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。 ZkRx1S"m
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一、基础 U\4g#!qj
1、说明:创建数据库 `#F{Waww'
CREATE DATABASE database-name g]<4&)~
2、说明:删除数据库 d6}r#\
drop database dbname D0&,?
3、说明:备份sql server Z0x ar]4V
--- 创建 备份数据的 device fi-WZ
USE master a
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' z1PBMSG
--- 开始 备份 -LK
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BACKUP DATABASE pubs TO testBack TyD4|| %
4、说明:创建新表 !"HO]3-o
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) J*yf2&lI5
根据已有的表创建新表: N..yQ-6x?
A:create table tab_new like tab_old (使用旧表创建新表) &zl|87M
B:create table tab_new as select col1,col2... from tab_old definition only 5{|7$VqPF
5、说明:删除新表 gf#{k2r
drop table tabname -BrMp%C
6、说明:增加一个列 _E &A{HkJ
Alter table tabname add column col type 8n#HFJ~
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 PWaw]*dFmy
7、说明:添加主键: Alter table tabname add primary key(col) A -H&
说明:删除主键: Alter table tabname drop primary key(col) FcR=v0),
8、说明:创建索引:create [unique] index idxname on tabname(col....) T6O::o6
删除索引:drop index idxname |% F=po>w
注:索引是不可更改的,想更改必须删除重新建。 ~P*6ozSYpY
9、说明:创建视图:create view viewname as select statement 3m]4=
删除视图:drop view viewname \8)U!9,$nn
10、说明:几个简单的基本的sql语句 lP[w?O
选择:select * from table1 where 范围 Y}t \4 di
插入:insert into table1(field1,field2) values(value1,value2) 1tEgl\u\
删除:delete from table1 where 范围 wKtl+}}
更新:update table1 set field1=value1 where 范围 kw>v:F<M
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! W]"zctE
排序:select * from table1 order by field1,field2 [desc] Tzt8h\Q^z
总数:select count as totalcount from table1 -[*,^Ti`
求和:select sum(field1) as sumvalue from table1 SN9kFFIPb=
平均:select avg(field1) as avgvalue from table1 m'Amli@[
最大:select max(field1) as maxvalue from table1 ''q@>
最小:select min(field1) as minvalue from table1 O,+1<.;+
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11、说明:几个高级查询运算词 04LI]'
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A: UNION 运算符 "Q}#^h]F
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。 ^ZvWR%
B: EXCEPT 运算符 sv: 9clJ
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。 '-r).Xk
C: INTERSECT 运算符 6LOnU~l,
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。 &vo--V1|
注:使用运算词的几个查询结果行必须是一致的。 9v;Vv0k_
12、说明:使用外连接 Od)Uv1
A、left outer join: qW$<U3u}
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 Ff$L|
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 AsQ)q
B:right outer join: ~+Rc}K
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。 R+2+-j4
C:full outer join: y~Bh
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。 n&{Dq}q
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二、提升 \kp8S'qVo
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6bomh2
法一:select * into b from a where 1<>1 X@$f$=
法二:select top 0 * into b from a j2Cks_$:
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8|):`u
insert into b(a, b, c) select d,e,f from b; > A Khf
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) $Z!`Hb
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 <>dT64R|
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. q$ZHd
4、说明:子查询(表名1:a 表名2:b) G 3+.H
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) "9m2/D`=
5、说明:显示文章、提交人和最后回复时间 2QD3&Q9
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 9i'jjN
6、说明:外连接查询(表名1:a 表名2:b) ;
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =[H;orMr
7、说明:在线视图查询(表名1:a ) 6TQoqH8@U
select * from (SELECT a,b,c FROM a) T where t.a > 1; &R[ Mc-2
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 -d~4A
select * from table1 where time between time1 and time2 FK:;e
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select a,b,c, from table1 where a not between 数值1 and 数值2 dU6ou'pf
9、说明:in 的使用方法 ,p4&g)o
select * from table1 where a [not] in ('值1','值2','值4','值6') 2"0es40;0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7FzA*
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Of-Rx/
11、说明:四表联查问题: p6]7&{>
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 ..... x^HGVWw_
12、说明:日程安排提前五分钟提醒 9*2[B"5
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 C\3y {s
13、说明:一条sql 语句搞定数据库分页 ~8~aJ^[
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 c2h{6;bfY
14、说明:前10条记录 &qMPq->
select top 10 * form table1 where 范围 M2HomO/X)
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.) iWRH{mK
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) $h5xH9x
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16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 _4rFEYz$d
(select a from tableA ) except (select a from tableB) except (select a from tableC) '[U8}z3
17、说明:随机取出10条数据 {\S+#W\
select top 10 * from tablename order by newid() m`v2: S}
18、说明:随机选择记录 #Vl 0.l3
select newid() *}]Nf
19、说明:删除重复记录 jq-p;-i
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) DQNnNsP:M-
20、说明:列出数据库里所有的表名 3
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select name from sysobjects where type='U' &%8'8,.
