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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⣺
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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#;
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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”¿Î³ÌµÍµÄËùÓÐͬѧµÄѧºÅ¡¢ÐÕÃû£»
Select S#,Sname from (select Student.S#,Student.Snam
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CASE sex
WHEN '1' THEN 'ÄÐ'
WHEN '2' THEN 'Å®'
ELSE 'ÆäËû' END
--CaseËÑË÷º¯Êý
CASE WHEN sex = '1' THEN 'ÄÐ'
  ......
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EXEC sp_configure 'c2 audit mode', '1' RECONFIGURE
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......
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CREATE TABLE tb(id int, [value] varchar(10))
INSERT tb SELECT 1, 'aa'
UNION ALL SELECT 1, 'bb'
UNION ALL SELECT 2, 'aaa'
UNION ALL SELECT 2, 'bbb'
UNION ALL SELECT 2, 'ccc'
--SELECT * from tb
/**//*
id value
----------- ----------
1 aa
1 ......
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