ON子句中的另一个未知列名称错误

Question

查询：

SELECT  c.title AS title
            , c.introtext AS body
            , c.state AS state
            , c.created AS created
            , c.created_by AS uid
            , c.modified AS modified
            , c.modified_by AS modified_uid
            , c.published AS published
            , c.published_by AS published_uid
            , jos_categories.title AS category
FROM
          jos_content AS c, jos_categories
INNER JOIN jos_categories AS jc
ON c.sectionid = jc.section
WHERE c.sectionid = 7

我确定sectionid列存在，但我收到错误：

  

错误代码：1054。'on'中的未知列'c.sectionid'   条款'0.000秒

我看到了这个主题：MySQL unknown column in ON clause但我也解决不了。

Answer 1

将您的FROM子句更改为：

FROM   jos_content AS c
INNER JOIN jos_categories AS jc 
ON c.sectionid = jc.section 
WHERE c.sectionid = 7 

Answer 2

您在jos_categories和jos_categories AS jc之间执行联接：

jos_content AS c, jos_categories
INNER JOIN jos_categories AS jc
ON c.sectionid = jc.section

但c是jos_content ...