21、说明:列出表里的所有的 R%Qf7Q
select name from syscolumns where id=object_id('TableName') :H7D~ n
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。 "JVkVp[5D+
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 ks3`3q 7
显示结果: TMAJb+@l:
type vender pcs " W!M[qBW
电脑 A 1 XxT#X3D/,"
电脑 A 1 qd9c I&
光盘 B 2 vqnw#U4`
光盘 A 2 Ipf|")*
手机 B 3 !,l9@eJQ
手机 C 3 m#8m] Y
23、说明:初始化表table1 VGfMN|h
TRUNCATE TABLE table1 D;oe2E{I
24、说明:选择从10到15的记录 6BY-^"W5`
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc !(mjyr
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三、技巧 b_,|>U
1、1=1,1=2的使用,在SQL语句组合时用的较多 uXI_M)
"where 1=1" 是表示选择全部 "where 1=2"全部不选, X'wE7=29M
如: _9faBrzd
if @strWhere !='' 3 ,>0a
begin a#^B2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere sJ#4(r`
end /|r^W\DV&x
else =7-9[ {
begin e8y;.D[2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ~hZ"2$(0
end oE<`VY|
我们可以直接写成 Wc,_RN-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *7*lE"$p
2、收缩数据库 y#>,+a#5
--重建索引 nnCGg+l
DBCC REINDEX ~1cnE:x;V
DBCC INDEXDEFRAG $@sEn4h
--收缩数据和日志 bsuus
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DBCC SHRINKDB So{x]x:f
DBCC SHRINKFILE ?;KKw*
3、压缩数据库 lwHzj&/ ~
dbcc shrinkdatabase(dbname) +)k b(
4、转移数据库给新用户以已存在用户权限 UUSq$~Ct
exec sp_change_users_login 'update_one','newname','oldname'
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go i#7DR>XF/
5、检查备份集 WF2}-NU"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' BsBK@+ZyI
6、修复数据库 {xwm^p(f
ALTER DATABASE [dvbbs] SET SINGLE_USER 2uG0/7
GO l-K9LTd
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK cYFiJJLG]
GO j H19k}D
ALTER DATABASE [dvbbs] SET MULTI_USER MJ7 Y#<u
GO +IrLDsd
7、日志清除 aF)1Nm[
SET NOCOUNT ON GRGzP&}@
DECLARE @LogicalFileName sysname, ^sa#8^,K
@MaxMinutes INT, jL(qf~c_
@NewSize INT :Nu^
USE tablename -- 要操作的数据库名 M54j@_81pX
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 H:!7:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ;ToKJ6hN|*
@NewSize = 1 -- 你想设定的日志文件的大小(M) HuB<k3#sPy
-- Setup / initialize zEs>b(5u
DECLARE @OriginalSize int 3l)h yVf&
SELECT @OriginalSize = size ipQLK{]t
FROM sysfiles 8S>&WR%jH]
WHERE name = @LogicalFileName ([
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + `n$I]_}/%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :/y1yM
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z."a.>fPaO
FROM sysfiles bx<RV7>0
WHERE name = @LogicalFileName 6WV\}d:
CREATE TABLE DummyTrans GMMp|WV|
(DummyColumn char (8000) not null) +hn+K1
DECLARE @Counter INT, @b"t]#V(E
@StartTime DATETIME, ZPiq-q
@TruncLog VARCHAR(255) }xBc0gr
SELECT @StartTime = GETDATE(), }tsYJlh5
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' "[vu6 `m?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) y|CP;:f;
EXEC (@TruncLog) EPS={w$'s
-- Wrap the log if necessary. W.z;B<
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired lCAIK
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) yMyE s 8
