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Student(S#,Sname,Sage,S***) ѧÉú±í
Course(C#,Cname,T#) ¿Î³Ì±í
SC(S#,C#,score) ³É¼¨±í
Teacher(T#,Tname) ½Ìʦ±í
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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;
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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
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select count(distinct(Tname))
from Teacher
where Tname like 'Àî%';
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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');
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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');
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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”¿
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aaa,bbb
ccc,ddd
eee,fff
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load data
infile 'c:\loader.txt'
append
into table tester.mm(
m1 position(1:3) char,
m2 position(5:7) char)
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sqlldr tester/test control=c:\loade ......
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SELECT osuser, username, sql_text from v$session a, v$sqltext b
where a.sql_address =b.address order by address, piece;
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analyze table tablename compute statistics for all indexes;
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select count(card), card from TableName group by card having count(card) > 1
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ColumnName type not null constraint FK_Name foreign key(ColumnName) references PrimaryTable(ColumnName) on update/delete cascade
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id classid,score
1 01 120
2 01 128
3 02 98
4 04 134
5 04 78
ÏÖÔÚҪͳ¼Æ ¸÷°àscore >120,ºÍ´óÓÚ90·ÖµÄÈËÊý
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classid >120 >90
01 &nb ......