-- SELECT * FROM employment_direction_recommend_table GROUP BY student_name HAVING count(student_name)>1;
-- SELECT * FROM employment_direction_recommend_table WHERE student_name in('東青梁','桑哲青')
-- 計算平均成績及名次
SELECT a.student_name,
-- @lagfield as 上一個成績,
case when a.`平均成績`=@lagfield then @rowNum else (@rowNum:=@rowNum+1) END as `排名`,
@lagfield:=a.`平均成績` as 成績
-- (@rowNum:=@rowNum+1) as `名次`
FROM(
select student_name,
round((avg(required_synthesize)+avg(major_synthesize)+avg(synthesize_appraisal))/3,2) as `平均成績`
from employment_direction_recommend_table b GROUP BY student_name order by `平均成績` desc
) a,(SELECT (@rowNum :=0)) b,(select @lagfield:=0) r
