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。 Kp1 F"!
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一、基础 >l/pwb@
1、说明:创建数据库 6A}tA$*s7
CREATE DATABASE database-name JnIG;/
2、说明:删除数据库 inZ0iU9dy
drop database dbname moh,a B#
3、说明:备份sql server Kv<mDA!
--- 创建 备份数据的 device Y6d~hLC
USE master v\qyDZ VV
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' fX6pW%Q'6
--- 开始 备份 m\bmBK"I
BACKUP DATABASE pubs TO testBack H{Lt,#
4、说明:创建新表 f5l\3oL
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [p}~M-$V8Y
根据已有的表创建新表: e"XolM0IM
A:create table tab_new like tab_old (使用旧表创建新表) Wm5[+z|2?9
B:create table tab_new as select col1,col2... from tab_old definition only QnS#"hc\a
5、说明:删除新表 *M0O&" ~j
drop table tabname `P-d. M6Oa
6、说明:增加一个列 W1t_P&i
Alter table tabname add column col type C dPQhv)m
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%c^j9' 1
7、说明:添加主键: Alter table tabname add primary key(col) UQ7La 7"
说明:删除主键: Alter table tabname drop primary key(col) n<<arO"cv
8、说明:创建索引:create [unique] index idxname on tabname(col....) ?~#[cx
删除索引:drop index idxname Z7[S698
注:索引是不可更改的,想更改必须删除重新建。 J^%E$s
9、说明:创建视图:create view viewname as select statement ^Jdg%U?
删除视图:drop view viewname #o9CC)q5G
10、说明:几个简单的基本的sql语句 ITi#p%
选择:select * from table1 where 范围 !|]k2=+I
插入:insert into table1(field1,field2) values(value1,value2) ,Mi'NO
删除:delete from table1 where 范围 /BvMNKb$$
更新:update table1 set field1=value1 where 范围 TcJJ"[0
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Qz%q#4Zb
排序:select * from table1 order by field1,field2 [desc] ZrA*MN
总数:select count as totalcount from table1 kM=&Tfpj
求和:select sum(field1) as sumvalue from table1 6Yt3Oq<U
平均:select avg(field1) as avgvalue from table1 NLYf
最大:select max(field1) as maxvalue from table1 x2aG5@<3
最小:select min(field1) as minvalue from table1 -f1}N|hy
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11、说明:几个高级查询运算词 \F\7*=xk
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A: UNION 运算符 v)nv"o[
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。 X}C8!LA
B: EXCEPT 运算符 .*>C[^
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。 Z?3B1o9
C: INTERSECT 运算符 m(kv:5<>
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。 R\#5;W^
注:使用运算词的几个查询结果行必须是一致的。 3pL4Zhf
12、说明:使用外连接 px+]/P<dX
A、left outer join: ,@f |t&
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。 W$J.B!O
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c _FS #~z'j
B:right outer join: nU\.`.39
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 T2)CiR-b
C:full outer join: 8oRq3 "
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Pc5C*{C
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二、提升 B>\q!dX3
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 0o BAJP
法一:select * into b from a where 1<>1 0]]OE+9<c
法二:select top 0 * into b from a ba
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) o_kZ
insert into b(a, b, c) select d,e,f from b; a\Gd;C ^`
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) Nl%5OBm
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Ukf:m&G
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 0JR)-*
4、说明:子查询(表名1:a 表名2:b) )"M;7W?R0
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) XtBEVqrhi
5、说明:显示文章、提交人和最后回复时间 R"CF xo
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `zl,|}u)
6、说明:外连接查询(表名1:a 表名2:b) g}a+%Obb
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c OPqhdqo
7、说明:在线视图查询(表名1:a ) ]iFW>N*a
select * from (SELECT a,b,c FROM a) T where t.a > 1; D@[#7:rHL
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 -HuIz6
select * from table1 where time between time1 and time2 HJpx,NU'
select a,b,c, from table1 where a not between 数值1 and 数值2 ~HT:BO$
9、说明:in 的使用方法 5xNOIOpDB
select * from table1 where a [not] in ('值1','值2','值4','值6') '@\[U0?@K
10、说明:两张关联表,删除主表中已经在副表中没有的信息 US9@/V*2
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) w+5OI9
11、说明:四表联查问题: iXXaB+w
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 ..... ,kYX|8SO
12、说明:日程安排提前五分钟提醒 bu\(KR$s
