sql×ܽá
1.´´½¨Êý¾Ý¿â
--exec xp_cmdshell 'mkdir d:\project'--µ÷ÓÃDOSÃüÁî´´½¨Îļþ¼Ð£¬Ê¹Óô˾äÐèÒªÆô¶¯SQLµÄÍâΧ¹¤¾ß
if exists(select * from sysdatabases where name='Êý¾Ý¿âÃû')
drop database Êý¾Ý¿âÃû
set nocount on --È¡ÏûÊÜÓ°ÏìÐÐÊý
create database Êý¾Ý¿âÃû
on
(
name='',
filename='',-- .mdf .ldf
size=10mb,
maxsize=
filename= --Êý¾Ý¿â´óСÔö³¤Á¿
)
log on
(
)
go
use Êý¾Ý¿âÃû
--´´½¨µÇ¼Óû§
exec sp_addlogin 'Óû§Ãû','ÃÜÂë'
--È¥µôÊÜÓ°ÏìÐÐÊý
set nocount on
exec sp_grantdbaccess 'adminMaster','adminMaster'
--ÉèÖÃÓû§¶Ô±íµÄȨÏÞ
grant select,delete,update on bbstopic to Óû§Ãû
2.´´½¨±í¼°Ìí¼ÓÔ¼Êø
create table ±í
(
)
alter table ±í add
constraint Ô¼ÊøÃû primary key(ÁÐÃû) --Ö÷¼üÔ¼Êø identity
constraint Ô¼ÊøÃû check(len(ÁÐÃû)) --checkÔ¼Êø
constraint Ô¼ÊøÃû unique(ÁÐÃû) --Î¨Ò»Ô¼Êø
constraint Ô¼ÊøÃû default(ĬÈÏÄÚÈÝ) for ÁÐÃû
constraint Ô¼ÊøÃû foreign key(Íâ¼üÃû)
references Ö÷¼üÊý¾Ý¿âÃû(Ö÷¼üÃû)
ck£ºcheckÔ¼Êø
fk£ºÍâ¼üÔ¼Êø
df£ºdefaultĬÈÏ
×¢£ºalter ¸Ä±ä, ¸ü¸Ä
add ¼ÓÈ룬 Ôö¼Ó, Ìí¼Ó
constraint Ç¿ÖÆ£¬ÏÞÖÆ, Ô¼Êø
foreign key Íâ¼ü
references ÒýÓÃ
3.sqlÖеĹؼü×Ö£º
sysdatabases ×Ü¿â
exists ÅжÏÊÇ·ñ´æÔÚ
Ïà¹ØÎĵµ£º
Oracle ¶¯Ì¬SQL·µ»Øµ¥Ìõ½á¹ûºÍ½á¹û¼¯
1. DDL ºÍ DML
/**//*** DDL ***/
begin
EXECUTE IMMEDIATE 'drop table temp_1';
EXECUTE IMMEDIATE 'create table temp_1(name varchar2(8))';
end;
/**//*** DML ***/
declare
v_1 varchar2(8);
& ......
£¨18£©ÓÃEXISTSÌæ»»DISTINCT£º
µ±Ìá½»Ò»¸ö°üº¬Ò»¶Ô¶à±íÐÅÏ¢(±ÈÈ粿ÃűíºÍ¹ÍÔ±±í)µÄ²éѯʱ,±ÜÃâÔÚSELECT×Ó¾äÖÐʹÓÃDISTINCT¡£Ò»°ã¿ÉÒÔ¿¼ÂÇÓÃEXISTÌæ»», EXISTS ʹ²éѯ¸üΪѸËÙ,ÒòΪRDBMSºËÐÄÄ£¿é½«ÔÚ×Ó²éѯµÄÌõ¼þÒ»µ©Âú×ãºó,Á¢¿Ì·µ»Ø½á¹û¡£Àý×Ó£º
(µÍЧ):
SELECT DISTINCT DEPT_NO,DEPT_NAME  ......
µÍЧ: (Ë÷ÒýʧЧ)
SELECT … from DEPARTMENT WHERE DEPT_CODE IS NOT NULL;
¸ßЧ: (Ë÷ÒýÓÐЧ)
SELECT … from DEPARTMENT WHERE DEPT_CODE >=0;
£¨27£©×ÜÊÇʹÓÃË÷ÒýµÄµÚÒ»¸öÁУº
Èç¹ûË÷ÒýÊǽ¨Á¢ÔÚ¶à ......
l INNER JOIN
ÄÚÁ¬½ÓÊÇ×î³£¼ûµÄÒ»ÖÖÁ¬½Ó£¬ËüÒ³±»³ÆÎªÆÕͨÁ¬½Ó£¬¶øE.FCodd×îÔç³ÆÖ®Îª×ÔÈ»Á¬½Ó¡£
ÏÂÃæÊÇANSI SQL£92±ê×¼
select * from t_institution i
inner join t_teller t
on i.inst_no = t.inst_no //˵Á½¸ö±íÖ®¼äµÄ¹ØÏµÓÃON
where i.inst_no = "5801"
ÆäÖÐinner¿ÉÒÔʡ ......