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。 ,Vax&n+J
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一、基础 0> E r=,e
1、说明:创建数据库 rXq.DvQ
CREATE DATABASE database-name c#]4awHU
2、说明:删除数据库 ?R
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drop database dbname @4C% +-
3、说明:备份sql server qkqIV^*R
--- 创建 备份数据的 device Q\vpqE!9
USE master zI uJ-8T"
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' =%O6:YM
--- 开始 备份 fbvL7*
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BACKUP DATABASE pubs TO testBack ~=LE0. 3[
4、说明:创建新表 hE/cd1iJ$
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ) q4[zv9
根据已有的表创建新表: ?UR0:f:}oc
A:create table tab_new like tab_old (使用旧表创建新表) ty!`T+3
B:create table tab_new as select col1,col2... from tab_old definition only Qel9G($=
5、说明:删除新表 hZ,_6mNg
drop table tabname I
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6、说明:增加一个列 a-tmq]]E
Alter table tabname add column col type |-ALklXr
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。 Rv>-4@fMJ
7、说明:添加主键: Alter table tabname add primary key(col) t}4,]ms
说明:删除主键: Alter table tabname drop primary key(col) Yh7t"=o
8、说明:创建索引:create [unique] index idxname on tabname(col....) KF}hV9IU
删除索引:drop index idxname Dy&i&5E.-l
注:索引是不可更改的,想更改必须删除重新建。 = svN#q5s
9、说明:创建视图:create view viewname as select statement ~8+ Zs
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 >R_&Ouh:
选择:select * from table1 where 范围 J)>c9w
插入:insert into table1(field1,field2) values(value1,value2) _LnpnL:
删除:delete from table1 where 范围 . Efk*
更新:update table1 set field1=value1 where 范围 (WJRi:NP?
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 'Is kWgc
排序:select * from table1 order by field1,field2 [desc] y^*~B(T{
总数:select count as totalcount from table1 %;'s4ly
求和:select sum(field1) as sumvalue from table1 o-HT1Hc!
平均:select avg(field1) as avgvalue from table1 ^\% (,KNo
最大:select max(field1) as maxvalue from table1 8,%^
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最小:select min(field1) as minvalue from table1 gJ{)-\
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11、说明:几个高级查询运算词 J;e2&gB
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A: UNION 运算符 j (d~aqW
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。 "k@/3
B: EXCEPT 运算符 \)[j_^
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。 & .j&0WE
C: INTERSECT 运算符 ^ytrK
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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。 o|:b;\)b
注:使用运算词的几个查询结果行必须是一致的。 #{6/ (X
12、说明:使用外连接 3hH<T.@)
A、left outer join: C!!M%P
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。 HC8e>kP9b
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 J@'wf8Ub
B:right outer join: ITBE|b
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。 CRE3icXbQ
C:full outer join: e !Y~Qy
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。 0OE:[pR
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二、提升 Kc-W&?~y#1
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ~
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法一:select * into b from a where 1<>1 ~!L}yw
法二:select top 0 * into b from a 7$=InK
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 2ilQXy
insert into b(a, b, c) select d,e,f from b; tWRC$
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) oc`H}Wvn
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 IJ"q~r$
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. H
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4、说明:子查询(表名1:a 表名2:b) o*H<KaX
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) R 9\*#c
5、说明:显示文章、提交人和最后回复时间 K%oG,-wdg
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b L4HI0Mx
6、说明:外连接查询(表名1:a 表名2:b) wHy!CP%
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c R/YqyT\SM
7、说明:在线视图查询(表名1:a ) i/4>2y9/F4
select * from (SELECT a,b,c FROM a) T where t.a > 1; e7 o.xR
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_%_ x*
select * from table1 where time between time1 and time2 W6Fo6a"<
select a,b,c, from table1 where a not between 数值1 and 数值2 &u
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9、说明:in 的使用方法 *2l7f`K
select * from table1 where a [not] in ('值1','值2','值4','值6') (9a^$C*
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ~DwpoeYX
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) zDG b7S{
11、说明:四表联查问题: !Uo4,g6r+
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 ..... h_'*XWd@
12、说明:日程安排提前五分钟提醒 2>%=U~5
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 QXK{bxwC
13、说明:一条sql 语句搞定数据库分页 75lA%|
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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 {l@{FUv
14、说明:前10条记录 'g\4O3&_
select top 10 * form table1 where 范围 W>r+h-kR
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.) /n&&Um\
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~n_HP_Kf?
