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。 Z:eB9R#2y
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一、基础 Uzh#zeZ`<
1、说明:创建数据库 Z;/QB6|%
CREATE DATABASE database-name Y]!WPJ`f2
2、说明:删除数据库 O1+OE!w
drop database dbname "{9^SPsp
3、说明:备份sql server +%Z#!1u
--- 创建 备份数据的 device gpT~3c;l=
USE master Z=R 6?jU*n
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -A]-o
--- 开始 备份 '`+8'3K~E
BACKUP DATABASE pubs TO testBack l(A)G d5>
4、说明:创建新表 iy!SqC
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 2o)8 'Lp
根据已有的表创建新表: d)>b/0CZ
A:create table tab_new like tab_old (使用旧表创建新表) fM/~k>wl
B:create table tab_new as select col1,col2... from tab_old definition only L0\~K~q
5、说明:删除新表 /aV;EkyO,
drop table tabname 5]f6YlJZ
6、说明:增加一个列 ?kM2/a"{G
Alter table tabname add column col type 5nV IC3N+1
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。 M:M"7>:
7、说明:添加主键: Alter table tabname add primary key(col) Tfq7<<0$N
说明:删除主键: Alter table tabname drop primary key(col) +h]~m_O
8、说明:创建索引:create [unique] index idxname on tabname(col....) PPAcEXsIu
删除索引:drop index idxname mP*Ct6628n
注:索引是不可更改的,想更改必须删除重新建。 w`YN#G
9、说明:创建视图:create view viewname as select statement RE0ud_q2
删除视图:drop view viewname
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10、说明:几个简单的基本的sql语句 Lm&BT)*
选择:select * from table1 where 范围 l4bLN
插入:insert into table1(field1,field2) values(value1,value2) po9f[/s'+o
删除:delete from table1 where 范围 -kk0zg
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更新:update table1 set field1=value1 where 范围 Talmc|h
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! "LNLM
排序:select * from table1 order by field1,field2 [desc] *3iEO>
总数:select count as totalcount from table1 0?o<cC1Z
求和:select sum(field1) as sumvalue from table1 f/95}6M
平均:select avg(field1) as avgvalue from table1 vc%=V^)N7U
最大:select max(field1) as maxvalue from table1 [CG3&J
最小:select min(field1) as minvalue from table1 b^:frjaE3
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11、说明:几个高级查询运算词 3*zywcTH
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A: UNION 运算符 H-,p.$3}
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 XEBeoOX/
B: EXCEPT 运算符 :i3
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EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 =odK i "-6
C: INTERSECT 运算符 w8D6j%C
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 2kcDJ{(
注:使用运算词的几个查询结果行必须是一致的。 ;e{e
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12、说明:使用外连接 BgT(~8'
A、left outer join: d`UK mj
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 r$:hiE@
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 `mthzc3W
B:right outer join: wQ^RXbJI9
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。 oFb~|>d
C:full outer join: Te%V+l
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。 k4PXH
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二、提升 :6:,s#av
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) d#HlO}
法一:select * into b from a where 1<>1 x1h&`QUP
法二:select top 0 * into b from a R`J.vMT
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) G0A\"2U
insert into b(a, b, c) select d,e,f from b; ^z`d2it
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) 3bRW]mP8
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 [<|$If99\
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. q/^?rd
4、说明:子查询(表名1:a 表名2:b) Zts1BWL[
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ?bPW*A82{q
5、说明:显示文章、提交人和最后回复时间 Y(u`K=*
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9;Q|"
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6、说明:外连接查询(表名1:a 表名2:b) *xjP^y":
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c O!ilTMr
7、说明:在线视图查询(表名1:a )
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select * from (SELECT a,b,c FROM a) T where t.a > 1; v@4vitbG9
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 :='I>Gn
select * from table1 where time between time1 and time2 Z,tHyyF?j
select a,b,c, from table1 where a not between 数值1 and 数值2 "ql$Rz8
9、说明:in 的使用方法 o%!s/Z1
select * from table1 where a [not] in ('值1','值2','值4','值6') naM~>N
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~s
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) aL*}@|JL"
11、说明:四表联查问题: OIK46D6?.
