Get the highest answer rate question from a table survey_log with these columns:
uid, action, question_id, answer_id, q_num,
timestamp.
uid means user id; action has these kind of values: "show", "answer", "skip"; answer_id is not null when action column is "answer", while is null for "show" and "skip"; q_num is the numeral order of the question in current session.
Write a sql query to identify the question which has the highest answer rate.
Example:
Input: +------+-----------+--------------+------------+-----------+------------+ | uid | action | question_id | answer_id | q_num | timestamp | +------+-----------+--------------+------------+-----------+------------+ | 5 | show | 285 | null | 1 | 123 | | 5 | answer | 285 | 124124 | 1 | 124 | | 5 | show | 369 | null | 2 | 125 | | 5 | skip | 369 | null | 2 | 126 | +------+-----------+--------------+------------+-----------+------------+ Output: +-------------+ | survey_log | +-------------+ | 285 | +-------------+ Explanation: question 285 has answer rate 1/1, while question 369 has 0/1 answer rate, so output 285.
Note: The highest answer rate meaning is: answer number's ratio in show number in the same question.