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。 F(;jM(
nGns}\!7'
3T?f5+@I
一、基础 :6zC4Sr^
1、说明:创建数据库 ~GA8_B
CREATE DATABASE database-name &kiF/F 1
2、说明:删除数据库 >K5~:mx#3
drop database dbname 0d";Hh:
3、说明:备份sql server e6 2y
--- 创建 备份数据的 device bs
BZE
USE master Li]k7w?H
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Fe5jdV<
--- 开始 备份 \q,s?`+B
BACKUP DATABASE pubs TO testBack @0D![oA
4、说明:创建新表 >J@egIKzP
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 05"qi6tncz
根据已有的表创建新表: g}m+f]|
A:create table tab_new like tab_old (使用旧表创建新表) %E aE,
B:create table tab_new as select col1,col2... from tab_old definition only hF.6}28U1
5、说明:删除新表 K\aAM;)-
drop table tabname JN|VPvjE
6、说明:增加一个列 <XvYa{t]{
Alter table tabname add column col type JtFiFaCxY
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。 S~> 5INud
7、说明:添加主键: Alter table tabname add primary key(col) xD4$0Ppu
说明:删除主键: Alter table tabname drop primary key(col) ZtR&wk
8、说明:创建索引:create [unique] index idxname on tabname(col....) 26 ?23J
;
删除索引:drop index idxname St2Q7K5s{
注:索引是不可更改的,想更改必须删除重新建。 0E1=W6UZ
9、说明:创建视图:create view viewname as select statement `R0Y+#$8h
删除视图:drop view viewname vtZ?X';wh
10、说明:几个简单的基本的sql语句 >D~w}z/fk
选择:select * from table1 where 范围 Z(`r -}f I
插入:insert into table1(field1,field2) values(value1,value2) |(RZ/d<X\a
删除:delete from table1 where 范围 rH.gF43O:
更新:update table1 set field1=value1 where 范围 6rT4iC3Q{
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! _Z.cMYN
排序:select * from table1 order by field1,field2 [desc] D^|7#b,zcH
总数:select count as totalcount from table1 G5;V.#"Z[
求和:select sum(field1) as sumvalue from table1 Dkw*Je#6PX
平均:select avg(field1) as avgvalue from table1 Z\' wm'
最大:select max(field1) as maxvalue from table1 PtqGX=u
最小:select min(field1) as minvalue from table1 Oy%Im8.-A#
:!']p2B
'W(xgOP1
(AuPZ
11、说明:几个高级查询运算词 n/ AW?'
e3g_At\
T
.hb#oO
A: UNION 运算符 tt{`\1q
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ,Bf(r
B: EXCEPT 运算符 FT(iX`YQ
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ZV(
w
C: INTERSECT 运算符 H-2_j
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 9n 6fXOC
注:使用运算词的几个查询结果行必须是一致的。 > H~6NBd5D
12、说明:使用外连接 q]XHa ,"
A、left outer join: m8HYWzN
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 A9;0y jae
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (6clq:c7j
B:right outer join: ;'^, ,{
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 OXCQfT@\
C:full outer join: r0{]5JZt/
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 :".w{0l@
Ihqs%;V
gz4UV/qr/
二、提升 d;44;*D
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 1eD.:_t4
法一:select * into b from a where 1<>1 :<%vE !$
法二:select top 0 * into b from a @)b^^Fp
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Vo >Xp
insert into b(a, b, c) select d,e,f from b; ="3,}qR
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) Yf=FeH7"
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 h)@InYwu7
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. nB&j
4、说明:子查询(表名1:a 表名2:b) R04J3D|
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) > 0T
Za
5、说明:显示文章、提交人和最后回复时间 @[v8}D
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @RVOXkVo
6、说明:外连接查询(表名1:a 表名2:b) Q6x%
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c eT-9
7、说明:在线视图查询(表名1:a ) {(Fe7,.S3
select * from (SELECT a,b,c FROM a) T where t.a > 1; Jn#K0(FQ
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 ]
D6|o5
select * from table1 where time between time1 and time2 uw"*zBxl
select a,b,c, from table1 where a not between 数值1 and 数值2 k!owl+a
9、说明:in 的使用方法 Ia7D F'
select * from table1 where a [not] in ('值1','值2','值4','值6') c{4R*|^
10、说明:两张关联表,删除主表中已经在副表中没有的信息 U0IE1_R
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,ux+Qz5(
11、说明:四表联查问题: tl^m=(ZQ
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 ..... |7c`(.