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 ..... R.?PD$;_M
12、说明:日程安排提前五分钟提醒 ~Ajst!Y7=
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 3Vbt(K
13、说明:一条sql 语句搞定数据库分页 ({zWyl
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 UxxX8N
14、说明:前10条记录 cm0$v8
select top 10 * form table1 where 范围 @+0dgkJ
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.) Cmp5or6d
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =W&m{F96
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 ~{$c|
(select a from tableA ) except (select a from tableB) except (select a from tableC) M0g=gmau
17、说明:随机取出10条数据 / ykc`E?f
select top 10 * from tablename order by newid() -u7NBtgUh
18、说明:随机选择记录 qRR%aJ/
select newid() ]j!pK4
19、说明:删除重复记录 mMvAA;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %LM6=nt
20、说明:列出数据库里所有的表名 L?Ys(a"k
select name from sysobjects where type='U' ~MP |L?my
21、说明:列出表里的所有的 CG95ScrX
select name from syscolumns where id=object_id('TableName') E0x\h<6W~
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 =XtQ\$Pax
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type +$Y*1{hyOo
显示结果: h$}PQ
type vender pcs 1]9w9!j
电脑 A 1 dVk(R9 8
电脑 A 1 )dFPfu&HL
光盘 B 2 3 yw$<lm
光盘 A 2 6#AEVRJKU@
手机 B 3 'oK oF
手机 C 3 !^8X71W|
23、说明:初始化表table1 Dw.I<fns^B
TRUNCATE TABLE table1 5F!Qn\{u{
24、说明:选择从10到15的记录 hs5>Gx
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc j0j!oj)7I
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三、技巧 ,"KfZf;?
1、1=1,1=2的使用,在SQL语句组合时用的较多 '9=b@SaAj
"where 1=1" 是表示选择全部 "where 1=2"全部不选, \#xq$ygg
如: Qwt0~9n(
if @strWhere !='' ZJenwo
begin g?xD*3<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 4U_+NC>b
end 73]8NVm
else F+GX{e7E\
begin /G|v.#2/g
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }O>4XFj
end 4lWqQVx
我们可以直接写成 VdGVEDwz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ,Tu.cg
2、收缩数据库 8{QCW{K
--重建索引 #0vda'q=j
DBCC REINDEX i]N<xcF9N*
DBCC INDEXDEFRAG w@&z0ODJ
--收缩数据和日志 x=IZ0@p
DBCC SHRINKDB d:w/{m%#
DBCC SHRINKFILE gS'7:UH,
3、压缩数据库 @HiGc^X(
dbcc shrinkdatabase(dbname) wViTMlq
4、转移数据库给新用户以已存在用户权限 [*Ai@:F
exec sp_change_users_login 'update_one','newname','oldname' ?AD-n6
go 0j;ZPqEf3
5、检查备份集 (# mvDz
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' E
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6、修复数据库 ;[UI]?A%
ALTER DATABASE [dvbbs] SET SINGLE_USER e[?,'Mp9
GO :V5 Co!/+
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK BWQ`8
GO SMIDW}U2S
ALTER DATABASE [dvbbs] SET MULTI_USER m [^)Q9o}
GO .d}yQ#5z
7、日志清除 C0KFN
SET NOCOUNT ON 7Mq{Py1
DECLARE @LogicalFileName sysname, 1Ml<>
@MaxMinutes INT, +uSp3gE"
@NewSize INT mI!iSVqr
USE tablename -- 要操作的数据库名 iLIb-d?!a&
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 vPGUE`!D+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~nhO*bs}7{
@NewSize = 1 -- 你想设定的日志文件的大小(M) j~1K(=Ng
-- Setup / initialize !yPy@eP~
DECLARE @OriginalSize int ?P-O4
SELECT @OriginalSize = size e"wzb< b
FROM sysfiles <" nWGF4d
WHERE name = @LogicalFileName `kxC#
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + l?2
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + i+qg*o$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' YJMs9X~3
FROM sysfiles l"A/6r!Dp
WHERE name = @LogicalFileName Exqz$'(W9
CREATE TABLE DummyTrans 7%EIn9P
(DummyColumn char (8000) not null) wM4{\ f\
