SQL语言——高级方法

一、原表:

courseid coursename score

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1 java 70

2 oracle 90

3 xml 40

4 jsp 30

5 servlet 80

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为了便于阅读,查询此表后的结果显式如下(及格分数为60):

courseid coursename score mark

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1 java 70 pass

2 oracle 90 pass

3 xml 40 fail

4 jsp 30 fail

5 servlet 80 pass

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写出此查询语句

select courseid, coursename ,score ,decode（sign(score-60),-1,‘fail‘,‘pass‘) as mark from course

如果score>60,sign(score-60)=1;

score==60,sign(score-60)=0;

score<60,sign(score-60)=-1;