12、说明:日程安排提前五分钟提醒 tN2 W8d
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 j3 P$@<
13、说明:一条sql 语句搞定数据库分页 eM }W6vIn
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 8[R1A
14、说明:前10条记录 m8AAp1=
select top 10 * form table1 where 范围 ]EN&S Wh
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.) $20s]ywS
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ~-<:+9m
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 g_M^E-3
(select a from tableA ) except (select a from tableB) except (select a from tableC) ~6HDW
17、说明:随机取出10条数据 e8q4O|I_
select top 10 * from tablename order by newid() >3P9 i ;W
18、说明:随机选择记录 Noz&noq
select newid() @n@g)`
19、说明:删除重复记录 VYigxhP7
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) _lT0Hu
20、说明:列出数据库里所有的表名 {:)vwUe{
select name from sysobjects where type='U' 3]`mQm E
21、说明:列出表里的所有的 /buWAX1
select name from syscolumns where id=object_id('TableName') ;($1Z7j+
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 wT/6aJoX
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ]/44Ygz/
显示结果: ?!7
SzLll
type vender pcs c,$mWTC
电脑 A 1 1Is%]6
电脑 A 1 GA@ Ue9
光盘 B 2 }#
Xi`<{
光盘 A 2 S_5?U2%D
手机 B 3 b{pg!/N4
手机 C 3 Hg whe=P
23、说明:初始化表table1 &^+3errO
TRUNCATE TABLE table1 u`6/I#q`
24、说明:选择从10到15的记录 h>W@U9
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >BJ}U_ck
|D<+X^0'
GoD ?K C
4E'|.tt(
三、技巧 k>>`fE\K
1、1=1,1=2的使用,在SQL语句组合时用的较多 \ 3G*j`
"where 1=1" 是表示选择全部 "where 1=2"全部不选, &k+*3.X
如: ev"M;"y
if @strWhere !='' JY@X2'>v/
begin g@u;Y5
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere )&z4_l8`=
end Pi){ h~B>
else L#ZLawG
begin ^aptLJF
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' zX~}]?|9
end WW6yFriuW
我们可以直接写成 (#z;(EN0t
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere !0Nf9
2、收缩数据库 }4vjKSV
--重建索引 =GTD"*vwr
DBCC REINDEX _[JkJwPTx
DBCC INDEXDEFRAG 4=s9A
--收缩数据和日志 {MxnIg7'
DBCC SHRINKDB `p1DaV
DBCC SHRINKFILE :x+ig5
3、压缩数据库 \xeVDKJH+n
dbcc shrinkdatabase(dbname) k/bque
4、转移数据库给新用户以已存在用户权限 $',3Pv
exec sp_change_users_login 'update_one','newname','oldname' ^ $wJi9D6
go ,R}Z=w#
5、检查备份集 $}4K`Iu
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' [TEcg^
6、修复数据库 Z(UD9wY5m
ALTER DATABASE [dvbbs] SET SINGLE_USER 0I^Eo|
GO cAibB&`~
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ^jOCenE3
GO `M)E* G
ALTER DATABASE [dvbbs] SET MULTI_USER ns26$bU
GO 6l[G1KkV
7、日志清除 5qiI.)