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 EqIs&){
13、说明:一条sql 语句搞定数据库分页 -qpM 6t
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 '%*hs8s
14、说明:前10条记录 6Iz!_
select top 10 * form table1 where 范围 HTMo.hr
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) \Ov~ t
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) c5O8,sT
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 7X>@r"9<
(select a from tableA ) except (select a from tableB) except (select a from tableC) X`eX+9
17、说明:随机取出10条数据 dBN:
select top 10 * from tablename order by newid() qvhG^b0h
18、说明:随机选择记录 ZGCp[2$
select newid() oq1wU@n
19、说明:删除重复记录 /;21?o
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &f?JtpB
20、说明:列出数据库里所有的表名 NxK.q)tj6
select name from sysobjects where type='U' HAs/f#zAk6
21、说明:列出表里的所有的 1L\r:mx3
select name from syscolumns where id=object_id('TableName') Py+ B 2G|
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。 q$}J/w(,
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 Ip8:~Fl]
显示结果: @j%@Z
type vender pcs ;>X;cZMd
电脑 A 1 wXBd"]G)C
电脑 A 1 CR#-!_=4
光盘 B 2 I{%(G(
光盘 A 2 ~HtD]|7
手机 B 3 JEZ0O&_R
手机 C 3 n>SK2`
23、说明:初始化表table1 ,,)'YhG(
TRUNCATE TABLE table1 $I ,Np)i
24、说明:选择从10到15的记录 P(C5@x(Z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Tpkt'|8
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三、技巧 < mFU T
1、1=1,1=2的使用,在SQL语句组合时用的较多 7nW <kA
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ^d(gC%+!u
如: .O+,1&D5
if @strWhere !='' )QnsRW{D"
begin g0;6}n
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere I_`NjJ;61
end 4`RZ&w;1H2
else -ntQqHs
begin /~+Fzz
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' (gcy3BX;
end |&bucG=
我们可以直接写成 WBzPSnS2
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere L`rrT
2、收缩数据库 Sb)}
--重建索引 5pHv5e
DBCC REINDEX V;~\+@
DBCC INDEXDEFRAG "#f5jH
--收缩数据和日志 -h8Z@r~a/
DBCC SHRINKDB 6D{70onY+
DBCC SHRINKFILE uX1{K%^<TW
3、压缩数据库 ,eqRI>,\
dbcc shrinkdatabase(dbname) X?`mYoe
4、转移数据库给新用户以已存在用户权限 Hbu
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exec sp_change_users_login 'update_one','newname','oldname' ;oVOq$ql
go aouYPxA`
5、检查备份集 wg:\$_Og
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' v9t'CMU
6、修复数据库 PVmePgF
ALTER DATABASE [dvbbs] SET SINGLE_USER "`Xbi/i
GO x{rjngp2
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK V%zo[A
GO 0B~x8f
ALTER DATABASE [dvbbs] SET MULTI_USER c<q~T >0k
GO N7X(gh2h
7、日志清除 ,hT**(W
SET NOCOUNT ON xz+;1JAL3
DECLARE @LogicalFileName sysname, {q~N$"#
@MaxMinutes INT, ~1S,[5u|s
@NewSize INT F
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USE tablename -- 要操作的数据库名 mFd|JbW
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 5,Co(K
@MaxMinutes = 10, -- Limit on time allowed to wrap log. jz\>VYi(7
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,bB}lU)
-- Setup / initialize plNw>rFa
DECLARE @OriginalSize int {?3i^Q=V
SELECT @OriginalSize = size Vk76cV
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FROM sysfiles N7;kWQH
WHERE name = @LogicalFileName rQPO+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + X|R"8cJ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + ,wyEo>>4)
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' wDBU+Z
FROM sysfiles m?;/H
WHERE name = @LogicalFileName Q7mikg=1-
CREATE TABLE DummyTrans ZA'0q
(DummyColumn char (8000) not null) -KqMSf&9
DECLARE @Counter INT, hN!{/Gc|
@StartTime DATETIME, ^j1G08W
@TruncLog VARCHAR(255) Gxt6]+r
SELECT @StartTime = GETDATE(), !4YmaijeN
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' P(LiH
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 0]GenT"
EXEC (@TruncLog) y'^b{q@
-- Wrap the log if necessary. /<o?T{z<-
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired FJW,G20L
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) i&)OJy
AND (@OriginalSize * 8 /1024) > @NewSize }L^PZS@Jf
BEGIN -- Outer loop. aHNn!9#1
SELECT @Counter = 0 E*+]Iq1u
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) v,iq,p)&
BEGIN -- update )R"UX:Q>
INSERT DummyTrans VALUES ('Fill Log') zzT4+wy`
DELETE DummyTrans ,V;HMF.