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 wCBplaojJ
(select a from tableA ) except (select a from tableB) except (select a from tableC) !N^@4*
17、说明:随机取出10条数据 :A;RH
select top 10 * from tablename order by newid()
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18、说明:随机选择记录 dZuOrTplA
select newid() sI2^Qp@O1
19、说明:删除重复记录 KI.hy2?e
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <P<z N~i9j
20、说明:列出数据库里所有的表名 [-w%/D%@
select name from sysobjects where type='U' X?Q4} Y
21、说明:列出表里的所有的 i|kRK7[6B
select name from syscolumns where id=object_id('TableName') ca9X19NG
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。 bN.Pex
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 &p,]w~d,U
显示结果: %C]>9."
type vender pcs ]:n,RO6
电脑 A 1 Z\sDUJ
电脑 A 1 i6Gu@( 8Q
光盘 B 2 /dHF6yW
光盘 A 2 eMzk3eOJ
手机 B 3 I/N *gy?*
手机 C 3 eO1lnO|
23、说明:初始化表table1 /9X7A;O
TRUNCATE TABLE table1 6eCCmIdaM
24、说明:选择从10到15的记录 ,!9zrYi}
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc l^}c!
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三、技巧 pR_9NfV{
1、1=1,1=2的使用,在SQL语句组合时用的较多 5zJq9\)d+
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Ys7]B9/1O
如: 'GScszz
if @strWhere !='' I1J-)R+
begin AZ<=o
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere xz]~ jL@-]
end 2 E=L8<
else ;VK.2^jW!
begin ~J]qP #C
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' qP
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end '"Nr, vQo
我们可以直接写成 ~ri5zb20
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere naNghGQ
2、收缩数据库
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--重建索引 p7~!z.)o
DBCC REINDEX 1;iUWU1@
DBCC INDEXDEFRAG ry]l.@o;
--收缩数据和日志 {8etv:y
DBCC SHRINKDB {`_i`
DBCC SHRINKFILE +T+#q@
3、压缩数据库 OTv)
dbcc shrinkdatabase(dbname) \7_y%HR
4、转移数据库给新用户以已存在用户权限 \<K5ZIWV
exec sp_change_users_login 'update_one','newname','oldname' V[V[~;Py
go {..6>fS
5、检查备份集 Ul# r
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' N>E_%]C h
6、修复数据库 D+c>F5
ALTER DATABASE [dvbbs] SET SINGLE_USER x1<|hTPk
GO 9M ]_nP Y
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK VN.Je:Ju
GO kGJC\{N5N
ALTER DATABASE [dvbbs] SET MULTI_USER }B^tL$k
GO >GuM]qn
7、日志清除 dWW.Y*339
SET NOCOUNT ON 6~+emlD
DECLARE @LogicalFileName sysname, |[lKY+26:{
@MaxMinutes INT, AFn7uW!9Gw
@NewSize INT HKe K<V
USE tablename -- 要操作的数据库名 BLFdHB.$T
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 8,|k ao:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. I 6O
@NewSize = 1 -- 你想设定的日志文件的大小(M) g{LP7D;6
-- Setup / initialize )PZT4jTt
DECLARE @OriginalSize int V~#tuv
SELECT @OriginalSize = size d=^z`nt !R
FROM sysfiles ~Gw*r\\+
WHERE name = @LogicalFileName 3XKf!P
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 1mJHued=6
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + sRfcF`7
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' c " ,*h
FROM sysfiles ,z6~?6m
WHERE name = @LogicalFileName 0`H#
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CREATE TABLE DummyTrans M\=2uKG#
(DummyColumn char (8000) not null) ,u m|1dh
DECLARE @Counter INT, DNi+"[~&P
@StartTime DATETIME, kT=8e;K
@TruncLog VARCHAR(255) lx i<F
SELECT @StartTime = GETDATE(), R#KU^]"(
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ULW~90
DBCC SHRINKFILE (@LogicalFileName, @NewSize) :KO2| v\
EXEC (@TruncLog) Va8&Z
-- Wrap the log if necessary. JS77M-Ac
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 6C)_
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) xD$\,{
AND (@OriginalSize * 8 /1024) > @NewSize .C(tMF]D,
BEGIN -- Outer loop. JI5Dy>u:
SELECT @Counter = 0 X?Au/
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) a{e4it
BEGIN -- update \NC3'G:Ii
INSERT DummyTrans VALUES ('Fill Log') Mihg:
DELETE DummyTrans P;*(hY5&
SELECT @Counter = @Counter + 1 :EyD+!LJ
END E"0>yl)
EXEC (@TruncLog) >d6| ^h'0
END adw2x pj
SELECT 'Final Size of ' + db_name() + ' LOG is ' + .(vwIb8\_
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + .V*^|UXbHi
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' EK'!}OGCG
FROM sysfiles 2pAW9R#UV-
WHERE name = @LogicalFileName v0y(58Rz.
