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。 XjbK!.
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一、基础 ;r']"JmF,
1、说明:创建数据库 76/%Py|
CREATE DATABASE database-name O{V"'o
2、说明:删除数据库 VrK 5a9*^
drop database dbname =g:\R$lQ
3、说明:备份sql server we9AB_y
--- 创建 备份数据的 device S0 `*
USE master nDvWOt
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' q8J/tw?%v
--- 开始 备份 %O${EN
BACKUP DATABASE pubs TO testBack @[Th{HTc.G
4、说明:创建新表 `g~-5Z~J
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) K VCS(oN
根据已有的表创建新表: T$e_ao|
A:create table tab_new like tab_old (使用旧表创建新表) ~nQb;Bdh%
B:create table tab_new as select col1,col2... from tab_old definition only EbQ} w"{
5、说明:删除新表 ^BZdR<;
drop table tabname ?kSs7e>
6、说明:增加一个列 (hoqLL\}k
Alter table tabname add column col type {`LV{!
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ]2jnY&a5
7、说明:添加主键: Alter table tabname add primary key(col) 7o<RvM
说明:删除主键: Alter table tabname drop primary key(col) R/W&~t
8、说明:创建索引:create [unique] index idxname on tabname(col....) b%BwGS(z
删除索引:drop index idxname ! [X<>
注:索引是不可更改的,想更改必须删除重新建。 |*b8-a8<
9、说明:创建视图:create view viewname as select statement *K;~V
删除视图:drop view viewname OX"`VE
10、说明:几个简单的基本的sql语句 rZEu@63
选择:select * from table1 where 范围 19S,>
插入:insert into table1(field1,field2) values(value1,value2) wa C%o%fD
删除:delete from table1 where 范围 0czy:d,M%
更新:update table1 set field1=value1 where 范围 ?2M15Q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ]WG\+1x9
排序:select * from table1 order by field1,field2 [desc] G>Q{[m$
总数:select count as totalcount from table1 G9
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求和:select sum(field1) as sumvalue from table1 "elh~K
平均:select avg(field1) as avgvalue from table1 &e(de$}xt
最大:select max(field1) as maxvalue from table1 __QTlj
最小:select min(field1) as minvalue from table1 U;(&!Ei
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11、说明:几个高级查询运算词 K"pfp !Y
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A: UNION 运算符 6V)# Yf
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。 &~j"3G;e
B: EXCEPT 运算符 V{n pK(
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。 Y/ `fPgE
C: INTERSECT 运算符 M1^pW63
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。 f /jN $p
注:使用运算词的几个查询结果行必须是一致的。 7(jt:V6V
12、说明:使用外连接 +,smjg:O
A、left outer join: ~"-wSAm
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。
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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 lY~xoHT;[
B:right outer join: mBNa;6w?{*
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。 S4 Rv6{r:
C:full outer join: e0 D;]
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。 9+L!
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二、提升 vs.q<i-u
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Sh"} c2
法一:select * into b from a where 1<>1 E_h 9y
法二:select top 0 * into b from a <'/+E4m
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Dr;@)
insert into b(a, b, c) select d,e,f from b; !_]WUQvV?
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) y"7?]#$9/
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Abj`0\
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. /_ LUys/0
4、说明:子查询(表名1:a 表名2:b) 0n1y$*I4
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) ~<|xS
5、说明:显示文章、提交人和最后回复时间 r`"
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 13B[mp4
6、说明:外连接查询(表名1:a 表名2:b) E;h#3
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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 8(BLS{-"<
7、说明:在线视图查询(表名1:a ) #fa~^]EM]
select * from (SELECT a,b,c FROM a) T where t.a > 1; md<%Z4+
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[U5SS!)
select * from table1 where time between time1 and time2 =6? 3c\
select a,b,c, from table1 where a not between 数值1 and 数值2 Y2Tg>_:t
9、说明:in 的使用方法 = uOFaZ4
select * from table1 where a [not] in ('值1','值2','值4','值6') T9u/|OP
10、说明:两张关联表,删除主表中已经在副表中没有的信息 B&tl6?7h
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 5^tL#
11、说明:四表联查问题: sR #( \
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 ..... k{9s>l~'
12、说明:日程安排提前五分钟提醒 1MOQ/N2BR
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 x3)qK6,\
13、说明:一条sql 语句搞定数据库分页 +f|u5c
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 _w(SHWh2
14、说明:前10条记录 p7|~x@q+
select top 10 * form table1 where 范围 0e3aWn
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.) Y0U:i.)
