Question

我正在使用全文搜索搜索3个不同的表，我需要检测结果来自哪个表。这就是我现在所拥有的：

SELECT id, title AS page_title, MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score FROM pages WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) UNION
SELECT id, title AS agenda_title, MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score FROM agenda WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) UNION
SELECT id, title AS news_title, MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score FROM news WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) ORDER BY score ASC

我正在检测是否已设置page_title，如果没有设置议程标题等。但结果始终来自第一个查询（页面）。因此，如果访问者搜索并查找新闻项，则在这种情况下它将显示为页面。

所以我的问题是;我究竟做错了什么？这是最好的方法吗？

提前致谢！

Answer 1

尝试查询：

SELECT 'pages' AS used_table,id, title, MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score FROM pages WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) UNION
SELECT 'agenda' AS used_table,id, title , MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score FROM agenda WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) UNION
SELECT 'news' AS used_table,id, title , MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score FROM news WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) ORDER BY score ASC

并检查used_table字段以检查使用了巫婆表。

Answer 2

当您使用UNIONs时，请为每个表添加一个行列式列，只是一个常量，以便您知道每个条目来自哪个表。

SELECT source, id, title, score
    FROM
    (SELECT 'pages' AS source, id, title, MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score
        FROM pages WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE)
    UNION
    SELECT 'agenda' AS source, id, title, MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score 
        FROM agenda WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) UNION
    SELECT 'news' AS source, id, title, MATCH(title) AGAINST(:search_term IN BOOLEAN MODE) AS score 
        FROM news WHERE MATCH(title) AGAINST(:search_term IN BOOLEAN MODE)
) ORDER BY score ASC

你还需要在整个组合集中将它包装在SELECT到ORDER BY中，就像我想的那样只能在最后一个表上排序。更改title属性也不是一个好主意，因为UNION的列名必须相同，否则它会将它们与第一个遇到的标题合并，或者只删空列名。 / p>

在全文搜索上检索受影响的表

2 个答案: