要确保被解析的字段是string类型才可以使用json解析.解析map类型不能使用json解析，解析map类型可以使用col_name['key']获取对应key的value.
lateral view：如果指定字段名则需要把lateral view查询出的列写到select中，才能在结果中出现；如果直接是select * 则自动会把lateral view查询出的列追加在后面。
select * from sales_info where dt = '2019-04-26'
----------------------------
select *,
get_json_object(state, '$.id') as id,
get_json_object(state, '$.token') as token,
get_json_object(state, '$.user_name') as user_name
from sales_info where dt = '2019-04-26';
----------------------------
select *
from sales_info
lateral view json_tuple(state,'id','token','user_name') state_json as id,token,user_name
where dt = '2019-04-26';
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