Question

我正在构建一个搜索页面，其中表单将变量传递给SQL查询。如果我输入任何搜索参数，我得到我想要的结果，除非我将作者或主题搜索留空，如果有多个作者和/或主题与结果相关，我将得到多个结果。我的大多数记录都有多位作者或多个科目。

基本问题是如果有一个记录有2位作者和3个相关科目，那么我得到6个结果。

我想要实现的目标：我正在尝试修改查询，以便我只收到一条记录（record_ID是唯一的），即使有多个作者或多个科目。

我遇到问题的查询中的2个JOINS是拉动作者和主题。例如，为了获得作者，我使用这个连接（主题JOIN几乎相同），变量$ fauthor从php传递：

SELECT la.author, la.author_ID, ra.record_ID
FROM lib_author AS la
JOIN record_author AS ra ON la.author_ID = ra.author_ID
JOIN lib_record AS lr ON ra.record_ID = lr.record_ID
WHERE la.author LIKE '%$fauthor%'

关联的表是lib_author [author_ID，author]，lib_record [record_ID，...]和record_author [record_ID，author_ID]

以下是完整的查询：

select a.record_ID, a.year, n.title, y.author, y.author_ID, j.journal, pox.publisher, lox.language, a.volume, a.issue, a.pages, a.abstract, s.subject
   FROM lib_record AS a  
   JOIN lib_title as n on n.title_ID = a.title_ID
   JOIN (SELECT la.author, la.author_ID, ra.record_ID
       FROM lib_author AS la
       JOIN record_author AS ra ON la.author_ID = ra.author_ID
       JOIN lib_record AS lr ON ra.record_ID = lr.record_ID
            WHERE la.author LIKE '%$fauthor%') AS y 
   JOIN (SELECT ls.subject, ls.subject_ID, rs.record_ID 
        FROM lib_subject AS ls
        JOIN record_subject AS rs ON ls.subject_ID = rs.subject_ID
        JOIN lib_record AS lr ON rs.record_ID = lr.record_ID
            WHERE ls.subject LIKE '%$fsubject%') AS s
   JOIN lib_journal AS j on j.journal_ID = a.journal_ID
   JOIN lib_publisher pox ON a.publisher_ID = pox.publisher_ID
   JOIN lib_language lox ON a.language_ID = lox.language_ID
   WHERE y.record_ID = a.record_ID 
   AND s.record_ID = a.record_ID
   AND n.title LIKE '%$ftitle%'
   AND j.journal LIKE '%$fjournal%'

我希望有人有一些见解。感谢

Answer 1

我相信你只想按record_ID对结果进行分组。使用更简单的查询：

SELECT la.author, la.author_ID, ra.record_ID
  FROM lib_author AS la
  JOIN record_author AS ra ON la.author_ID = ra.author_ID
  JOIN lib_record AS lr ON ra.record_ID = lr.record_ID
  WHERE la.author LIKE '%$fauthor%'
  GROUP BY ra.record_ID

这将获取la。*的 last 条目。如果您想要以逗号分隔的作者列表，可以使用group_concat（）。

Answer 2

这是最后添加GROUP BY的最终查询，并且GROUP_CONCAT添加到作者和主题JOINS以显示完整的数据集。感谢@Doug Kress的帮助！我只是一名志愿者网站管理员：

select a.record_ID, a.year, n.title, GROUP_CONCAT(DISTINCT y.author SEPARATOR '; ') AS author, y.author_ID, j.journal, pox.publisher, lox.language, a.volume, a.issue, a.pages, a.abstract, GROUP_CONCAT(DISTINCT s.subject SEPARATOR '; ') AS subject
   FROM lib_record AS a  
   JOIN lib_title as n on n.title_ID = a.title_ID
   JOIN (SELECT la.author, la.author_ID, ra.record_ID
       FROM lib_author AS la
       JOIN record_author AS ra ON la.author_ID = ra.author_ID
       JOIN lib_record AS lr ON ra.record_ID = lr.record_ID
            WHERE la.author LIKE '%$fauthor%') AS y 
   JOIN (SELECT ls.subject, ls.subject_ID, rs.record_ID 
        FROM lib_subject AS ls
        JOIN record_subject AS rs ON ls.subject_ID = rs.subject_ID
        JOIN lib_record AS lr ON rs.record_ID = lr.record_ID
            WHERE ls.subject LIKE '%$fsubject%') AS s
   JOIN lib_journal AS j on j.journal_ID = a.journal_ID
   JOIN lib_publisher pox ON a.publisher_ID = pox.publisher_ID
   JOIN lib_language lox ON a.language_ID = lox.language_ID
   WHERE y.record_ID = a.record_ID 
   AND s.record_ID = a.record_ID
   AND n.title LIKE '%$ftitle%'
   AND j.journal LIKE '%$fjournal%' 
   GROUP BY a.record_ID

MySQL查询显示多个结果

2 个答案: