mysql重点题目–查询“01“课程比“02“课程成绩高的学生的信息及课程分数

– 1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数

我的答案:

select 
st.*,
sc.s_score '语文',
sc2.score2 '数学',
inner join score sc on sc.s_id =st.s_id and sc.c_id='01'
inner join score sc2 on sc2.s_id =st.s_id and sc2.c_id='02'
where sc.s_score> sc2.s_score

标准答案:

SELECT  
st.*,
sc.s_score AS '语文',
sc2.s_score AS '数学'

FROM
student st
LEFT JOIN score sc ON sc.s_id=st.s_id AND sc.c_id='01'
LEFT JOIN score sc2 ON sc2.s_id=st.s_id AND sc2.c_id='02'
WHERE sc.s_score>sc2.s_score