DECLARE @Counter INT, qqe"hruFJ
@StartTime DATETIME, .B-b51Uz
@TruncLog VARCHAR(255)
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SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ;akW i]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3vcyes-U
EXEC (@TruncLog) Ahl&2f\
-- Wrap the log if necessary. OblHN*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;l_b.z0^6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :e=7=|@7
AND (@OriginalSize * 8 /1024) > @NewSize =oIt.`rf
BEGIN -- Outer loop. >J3mta3
SELECT @Counter = 0 \XmplG:
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) k kAg17 ^
BEGIN -- update {q`8+$Z;
INSERT DummyTrans VALUES ('Fill Log') >n3GvZ5%
DELETE DummyTrans ]
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SELECT @Counter = @Counter + 1 V\x'w*FP
END 1t^y?<)
EXEC (@TruncLog) ?k4Hk$V
END dp^PiyL
SELECT 'Final Size of ' + db_name() + ' LOG is ' + \fEG5/s}T
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + D{Nd2G
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' eu" m0Q
FROM sysfiles m jP
WHERE name = @LogicalFileName m!G(vhA,_w
DROP TABLE DummyTrans lAM)X&}0
SET NOCOUNT OFF v5L+B`~
8、说明:更改某个表 H[p~1%Lq
exec sp_changeobjectowner 'tablename','dbo' Ar~/KRK
9、存储更改全部表 esA^-$
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch S$hxR
@OldOwner as NVARCHAR(128), I+;e#v,%U
@NewOwner as NVARCHAR(128) (E@;~7L
AS hWbu
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DECLARE @Name as NVARCHAR(128) { 22ey`@`h
DECLARE @Owner as NVARCHAR(128) y\;oZ]J
DECLARE @OwnerName as NVARCHAR(128) .<>t2,Af
DECLARE curObject CURSOR FOR ;"Qq/knVL
select 'Name' = name, _g/d/{-{Q
'Owner' = user_name(uid) 'l<$H=ZUVG
from sysobjects 0ZDm[#7z
where user_name(uid)=@OldOwner KTT!P 4
order by name BM:p)%Pv#P
OPEN curObject d*Su
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FETCH NEXT FROM curObject INTO @Name, @Owner /nA>ox78
WHILE(@@FETCH_STATUS=0) AZhI~QWo
BEGIN {'A
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if @Owner=@OldOwner yN{**?b
begin jZqa+nG51
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *\xRNgEQ
exec sp_changeobjectowner @OwnerName, @NewOwner ]~dB|WB
end 9 c9$cnQ
-- select @name,@NewOwner,@OldOwner xj U0&
FETCH NEXT FROM curObject INTO @Name, @Owner hz;SDaBA
END `Zo5!"'
close curObject jrN 5l1np
deallocate curObject *!y04'p`<
GO c^1JSGv
10、SQL SERVER中直接循环写入数据 ef{Hj[8
declare @i int *vRHF1)L
set @i=1 .Qn#wub
while @i<30 <:/aiX8
begin v"(6rZsa
insert into test (userid) values(@i) #S/~1{
set @i=@i+1 :RB7#v={
end *8a[M{-X
小记存储过程中经常用到的本周,本月,本年函数 /G7^ l>pa
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) i: UN
Dateadd(mm,datediff(mm,0,getdate()),0) C $])q`9
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) (AZneK
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Dateadd(yy,datediff(yy,0,getdate()),0) ?:60lCqj
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2BO H8Mp9
上面的SQL代码只是一个时间段 gsQn@(;
Dateadd(wk,datediff(wk,0,getdate()),-1) [7DU0Xg7
Dateadd(wk,datediff(wk,0,getdate()),6) cp8w
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就是表示本周时间段. tQ;Fgv8Y!
下面的SQL的条件部分,就是查询时间段在本周范围内的: M_E$w$l2<
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) OI)k0t^;D
而在存储过程中 0K^@P#{hd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) D&mPYxXL
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Q_,!(N