SELECT @Counter = @Counter + 1 &m TYMpA
END $]^Io)}f@
EXEC (@TruncLog) 5R1?jlm
END (Q.I DDlr
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }|znQ3A2\l
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + :G5O_T$
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5mm&l+N)
FROM sysfiles A3.pz6iT>
WHERE name = @LogicalFileName 1h{7dLA
DROP TABLE DummyTrans 5/HkhTyj
SET NOCOUNT OFF QS-X_
8、说明:更改某个表 /In=u6D O
exec sp_changeobjectowner 'tablename','dbo' Nlu]f-i':
9、存储更改全部表 t^~itlE{
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch r[2*K 9
@OldOwner as NVARCHAR(128), 0}g~69Z1=
@NewOwner as NVARCHAR(128) T?7++mcA
AS t\n'Kuk`
DECLARE @Name as NVARCHAR(128) &NI\<C7_Gw
DECLARE @Owner as NVARCHAR(128) }CrWmJu0
DECLARE @OwnerName as NVARCHAR(128) i=V2
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DECLARE curObject CURSOR FOR jk%H+<FU`
select 'Name' = name, ')(U<5y)
'Owner' = user_name(uid) acj-*I
from sysobjects 3u,B<
where user_name(uid)=@OldOwner [-R[rF
order by name `SS[[FT$>
OPEN curObject >U]KPL[%
FETCH NEXT FROM curObject INTO @Name, @Owner WkPT6d
WHILE(@@FETCH_STATUS=0) ._&SS,I5VZ
BEGIN LO38}w<k
if @Owner=@OldOwner Y&$puiH-j
begin LK>;\BRe?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &Cr4<V6-q
exec sp_changeobjectowner @OwnerName, @NewOwner Z55C4F5v
end _k(&<1i
-- select @name,@NewOwner,@OldOwner ]?Q<lMG
FETCH NEXT FROM curObject INTO @Name, @Owner >g{b'Xx
END p>W@h*[6w
close curObject pLMaXX~4_
deallocate curObject 9N6 \Ou~
GO )C rsm&
10、SQL SERVER中直接循环写入数据 9)4_@rf%
declare @i int jQ-2SA O
set @i=1 +Y>oNX1KN
while @i<30 df&.!7_R`
begin gy"<[N
.?c
insert into test (userid) values(@i) U~oGg$
set @i=@i+1 [Y^h)k{-$
end 9{IDw
小记存储过程中经常用到的本周,本月,本年函数 q&LCMnv"P
Dateadd(wk,datediff(wk,0,getdate()),-1) r,P`$-
Dateadd(wk,datediff(wk,0,getdate()),6) NT9| ``^Z
Dateadd(mm,datediff(mm,0,getdate()),0) NGW:hgf
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Fn{Pmo*rs
Dateadd(yy,datediff(yy,0,getdate()),0) KD--w(4
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2_)gJ_kP
上面的SQL代码只是一个时间段 @H}Hjg_>m
Dateadd(wk,datediff(wk,0,getdate()),-1) ? ^`fPH=
Dateadd(wk,datediff(wk,0,getdate()),6) nt%p@e!,
就是表示本周时间段. Hv%$6,/ *v
下面的SQL的条件部分,就是查询时间段在本周范围内的: V$dhiP
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Epm8S}6K
而在存储过程中 #IU^(W
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 6S0Gjekr
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) y8}
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