DROP TABLE DummyTrans 0IpmRH/
SET NOCOUNT OFF r*Xuj=
8、说明:更改某个表 ;d?R:Uw8
exec sp_changeobjectowner 'tablename','dbo' F[0]/
9、存储更改全部表 ~K=b\xc^
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Mp]rUPK
@OldOwner as NVARCHAR(128), pJ{Y
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@NewOwner as NVARCHAR(128) W>LR\]Ti@
AS D,6:EV"sa
DECLARE @Name as NVARCHAR(128) t&p|Ynz?i
DECLARE @Owner as NVARCHAR(128) 7o4\oRGV
DECLARE @OwnerName as NVARCHAR(128) '<M{)?
DECLARE curObject CURSOR FOR uq{beC
select 'Name' = name, ?4B`9<j8%
'Owner' = user_name(uid) cNH7C"@GVu
from sysobjects _G0x3
where user_name(uid)=@OldOwner 54/=G(F
order by name (w{j6).3Dj
OPEN curObject %3rP`A
FETCH NEXT FROM curObject INTO @Name, @Owner -HuA
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WHILE(@@FETCH_STATUS=0) x"~JR\yzKJ
BEGIN wS*E(IAl
if @Owner=@OldOwner
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begin A=4OWV?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) /j^
exec sp_changeobjectowner @OwnerName, @NewOwner 0`hdMLONR
end 9VT;ep
-- select @name,@NewOwner,@OldOwner xkn;,`t^lJ
FETCH NEXT FROM curObject INTO @Name, @Owner v2?ZQeHr_(
END h$*!8=M
close curObject Ls%MGs9PI
deallocate curObject w(rE`IgW
GO _Y!IEAU/#
10、SQL SERVER中直接循环写入数据 y)pk6d
declare @i int }M+7T\J!
set @i=1 M?qy(zb
while @i<30 $u.z*b_yy
begin D]}G.v1
insert into test (userid) values(@i) {8OCXus3m
set @i=@i+1 M}Sv8D]I
end "oD[v
小记存储过程中经常用到的本周,本月,本年函数 36NpfTW
Dateadd(wk,datediff(wk,0,getdate()),-1) v:U-6W_)|
Dateadd(wk,datediff(wk,0,getdate()),6) 4Up/p&1@
Dateadd(mm,datediff(mm,0,getdate()),0) MJvp6n
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Vc2`b3"Br
Dateadd(yy,datediff(yy,0,getdate()),0) v1[29t<I!
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) >/|*DI-HJ
上面的SQL代码只是一个时间段 Uv.)?YeGh
Dateadd(wk,datediff(wk,0,getdate()),-1) nlYNN/@"
Dateadd(wk,datediff(wk,0,getdate()),6) OCUr{Nh
就是表示本周时间段. kl`W\t F
下面的SQL的条件部分,就是查询时间段在本周范围内的: HhpDR
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 68
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而在存储过程中 ;fJ.8C
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) TN.rrop`#g
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) /\Ef%@