AND (@OriginalSize * 8 /1024) > @NewSize 7G.#O}).b
BEGIN -- Outer loop. *&?c(JU;<
SELECT @Counter = 0 HU%o6c w
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) K/A*<<r
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BEGIN -- update 8d?g]DEN)6
INSERT DummyTrans VALUES ('Fill Log') "5;;)\o~
DELETE DummyTrans @.G[s)x
SELECT @Counter = @Counter + 1 ~7Ts_:E-
END f>aEkh6u9
EXEC (@TruncLog) jZh';M8"
END ;FBUwR}
SELECT 'Final Size of ' + db_name() + ' LOG is ' + R16'?,
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + XpmS{nb
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' bA=
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FROM sysfiles (:._"jp]
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans ktj]:rCkF
SET NOCOUNT OFF CK:y?
8、说明:更改某个表 KC(xb5x
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exec sp_changeobjectowner 'tablename','dbo' NLS%S q
9、存储更改全部表 /3eKN
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8CnRi
@OldOwner as NVARCHAR(128), an4GSL
@NewOwner as NVARCHAR(128) s4 6}s{6
AS =:D aS`~V
DECLARE @Name as NVARCHAR(128) -QOw8vm
DECLARE @Owner as NVARCHAR(128) 7h6,c /<
DECLARE @OwnerName as NVARCHAR(128) VUVaaOmO
DECLARE curObject CURSOR FOR Ynp{u`?
select 'Name' = name, ,oaw0Vw
'Owner' = user_name(uid) z74in8]
from sysobjects ~vXaqCX
where user_name(uid)=@OldOwner 4D['^q
order by name =Vy`J)z9
OPEN curObject &8%e\W\K:/
FETCH NEXT FROM curObject INTO @Name, @Owner Y]{
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WHILE(@@FETCH_STATUS=0) %6L^2
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BEGIN b8LoIY*
if @Owner=@OldOwner fQL"O}Z
begin g0>,%b
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e?_@aa9~@{
exec sp_changeobjectowner @OwnerName, @NewOwner {.Z}5K
end bhkUKxd
-- select @name,@NewOwner,@OldOwner |;.o8}
FETCH NEXT FROM curObject INTO @Name, @Owner ta`N8vnf
END Y2d;E.DH8
close curObject F#5B<I
deallocate curObject xEf'Bmebk
GO dFH$l
10、SQL SERVER中直接循环写入数据 `)GrwfC
declare @i int Cl^\OZN\=
set @i=1 FDVcow*] n
while @i<30 H2
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begin ZKQG:M~|
insert into test (userid) values(@i) L3G \
set @i=@i+1 Kv.>Vf.T}_
end .C2TQ:B, .
小记存储过程中经常用到的本周,本月,本年函数 T :/,2.l
Dateadd(wk,datediff(wk,0,getdate()),-1) Q3|T':l4
Dateadd(wk,datediff(wk,0,getdate()),6) ~_Lr=C D;4
Dateadd(mm,datediff(mm,0,getdate()),0) 9cEv&3
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) v2H#=E4cZ#
Dateadd(yy,datediff(yy,0,getdate()),0) JJ{9U(`_y6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~zSCg|"r
上面的SQL代码只是一个时间段 d?:=PH
Dateadd(wk,datediff(wk,0,getdate()),-1) O!Oumw,$
Dateadd(wk,datediff(wk,0,getdate()),6) oP!;\a( SL
就是表示本周时间段. U Z|HJ8_
下面的SQL的条件部分,就是查询时间段在本周范围内的: hGbj0
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) jM$`(Y
而在存储过程中 3t<a $i
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 3&6#F"7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6ezS {Q