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) xAsbP$J:
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 (/c9v8Pr(7
(select a from tableA ) except (select a from tableB) except (select a from tableC) VTD'D+t
17、说明:随机取出10条数据 r lW
select top 10 * from tablename order by newid() I,.>tC
18、说明:随机选择记录 =`g+3
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select newid() U2!9Tl9".
19、说明:删除重复记录 3TO$J
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) oc>,5 x
20、说明:列出数据库里所有的表名 N-;e"
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select name from sysobjects where type='U' Haiuf)a
21、说明:列出表里的所有的 WG<D+P
select name from syscolumns where id=object_id('TableName') iYBs )
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。 h@/c76}f6p
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 N3i}>Q)B
显示结果: Hb IRE
type vender pcs p)d'yj
电脑 A 1 D@&0 P&
电脑 A 1 &R>x;&Gj
光盘 B 2 ,+%$vV
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光盘 A 2 HLa|ycB%
手机 B 3 :*#I1nb$
手机 C 3 KZJ;O7'`
23、说明:初始化表table1 :Q"]W!kCs
TRUNCATE TABLE table1 BY72 fy#e
24、说明:选择从10到15的记录 vfm|?\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc V6Z2!Ht
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三、技巧 o%5^dX&[
1、1=1,1=2的使用,在SQL语句组合时用的较多 m^% [
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Mo0+"`
如: _6(QbY'JV`
if @strWhere !='' kuqf(
begin %5NfF65'
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere s=#3f3
end *dL!)+:d
else AMGb6enl
begin :"|}oKT%mP
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' `)/G5 fB
end N{ @B@]
我们可以直接写成 0Ou`&u
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %70sS].@
2、收缩数据库 &ScADmZP^d
--重建索引 7kp$C?7K
DBCC REINDEX swntz
DBCC INDEXDEFRAG : ) SLi
--收缩数据和日志 Nl"< $/
DBCC SHRINKDB pc
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DBCC SHRINKFILE 6V
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3、压缩数据库 i"p)%q~ z
dbcc shrinkdatabase(dbname) t-)C0<
4、转移数据库给新用户以已存在用户权限
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exec sp_change_users_login 'update_one','newname','oldname' uhz:G~x!
go y+hC !-
5、检查备份集 Pq ZMuUd
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' "qYPi
6、修复数据库 SxdH%agM
ALTER DATABASE [dvbbs] SET SINGLE_USER u_[s+J/
GO &.,ZU\`zT
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 2;VggPpT
GO VImcW;Xa
ALTER DATABASE [dvbbs] SET MULTI_USER -K9bC3H
GO ^p?O1qTg
7、日志清除 RcIGIt
SET NOCOUNT ON Hr |De8#f
DECLARE @LogicalFileName sysname, 9=p^E# d
@MaxMinutes INT, S-&[Tp+N
@NewSize INT (vMC.y5
USE tablename -- 要操作的数据库名 ~3<Li}W
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 9tvLj5~
@MaxMinutes = 10, -- Limit on time allowed to wrap log. X YO09#>&
@NewSize = 1 -- 你想设定的日志文件的大小(M) g!;k$`@{E'
-- Setup / initialize ^|M\vO
DECLARE @OriginalSize int ;+t~$5
SELECT @OriginalSize = size `OO=^.-u
FROM sysfiles # Y/.%ch.
