Php mysql子查询中的限制

我对MySQL语句有问题

我有这个：

SELECT ad.*, 
  (SELECT img.image 
   FROM '.$this->config->db_prefix.'_images AS img 
   WHERE img.aid = ad.aid LIMIT 1) AS img 
FROM '.$this->config->db_prefix.'_adverts ad 
WHERE fid = :fid 
ORDER BY cr_date DESC

这很好，但我需要从

\u images

表中获取所有图像，因此如果我删除

LIMIT 1

，我将获得

Cardinality violation: 1242 Subquery returns more than 1 row

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SQL的结果作为JSON输出。

您遇到的问题是，当您说select时，mysql希望一次得到一个条目。看看mysql连接语句

您可以使用MySQL聚合函数：

SELECT ad.*, (SELECT GROUP_CONCAT(img.image) FROM '.$this->config->db_prefix.'_images AS img WHERE img.aid = ad.aid) AS img FROM '.$this->config->db_prefix.'_adverts ad WHERE fid = :fid ORDER BY cr_date DESC

然后在php或javascript中使用它

SELECT ad.*, (SELECT GROUP_CONCAT(img.image) FROM '.$this->config->db_prefix.'_images AS img WHERE img.aid = ad.aid) AS img FROM '.$this->config->db_prefix.'_adverts ad WHERE fid = :fid ORDER BY cr_date DESC