SET NOCOUNT ON xE1rxPuq)d
DECLARE @LogicalFileName sysname, k(v"B@0
@MaxMinutes INT, c _mq
@NewSize INT iokPmV
USE tablename -- 要操作的数据库名 HtUG#sc&`{
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 gn`zy9PU
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ls]H6z*q
@NewSize = 1 -- 你想设定的日志文件的大小(M) C$K+=jT
-- Setup / initialize Xl?YBZ}
DECLARE @OriginalSize int Y-]YDXrPQ
SELECT @OriginalSize = size piuKVU
FROM sysfiles doH2R@
WHERE name = @LogicalFileName o\60n
SELECT 'Original Size of ' + db_name() + ' LOG is ' + pUhc3L
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + *:j-zrwu&
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' >fbo
r'|
FROM sysfiles Qg> 0G%cXU
WHERE name = @LogicalFileName AWL[zixR
CREATE TABLE DummyTrans ~v\hIm3=m
(DummyColumn char (8000) not null) RM#fX^)=
DECLARE @Counter INT, Uz
$ @(C
@StartTime DATETIME, pw;r 25
@TruncLog VARCHAR(255) f8#*mQ
SELECT @StartTime = GETDATE(), $`v+4]
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1ys( v
DBCC SHRINKFILE (@LogicalFileName, @NewSize) O4N-_Kfp/
EXEC (@TruncLog) o$\tHzB9!A
-- Wrap the log if necessary. t\|J&4!Y
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired uOFnCy 4
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Pxk0(oBX
AND (@OriginalSize * 8 /1024) > @NewSize *`1bc'umM;
BEGIN -- Outer loop. 9t}J|09i
SELECT @Counter = 0 niQcvnT4b
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *;P2+cE>H3
BEGIN -- update /.2 qWQH
INSERT DummyTrans VALUES ('Fill Log') D2)i3vFB
DELETE DummyTrans _ .!aBy%xf
SELECT @Counter = @Counter + 1 >|(%2Zl
END z{' 6f@]
EXEC (@TruncLog) '+6<U[ L
END 5}7ISNP;f
SELECT 'Final Size of ' + db_name() + ' LOG is ' + p;e$kg1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ph
Ttx(!
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' cyHU\!Z*Zq
FROM sysfiles X\mz+al>[
WHERE name = @LogicalFileName {=6)SBjf
DROP TABLE DummyTrans x,f>X;04
SET NOCOUNT OFF 5Edo%Hd6
8、说明:更改某个表 -)6;0
exec sp_changeobjectowner 'tablename','dbo' "8?TSm8
9、存储更改全部表 hMWo\qM
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 7dHIW!OA
@OldOwner as NVARCHAR(128), W6M jQ%f
@NewOwner as NVARCHAR(128) vs\|rLa
AS jOv~!7T
DECLARE @Name as NVARCHAR(128) H@4/#V|Uy
DECLARE @Owner as NVARCHAR(128) [n!x&f8Xh
DECLARE @OwnerName as NVARCHAR(128) m\ ?\6Wk
DECLARE curObject CURSOR FOR E9L!)D]Y
select 'Name' = name, 4]IKh,jT
'Owner' = user_name(uid) k{1b20
from sysobjects |e+aZ%g
where user_name(uid)=@OldOwner Y!it!9
order by name Pr2;Kp
OPEN curObject I5Q~T5Ar
FETCH NEXT FROM curObject INTO @Name, @Owner 5v+L';wx[T
WHILE(@@FETCH_STATUS=0) ?eVj8 $BQo
BEGIN %!yxC
if @Owner=@OldOwner ~ttKI4
begin @C07k^j=U
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ", QPb3
exec sp_changeobjectowner @OwnerName, @NewOwner >HX)MwAP
end ivD^HhG
-- select @name,@NewOwner,@OldOwner $Ba`VGP>)3
FETCH NEXT FROM curObject INTO @Name, @Owner E^82==R
END "\<P$&`HA
close curObject U&s(1~e\
deallocate curObject {IrJLlq
GO G\):2Qz!|
10、SQL SERVER中直接循环写入数据 (Wn
"3
]
declare @i int FTbtAlqh<
set @i=1 4]]b1^vVj
while @i<30 @f%wd2
begin )lOji7&e
insert into test (userid) values(@i) =nw0# '
set @i=@i+1 _\!0t
end '(XW$D
小记存储过程中经常用到的本周,本月,本年函数 !YIb
Dateadd(wk,datediff(wk,0,getdate()),-1) 5c)<'EP
Dateadd(wk,datediff(wk,0,getdate()),6) YMK>+y[+4
Dateadd(mm,datediff(mm,0,getdate()),0) 9GaL0OWo
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) {n6\g]p3
Dateadd(yy,datediff(yy,0,getdate()),0) OFQ{9
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \wFhTJY
上面的SQL代码只是一个时间段 'cYQ?;
Dateadd(wk,datediff(wk,0,getdate()),-1) ze
?CoDx2
Dateadd(wk,datediff(wk,0,getdate()),6) u,\xok"
就是表示本周时间段. (c<