SQL에서 열 최대 버블 링

Question

죄송합니다 예제,하지만 뭔가가 SQL 누락되었습니다 및 나는 무엇인지 모르겠다 근본적인 믿습니다. 나는이 미친 쿼리를 가지고 ... ORDER BY 절이 없기 때문에 내부 쿼리에서

SELECT * 
    FROM (
    SELECT * 
    FROM (
    SELECT @t1 := @t1 +1 AS leaderboard_entry_youngness_rank, 1 - @t1 /100 AS 
     leaderboard_entry_youngness_based_on_expiry, leaderboard_entry . * , 
     NOW() - leaderboard_entry_timestamp AS leaderboard_entry_age_in_some_units, 
     TO_DAYS(NOW()) - TO_DAYS(leaderboard_entry_timestamp) 
     AS leaderboard_entry_age_in_days 
    FROM leaderboard_entry) AS inner_temp 
    NATURAL JOIN leaderboard 
    NATURAL JOIN user 
    WHERE (
    leaderboard_load_key = 'sk-en-adjectives-1' 
    OR leaderboard_load_key = '-sk-en-adjectives-1' 
    ) 
    AND leaderboard_quiz_mode = '0' 
    ORDER BY leaderboard_entry_age_in_some_units ASC , leaderboard_entry_timestamp ASC 
    LIMIT 0 , 100 
) AS outer_temp 
ORDER BY leaderboard_entry_elapsed_time_ms ASC , leaderboard_entry_timestamp ASC 
LIMIT 0 , 50 

I added the second nested SELECT statement because the user_name in the user table was not being returned in the outermost query. But now the leaderboard_entry_youngness_based_on_expiry field, which is being generated based on a row index ratio, is not working correctly.

If I remove the second nested SELECT statement, the leaderboard_entry_youngness_based_on_expiry works as expected, but the user_name column is not returned.

How can I satisfy both? Why is this happening?

Thanks!

This stems from the following question:

Add a numbered list column to a returned MySQL query

Answer 1

내부 SELECT 문에 user.user_name이 없으므로 username이 반환되지 않습니다. 외부 쿼리를 제거, 이전처럼 할 수 있지만,이 같은 user.user_name로 :

.... 
SELECT @t1 := @t1 +1 AS leaderboard_entry_youngness_rank, 1 - @t1 /100 AS 
    leaderboard_entry_youngness_based_on_expiry, leaderboard_entry . * , 
    NOW() - leaderboard_entry_timestamp AS leaderboard_entry_age_in_some_units, 
    TO_DAYS(NOW()) - TO_DAYS(leaderboard_entry_timestamp) 
    AS leaderboard_entry_age_in_days, user.user_name 

.... 

Answer 2

Try putting a ORDER BY이 있는데, "올바르게 작동하지 않습니다."라는 잘못된 말입니다.

외부 SELECT * FROM...을 제거했는지 확인하고 중복 된 user_name 열이 있는지 확인하십시오.

현재, 쿼리에서 행 인덱스 열을 사용하지 않으므로이 논리를 응용 프로그램 자체에 넣지 않는 이유는 무엇입니까? 더 신뢰할 수있을 것입니다.