50¸ö³£ÓÃsqlÓï¾ä
Student(S#,Sname,Sage,Ssex) ѧÉú±í
Course(C#,Cname,T#) ¿Î³Ì±í
SC(S#,C#,score) ³É¼¨±í
Teacher(T#,Tname) ½Ìʦ±í
ÎÊÌ⣺
1¡¢²éѯ“001”¿Î³Ì±È“002”¿Î³Ì³É¼¨¸ßµÄËùÓÐѧÉúµÄѧºÅ£»
select a.S# from (select s#,score from SC where C#='001') a,(select s#,score
from SC where C#='002') b
where a.score>b.score and a.s#=b.s#;
2¡¢²éѯƽ¾ù³É¼¨´óÓÚ60·ÖµÄͬѧµÄѧºÅºÍƽ¾ù³É¼¨£»
select S#,avg(score)
from sc
group by S# having avg(score) >60;
3¡¢²éѯËùÓÐͬѧµÄѧºÅ¡¢ÐÕÃû¡¢Ñ¡¿ÎÊý¡¢×ܳɼ¨£»
select Student.S#,Student.Sname,count(SC.C#),sum(score)
from Student left Outer join SC on Student.S#=SC.S#
group by Student.S#,Sname
4¡¢²éѯÐÕ“ÀÄÀÏʦµÄ¸öÊý£»
select count(distinct(Tname))
from Teacher
where Tname like 'Àî%';
5¡¢²éѯûѧ¹ý“Ҷƽ”ÀÏʦ¿ÎµÄͬѧµÄѧºÅ¡¢ÐÕÃû£»
select Student.S#,Student.Sname
from Student
where S# not in (select distinct( SC.S#) from SC,Course,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='Ҷƽ');
6¡¢²éѯѧ¹ý“001”²¢ÇÒҲѧ¹ý±àºÅ“002”¿Î³ÌµÄͬѧµÄѧºÅ¡¢ÐÕÃû£»
select Student.S#,Student.Sname from Student,SC where Student.S#=SC.S# and SC.C#='001'and exists( Select * from SC as SC_2 where SC_2.S#=SC.S# and SC_2.C#='002');
7¡¢²éѯѧ¹ý“Ҷƽ”ÀÏʦËù½ÌµÄËùÓпεÄͬѧµÄѧºÅ¡¢ÐÕÃû£»
select S#,Sname
from Student
where S# in (select S# from SC ,Course ,Teacher where SC.C#=Course.C# and Teacher.T#=Course.T# and Teacher.Tname='Ҷƽ' group by S# having count(SC.C#)=(select count(C#) from Course,Teacher where Teacher.T#=Course.T# and Tname='Ҷƽ'));
8¡¢²éѯ¿Î³Ì±àºÅ“002”µÄ³É¼¨±È¿Î³Ì±àºÅ“001”¿Î³ÌµÍµÄËùÓÐͬѧµÄѧºÅ¡¢ÐÕÃû£»
Select S#,Sname from (select Student.S#,Student.Snam
Ïà¹ØÎĵµ£º
Maximizing SQL*Loader Performance
SQL*Loader is flexible and offers many options that should be considered to maximize the speed of data loads. These include:
¡ñ Use Direct Path Loads - The conventional path loader essentially loads the data by usin ......
ÔÚÎÒÃÇ×öÊý¾Ý¿â³ÌÐò¿ª·¢µÄʱºò£¬¾³£»áÓöµ½ÕâÖÖÇé¿ö£ºÐèÒª½«Ò»¸öÊý¾Ý¿â·þÎñÆ÷ÖеÄÊý¾Ýµ¼Èëµ½ÁíÒ»¸öÊý¾Ý¿â·þÎñÆ÷µÄ±íÖС£Í¨³£ÎÒÃÇ»áʹÓÃÕâÖÖ·½·¨£ºÏȰÑÒ»¸öÊý¾Ý¿âÖеÄÊý¾ÝÈ¡³öÀ´·Åµ½Ä³³ö£¬È»ºóÔÙ°ÑÕâЩÊý¾ÝÒ»ÌõÌõ²åÈ뵽ĿµÄÊý¾Ý¿âÖУ¬ÕâÖÖ·½·¨Ð§Âʽϵͣ¬Ð´Æð³ÌÐòÀ´Ò²ºÜ·±Ëö£¬ÈÝÒ׳ö´í¡£ÁíÍâÒ»ÖÖ·½·¨ÊÇʹÓÃbcp»òBULK IN ......
Ó¦ÓÃʾÀý£º
-- ´´½¨2¸ö²âÊÔ±í
CREATE TABLE [dbo].[Table_2019]([Data] [nchar](2019) NOT NULL)
CREATE TABLE [dbo].[Table_2020]([Data] [nchar](2020) NOT NULL)
go
-- Ìî³äÊý¾Ý
declare @i int
set @i = 0
while(@i < 20)
begin
insert Table_2019(Data) values('')
  ......
Èç¹ûÄãÕýÔÚ¸ºÔðÒ»¸ö»ùÓÚSQL ServerµÄÏîÄ¿£¬»òÕßÄã¸Õ¸Õ½Ó´¥SQL Server£¬Äã¶¼ÓпÉÄÜÒªÃæÁÙһЩÊý¾Ý¿âÐÔÄܵÄÎÊÌ⣬ÕâÆªÎÄÕ»áΪÄãÌṩһЩÓÐÓõÄÖ¸µ¼£¨ÆäÖдó¶àÊýÒ²¿ÉÒÔÓÃÓÚÆäËüµÄDBMS£©¡£
ÔÚÕâÀÎÒ²»´òËã½éÉÜʹÓÃSQL ServerµÄÇÏÃÅ£¬Ò²²»ÄÜÌṩһ¸ö°üÖΰٲ¡µÄ·½°¸£¬ÎÒËù×öµÄÊÇ×ܽáһЩ¾Ñé----¹ØÓÚÈçºÎÐγÉÒ»¸öºÃµÄÉè¼Æ¡£Õ ......
ͨ¹ýË÷Òý£¬¿ÉÒÔ¼Ó¿ìÊý¾ÝµÄ²éѯËٶȺͼõÉÙϵͳµÄÏìӦʱ¼ä£»¿ÉÒÔʹ±íºÍ±íÖ®¼äµÄÁ¬½ÓËٶȼӿ졣µ«ÊÇ£¬²»ÊÇÔÚÈκÎʱºòʹÓÃË÷Òý¶¼Äܹ»´ïµ½ÕâÖÖЧ¹û¡£ÈôÔÚ²»Ç¡µ±µÄ³¡ºÏÏ£¬Ê¹ÓÃË÷Òý·´¶ø»áÊÂÓëԸΥ¡£ Ë÷ÒýÊÇÒÔ±íÁÐΪ»ù´¡µÄÊý¾Ý¿â¶ÔÏó¡£Ë÷ÒýÖб£´æ×űíÖÐÅÅÐòµÄË÷ÒýÁÐ
¡¡¡¡
ͨ¹ýË÷Òý£¬¿ÉÒÔ¼Ó¿ìÊý¾ÝµÄ²éѯËٶȺͼõÉÙϵͳµÄÏìӦʱ¼ä£ ......