得到的question和answer是json格式，字段是map<string,string>，需要将序号和后面的问题或者答案分开，采用lateral view explode的方法，lateral view explode和explode相比，可以select 非炸裂的字段
要注意炸裂后的两个字段不用括号，如果有where，where放在最后面
select q_key, q_value
from questionnaire
lateral view explode(questions) t as q_key, q_value可以多次使用lateral view explode
select q_key, q_value, a_key, a_value
from questionnaire
lateral view explode(questions) t as q_key, q_value
lateral view explode(answers) t2 as a_key, a_value
where q_key=a_key