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。 Huw\&E
4wzlJ19E(
`D7C?M#j]
一、基础 #(Or|\t
1、说明:创建数据库 Id'RL2Kq*&
CREATE DATABASE database-name T<yP* b2E
2、说明:删除数据库 l|`9:H
drop database dbname zZ-wG
3、说明:备份sql server -a Gcf]6
--- 创建 备份数据的 device f},oj4P\
USE master ^he=)rBb?
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' >M!xiQX
--- 开始 备份 _GQz!YA
BACKUP DATABASE pubs TO testBack +eX)48
4、说明:创建新表 S&C1 TC
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X8eJ4%
根据已有的表创建新表: A?Q a 4i
A:create table tab_new like tab_old (使用旧表创建新表) 3q[WHwmm
B:create table tab_new as select col1,col2... from tab_old definition only W|k0R4K]]
5、说明:删除新表 ~%u|[$
drop table tabname ChryJRuwv5
6、说明:增加一个列 hlZ@Dq%f
Alter table tabname add column col type UAF<m1
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。 n@C~ev@%S
7、说明:添加主键: Alter table tabname add primary key(col) W)j|rz.
说明:删除主键: Alter table tabname drop primary key(col) ?eV(1Fr@
8、说明:创建索引:create [unique] index idxname on tabname(col....) .V9e=yW!*
删除索引:drop index idxname zboF
1v`
注:索引是不可更改的,想更改必须删除重新建。 fJ*:{48
9、说明:创建视图:create view viewname as select statement hw_JDv+
删除视图:drop view viewname r5&I?
0
10、说明:几个简单的基本的sql语句 \b'xt
选择:select * from table1 where 范围 inPJ2uBD\^
插入:insert into table1(field1,field2) values(value1,value2) C) QKPT
删除:delete from table1 where 范围 EY`H}S!xy
更新:update table1 set field1=value1 where 范围 g_*T?;!.U
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8?t"C_>*e
排序:select * from table1 order by field1,field2 [desc] /NT[ETMk+
总数:select count as totalcount from table1 O[17";P
求和:select sum(field1) as sumvalue from table1 s}&bJ"!Z
平均:select avg(field1) as avgvalue from table1 RIM`omM
最大:select max(field1) as maxvalue from table1 g o5]<4`r
最小:select min(field1) as minvalue from table1 d&cU*
SQsSa1
%,@vWmn
R`Aj|C
z
11、说明:几个高级查询运算词 wCs3:@UH
~cAZB9Fa
ub0zJTFJ#
A: UNION 运算符 k@>\LR/v
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。 yDb'7(3-
B: EXCEPT 运算符 >e5 *prx+
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。 !U_K&f
C: INTERSECT 运算符 -
N>MBn
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。 gMWBu~;!
注:使用运算词的几个查询结果行必须是一致的。 AEmNHO@%q
12、说明:使用外连接 >M%\T}5
A、left outer join: ^da44Qqu
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。 &Wp8u#4L
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 S,fCV~Cio?
B:right outer join: F1;lQA*7K.
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。 3T\l]? z
C:full outer join: `"yxdlXA
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。 y #f
QPR
:_<_[Y]1
ukgAI<O%
二、提升 zHWSE7!
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?B@;QjhjiJ
法一:select * into b from a where 1<>1 mN`YuR~
法二:select top 0 * into b from a P47V:E%
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) @ufo$?D
insert into b(a, b, c) select d,e,f from b; [@<sFP;g
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) >$67 7
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 >t,M
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. %1
KbS
[
4、说明:子查询(表名1:a 表名2:b) ?)Nj c&G
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) djQv[Vc{
5、说明:显示文章、提交人和最后回复时间 ]e:/"
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b E! /[gZ
6、说明:外连接查询(表名1:a 表名2:b) QR?yG+VU
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c )CPM7>
7、说明:在线视图查询(表名1:a ) JG`Q;K
select * from (SELECT a,b,c FROM a) T where t.a > 1; <E;pgw!
