Question

如何让GROUP CONCAT运算符中的WHERE依赖于查询中的另一列？在这种情况下，需要发生的是score_list的值取自相关候选人的分数。在MySQL中，我能够通过使用别名（SELECT candidate_id作为id .... WHERE scores.candidate_id = id ...）来使用它，在SQLite中我得到“没有这样的列”。

SELECT candidate_id, 
        first_name || ' ' || last_name AS 'name',
        (
            SELECT GROUP_CONCAT(score) 
            FROM scores 
            WHERE scores.candidate_id = *NEEDS TO BE CANDIDATE_ID* 
                AND scores.category_id = 1 
            ORDER BY scores.judge_id
        ) AS score_list
FROM scores 
    JOIN candidates 
        ON candidates.id = scores.candidate_id

Answer 1

尝试对表格进行别名处理。

SELECT oute.candidate_id, 
        oute.first_name || ' ' || oute.last_name AS 'name',
        (
            SELECT GROUP_CONCAT(inne.score) 
            FROM scores inne
            WHERE inne.candidate_id = oute.candidate_id
                AND inne.category_id = 1 
            ORDER BY inne.judge_id
        ) AS score_list
FROM scores oute 
    JOIN candidates 
        ON candidates.id = oute.candidate_id

SQLite SELECT查询 - 基于另一列的值的GROUP CONCAT列

1 个答案: