@OriginalSize * 8 /1024) > @NewSize xZjD(e'
BEGIN -- Outer loop. {Lb NKjn
SELECT @Counter = 0 fzRzkn:=
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) tQbDP!,A*=
BEGIN -- update ?C//UN;
INSERT DummyTrans VALUES ('Fill Log') ||cG/I&,
DELETE DummyTrans P*T'R
SELECT @Counter = @Counter + 1 Q1IN@Db}y
END 6 DD^h:*>
EXEC (@TruncLog) 2BBGJE
END <g5Btwo%
SELECT 'Final Size of ' + db_name() + ' LOG is ' + @3c5"
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' "wmQ,=
FROM sysfiles 41mg:xW(J
WHERE name = @LogicalFileName b[?6/#N
DROP TABLE DummyTrans /d9I2~}B
SET NOCOUNT OFF kWc%u-_
8、说明:更改某个表 #QQ\xj
exec sp_changeobjectowner 'tablename','dbo' QQ!%lbMK]
9、存储更改全部表 hAHl+q)w?
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch bKYLBu:
@OldOwner as NVARCHAR(128), [Oe$E5qv)]
@NewOwner as NVARCHAR(128) uz".!K[,wE
AS %YM4x!6
DECLARE @Name as NVARCHAR(128) -RVwPY
DECLARE @Owner as NVARCHAR(128) .6+j&{WNo!
DECLARE @OwnerName as NVARCHAR(128) *qj @y'1\
DECLARE curObject CURSOR FOR 4Z"DF)+}
select 'Name' = name, !m^;Apuy
'Owner' = user_name(uid) s\1h=V)!H
from sysobjects 7gfNe kr~W
where user_name(uid)=@OldOwner q-eC=!#}
order by name k/=J<?h0
OPEN curObject .%<oy"_
FETCH NEXT FROM curObject INTO @Name, @Owner X{P_HCd
WHILE(@@FETCH_STATUS=0) ez&v"J
BEGIN Kjc"K36{L
if @Owner=@OldOwner \$T
begin )t9<cJ=
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2PE|4zG
exec sp_changeobjectowner @OwnerName, @NewOwner 'W3>lAPx!
end _)O1v%]"4
-- select @name,@NewOwner,@OldOwner 9xyj,;P>
FETCH NEXT FROM curObject INTO @Name, @Owner +^Eruv+F
END ?P,z^
close curObject ;RB]awE
deallocate curObject (Ybc~M)z
GO iKN~fGRc
10、SQL SERVER中直接循环写入数据 Mi,yg=V
declare @i int D5Wo e&g,
set @i=1 $FZ~]Ef
while @i<30 &Vg+n0
begin Q}d6+ C
insert into test (userid) values(@i) $Lv,e\]
set @i=@i+1 7f#e#_sM;
end fQ=Yf ?b
小记存储过程中经常用到的本周,本月,本年函数 E#v}//
Dateadd(wk,datediff(wk,0,getdate()),-1) z4b2t}
Dateadd(wk,datediff(wk,0,getdate()),6) rQ(Aj
Dateadd(mm,datediff(mm,0,getdate()),0) 3ox%1x NA
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) I!dA{INN
Dateadd(yy,datediff(yy,0,getdate()),0) G)]'>m<y
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .C$S
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上面的SQL代码只是一个时间段 wUW^
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Dateadd(wk,datediff(wk,0,getdate()),-1) rS\j9@=Y4
Dateadd(wk,datediff(wk,0,getdate()),6) fPZt*A__
就是表示本周时间段. 0z #'=XWk
下面的SQL的条件部分,就是查询时间段在本周范围内的: )."_i64
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 6x)7=_:0
而在存储过程中 CeSr~Ikg|
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ynvU$}w ~'
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m.pB]yq&