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 seFGJfN\?f
select * from table1 where time between time1 and time2 =-cwXo{Q.O
select a,b,c, from table1 where a not between 数值1 and 数值2 zo{/'BnU
9、说明:in 的使用方法 EqiFy"H
select * from table1 where a [not] in ('值1','值2','值4','值6') O-vGyNxP|
10、说明:两张关联表,删除主表中已经在副表中没有的信息 sML=5=otx
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ,ea^,H6
11、说明:四表联查问题: m .IU ;cR
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 ..... _i_Q?w`
12、说明:日程安排提前五分钟提醒 '[|+aJ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 zr v]
13、说明:一条sql 语句搞定数据库分页 x} /,yaWZ
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 uhH^>z
KA
14、说明:前10条记录 Zd^6ulx
select top 10 * form table1 where 范围 \ b
V6@#,
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.) yfQ5:X
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) z@|dzvjl
Q
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 'z@ 0
(select a from tableA ) except (select a from tableB) except (select a from tableC) ha@L94Lq
17、说明:随机取出10条数据 @tohNO>
select top 10 * from tablename order by newid() "|Fy+'5}
18、说明:随机选择记录 0Q,g7K<d
select newid() }uHrto3M
19、说明:删除重复记录 iF5'ygR-Z
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) c:S] R"
20、说明:列出数据库里所有的表名 W+wA_s2&D
select name from sysobjects where type='U' zQ?!f#f
21、说明:列出表里的所有的 'mCe=Y
select name from syscolumns where id=object_id('TableName') 2=0DCF;Bv
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。 A,-6|&F
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 ;a=w5,h:
显示结果: ?PA$Ur21lw
type vender pcs K`&oC8p
电脑 A 1 N/YWb y=H
电脑 A 1 6h?gs"[j
光盘 B 2 CfEmT8sa
光盘 A 2 CHd9l]Rbe
手机 B 3 I3 =#@2
手机 C 3 X5fmz%VK@
23、说明:初始化表table1 HjvCujJ
TRUNCATE TABLE table1 ~I/@i
24、说明:选择从10到15的记录 M}:=zcZ l
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc +;BAV
exh/CK4;
|Z\R*b"
N- e$^pST
三、技巧 wHZW `
1、1=1,1=2的使用,在SQL语句组合时用的较多 @Q&3L~K"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, I
+5)Jau^S
如: )M=ioE8`h
if @strWhere !='' I&?Qq k
begin Xdi:1wW@p
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ;Mm7n12z C
end 7A\Cbu2tf
else 7g=2Z[o
begin k$5 s{q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' f:*vr['d
end G)#$]diNuX
我们可以直接写成 1"8yLvtn
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere :(dHY
2、收缩数据库 a8u9aEB
--重建索引 J]W5[)L
DBCC REINDEX &uP~rEJl+
DBCC INDEXDEFRAG o)6p A^+
--收缩数据和日志 h1 WT
DBCC SHRINKDB nKR{ug>I)
DBCC SHRINKFILE ?oZR.D|SZ
3、压缩数据库 qbrp P(.
dbcc shrinkdatabase(dbname) WPZ?*Sx
4、转移数据库给新用户以已存在用户权限 (npj_s!.C)
exec sp_change_users_login 'update_one','newname','oldname' 5tJ,7Y'
go kP#e((f,
5、检查备份集 A,su;Qh
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' i'd2[A.7I
6、修复数据库 KKA~#iCk
ALTER DATABASE [dvbbs] SET SINGLE_USER |r
ue=QZ
GO {NpM.;
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK AE: Z+rM*
GO r|4t aV&
ALTER DATABASE [dvbbs] SET MULTI_USER j Ja$a [
GO Nu8Sr]p
7、日志清除 =_j vk.
SET NOCOUNT ON FYs)MO
DECLARE @LogicalFileName sysname, Vz14j_
@MaxMinutes INT, %1pYEHn
@NewSize INT "~UUx"Y
USE tablename -- 要操作的数据库名 -(#I3h;I
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 EM>}0V
@MaxMinutes = 10, -- Limit on time allowed to wrap log. jq'!UN{
@NewSize = 1 -- 你想设定的日志文件的大小(M) HW&%T7
a
-- Setup / initialize &DqE{bBd!
