MYSQL：基数违规：1242子查询返回超过1行？-Java 学习之路

我正在使用此查询来搜索标签相似性

SELECT sites_id
    FROM tags_to_sites
    WHERE tags_id IN (SELECT tags_id FROM tags_to_sites WHERE sites_id= ?)
    AND sites_id!= ?
    GROUP BY sites_id
    HAVING COUNT(*) = (  SELECT COUNT(*)  FROM  tags_to_sites
    WHERE tags_id IN (SELECT tags_id FROM tags_to_sites WHERE sites_id= ?)
      AND sites_id!= ?
    GROUP BY sites_id
    ORDER BY COUNT(*) DESC LIMIT 3)

但我得到一个错误

SQLSTATE [21000]：基数违规：1242子查询返回超过1行

谁知道为什么？

1 回答

正确的查询

SELECT sites_id
    FROM tags_to_sites
    WHERE tags_id IN (SELECT tags_id FROM tags_to_sites WHERE sites_id= ?)
    AND sites_id!= ?
    GROUP BY sites_id
    HAVING COUNT(*) = (  SELECT COUNT(*)  FROM  tags_to_sites
    WHERE tags_id IN (SELECT tags_id FROM tags_to_sites WHERE sites_id= ?)
      AND sites_id!= ?
    GROUP BY sites_id
    ORDER BY COUNT(*) DESC LIMIT 1)
LIMIT 3

回复于 2024-05-03T07:44:17+08:00

MYSQL：基数违规：1242子查询返回超过1行？

1 回答

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