WHERE name = @LogicalFileName L8("1_
SELECT 'Original Size of ' + db_name() + ' LOG is ' + mZDL=p
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + bU9B2'%E
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 1:%HE*r
FROM sysfiles !{tkv4
WHERE name = @LogicalFileName a<9cj@h
CREATE TABLE DummyTrans |d\rCq >
(DummyColumn char (8000) not null) SV*h9LL
DECLARE @Counter INT, iTJSW
@StartTime DATETIME, *)+1BYMo
@TruncLog VARCHAR(255) N%
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SELECT @StartTime = GETDATE(), ""Nu["|E
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' YcW[BMy5h
DBCC SHRINKFILE (@LogicalFileName, @NewSize) >Q':+|K}
EXEC (@TruncLog) eq+t%
-- Wrap the log if necessary. SEsc"l8
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired <;}jf*A
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) oxT..=-
AND (@OriginalSize * 8 /1024) > @NewSize 04>dxw)8
BEGIN -- Outer loop. \-3\lZ3qj
SELECT @Counter = 0 h&d%#6mB
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) kNqSBzg
BEGIN -- update 9i4!^DM_
INSERT DummyTrans VALUES ('Fill Log') &Ohm]g8{2
DELETE DummyTrans @*SgeLeL
SELECT @Counter = @Counter + 1 Du@?j7&l=$
END Fr/3Qp@S
EXEC (@TruncLog) <%WN<T{q|
END .XD7};g
SELECT 'Final Size of ' + db_name() + ' LOG is ' + *{/
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + OL+dx`Y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $U=E7JO
FROM sysfiles ^wesuW@=
WHERE name = @LogicalFileName F&?55@b
DROP TABLE DummyTrans W'2T7ha Es
SET NOCOUNT OFF 5c50F{
8、说明:更改某个表 @pq#?
exec sp_changeobjectowner 'tablename','dbo' Ckd=tvL
9、存储更改全部表 :EOx>Pf_9)
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 3exv k
@OldOwner as NVARCHAR(128), 0uX"KL]Elf
@NewOwner as NVARCHAR(128) v^;-w~?3
AS
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DECLARE @Name as NVARCHAR(128) K"~Tk`[0Q
DECLARE @Owner as NVARCHAR(128) 27mGX\T
DECLARE @OwnerName as NVARCHAR(128) :B(F?9qK
DECLARE curObject CURSOR FOR E({+2}=1
select 'Name' = name, `m2e
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'Owner' = user_name(uid) BQYj"Wi
from sysobjects v@zpF)|
where user_name(uid)=@OldOwner Gok8:,
order by name .yz-o\,gF%
OPEN curObject |Z%I3-z_DS
FETCH NEXT FROM curObject INTO @Name, @Owner #hinb[fQ
WHILE(@@FETCH_STATUS=0) 3V")~m
BEGIN ftBbO8e
if @Owner=@OldOwner Q y(Gy'q~
begin /18Z4TA
set @OwnerName = @OldOwner + '.' + rtrim(@Name) LW?Zd=
exec sp_changeobjectowner @OwnerName, @NewOwner qyXx`'e
end ~ou1{NS
-- select @name,@NewOwner,@OldOwner ogN/zIU+VA
FETCH NEXT FROM curObject INTO @Name, @Owner BR8W8nRb
END cG|)z<Z
close curObject oK3uGPi
deallocate curObject emZ^d/A
GO *"rgK|CM$
10、SQL SERVER中直接循环写入数据 g=eYl_P6
declare @i int $'$#Xn,hU
set @i=1 $lkd9r1
while @i<30 x+~IXi>Ig
begin &cj/8A5-
insert into test (userid) values(@i) ^B9rt\,q
set @i=@i+1 ** \B P,]}
end &{ B-a
小记存储过程中经常用到的本周,本月,本年函数 Dd+ f,$
Dateadd(wk,datediff(wk,0,getdate()),-1) V\axOz!
Dateadd(wk,datediff(wk,0,getdate()),6) }5n((7@X
Dateadd(mm,datediff(mm,0,getdate()),0) ]:* 8
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) w)bLdQ
Dateadd(yy,datediff(yy,0,getdate()),0) p%304oP6
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .K![<eZ
上面的SQL代码只是一个时间段 \'(
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Dateadd(wk,datediff(wk,0,getdate()),-1) YJgw%UVJ5m
Dateadd(wk,datediff(wk,0,getdate()),6) 'BT}'qN
就是表示本周时间段. Peha{]U
下面的SQL的条件部分,就是查询时间段在本周范围内的: hjiU{@q
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) C]aa^_Ldd-
而在存储过程中 gi`K^L=C
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) a!"81*&4#
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) { .KCK_ d