DECLARE @OriginalSize int dd2[yKC`
SELECT @OriginalSize = size Y|8vO
FROM sysfiles \xg]oKbn
WHERE name = @LogicalFileName "5cM54Z0
SELECT 'Original Size of ' + db_name() + ' LOG is ' + k6`6Mjbc
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + L
lqM c
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' (F7(^.MG
FROM sysfiles \~P=U;l=pO
WHERE name = @LogicalFileName B?VhIP e
CREATE TABLE DummyTrans sLE#q+W
(DummyColumn char (8000) not null) 2r$#m*
DECLARE @Counter INT, A+@&"
@StartTime DATETIME, rt
JtK6t
@TruncLog VARCHAR(255) H>r!i4l
SELECT @StartTime = GETDATE(), 3_JCU05H}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' TW !&p"Us+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) (&$VxuJ+6y
EXEC (@TruncLog) !lo/xQ<
-- Wrap the log if necessary. }b 1cLchl
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired CJ}5T]WZ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) G0E121`h
AND (@OriginalSize * 8 /1024) > @NewSize ,C3,TkA]
BEGIN -- Outer loop. }kg ye2[
SELECT @Counter = 0 u!1{Vt87
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) M$f7sx
BEGIN -- update O25lLNmO
INSERT DummyTrans VALUES ('Fill Log') 8* Jw0mSw
DELETE DummyTrans 8H[:>;SI
SELECT @Counter = @Counter + 1 S/;bU:
END R_=6GZH$G
EXEC (@TruncLog) zB yqD$
END -i-? .:
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Z{'i F
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + tTd\|
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' |bgo;J/
FROM sysfiles bLt.O(T}
WHERE name = @LogicalFileName boG_f@dv(
DROP TABLE DummyTrans 1+?N#Fh
SET NOCOUNT OFF "RIZV
8、说明:更改某个表 fNGZ o
exec sp_changeobjectowner 'tablename','dbo' <w3!!+oK"
9、存储更改全部表 Z"unF9`"1
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch g^zs,4pPU<
@OldOwner as NVARCHAR(128), fhB}9i^]tg
@NewOwner as NVARCHAR(128) 0p89: I*0
AS UA|u U5Q
DECLARE @Name as NVARCHAR(128) 1}~(Yj@f%
DECLARE @Owner as NVARCHAR(128) 4Qn$9D+?
DECLARE @OwnerName as NVARCHAR(128) 'vN G(h#%d
DECLARE curObject CURSOR FOR )8g(:`w
select 'Name' = name, A$6$,h
'Owner' = user_name(uid) \d::l{VB
from sysobjects @JdZ5Q
where user_name(uid)=@OldOwner Haqm^Ky$
order by name >:lnt /N3
OPEN curObject hB{jUP)";
FETCH NEXT FROM curObject INTO @Name, @Owner K\|FQ^#UYm
WHILE(@@FETCH_STATUS=0) Ar~"R4!
BEGIN HaIM#R32T
if @Owner=@OldOwner qWw\_S
begin sVex
(X
set @OwnerName = @OldOwner + '.' + rtrim(@Name) b86}% FM
exec sp_changeobjectowner @OwnerName, @NewOwner k{t`|BnPKB
end I}R0q
-- select @name,@NewOwner,@OldOwner P;4w*((} ~
FETCH NEXT FROM curObject INTO @Name, @Owner nB .G
END [=~ pe|8:
close curObject vTn}*d.K=
deallocate curObject iYC9eEF
GO \l~*PG2
10、SQL SERVER中直接循环写入数据 V^;jJ']
declare @i int s=CK~+,/
set @i=1 w6j/ Dq!
while @i<30 ']+Uu'a
begin ?IpLf\n-
insert into test (userid) values(@i) (W}bG>!#Q8
set @i=@i+1 k1Q?'<`
end j&k6O1_
小记存储过程中经常用到的本周,本月,本年函数 0Fu~%~#E$
Dateadd(wk,datediff(wk,0,getdate()),-1) 4>J
Dateadd(wk,datediff(wk,0,getdate()),6) y+7PwBo%e
Dateadd(mm,datediff(mm,0,getdate()),0) '(/7[tJ
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) yr,=.?C-
Dateadd(yy,datediff(yy,0,getdate()),0) Sfdu`MQR
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) *g^x*|f6
上面的SQL代码只是一个时间段 ,i@X'<;y
Dateadd(wk,datediff(wk,0,getdate()),-1) +@r*}
Dateadd(wk,datediff(wk,0,getdate()),6) f5 `g
就是表示本周时间段. kwsp9 0)
下面的SQL的条件部分,就是查询时间段在本周范围内的: 4bgqg0z>
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) J`2"KzR0w"
而在存储过程中 )m. 4i =X
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 7B?c{
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Pi|o` d