Question

好的，所以我有一个很好的小查询返回得分结果。该查询目前基于LIKE，我想将其转换为everyone keeps告诉我的全文查询。如果不是相同的分数，我想得到相同的结果顺序。我能够获得任何接近的唯一方法是展开我的交叉连接...

我希望能够设置特定单词组合的分数
我希望能够根据找到术语的位置设置权重
我不希望根据搜索中的Power Set字词进行搜索。也就是说，如果用户输入“铁路员工”，我不想在任何时候搜索“员工”。我试图仅从查询中搜索连续的术语分组。

如何使我的原始查询以全文为基础并保持相对较小且有条理？

您可以在SQLFiddle上看到这两个查询。

原始查询 - 很好，很小，分数和搜索字词都是一次性的

SELECT
  sum(score * multiplier) score,
  a.id,
  a.title
FROM
(
  SELECT 3 score, 'a railway employee' term UNION ALL
  SELECT 2 score, 'railway employee' term UNION ALL
  SELECT 2 score, 'a railway' term UNION ALL
  SELECT 1 score, 'employee' term UNION ALL
  SELECT 1 score, 'railway' term UNION ALL
  SELECT 0 score, 'a' term
) terms
CROSS JOIN
(
  SELECT 'T' TYPE, 1 multiplier
  UNION ALL SELECT 'S', 1.1
  UNION ALL SELECT 'C', 1.5
) x
INNER JOIN
(
  SELECT id, 'T' TYPE, title SEARCH FROM articles
  UNION ALL
  SELECT id, 'S' TYPE, summary SEARCH FROM articles WHERE summary <> ''
  UNION ALL
  SELECT artId, 'C' TYPE, content SEARCH FROM articleSections
) s ON s.TYPE = x.TYPE AND SEARCH LIKE concat('%', terms.term, '%')
INNER JOIN articles a ON a.id = s.id
WHERE score > 0
GROUP BY id, title
ORDER BY score DESC, title;
;

全文 - 凌乱而大，分数和搜索字词都到处都是

SELECT
  sum(score * multiplier) score,
  id,
  title
FROM
(
SELECT
  3 score,
  1 multiplier,
  'T' AS loc,
  id,
  title
FROM articles
WHERE MATCH(title) AGAINST ('"a railway employee"' IN BOOLEAN MODE)
UNION ALL
SELECT
  2 score,
  1 multiplier,
  'T' AS loc,
  id,
  title
FROM articles
WHERE MATCH(title) AGAINST ('"railway employee"' IN BOOLEAN MODE)
UNION ALL
SELECT
  2 score,
  1 multiplier,
  'T' AS loc,
  id,
  title
FROM articles
WHERE MATCH(title) AGAINST ('"a railway"' IN BOOLEAN MODE)
UNION ALL
SELECT
  1 score,
  1 multiplier,
  'T' AS loc,
  id,
  title
FROM articles
WHERE MATCH(title) AGAINST ('railway' IN BOOLEAN MODE)
UNION ALL
SELECT
  1 score,
  1 multiplier,
  'T' AS loc,
  id,
  title
FROM articles
WHERE MATCH(title) AGAINST ('employee' IN BOOLEAN MODE)
UNION ALL


SELECT
  3 score,
  1 multiplier,
  'S' AS loc,
  id,
  title
FROM articles
WHERE MATCH(summary) AGAINST ('"a railway employee"' IN BOOLEAN MODE)
UNION ALL
SELECT
  2 score,
  1.1 multiplier,
  'S' AS loc,
  id,
  title
FROM articles
WHERE MATCH(summary) AGAINST ('"railway employee"' IN BOOLEAN MODE)
UNION ALL
SELECT
  2 score,
  1.1 multiplier,
  'S' AS loc,
  id,
  title
FROM articles
WHERE MATCH(summary) AGAINST ('"a railway"' IN BOOLEAN MODE)
UNION ALL
SELECT
  1 score,
  1.1 multiplier,
  'S' AS loc,
  id,
  title
FROM articles
WHERE MATCH(summary) AGAINST ('railway' IN BOOLEAN MODE)
UNION ALL
SELECT
  1 score,
  1.1 multiplier,
  'S' AS loc,
  id,
  title
FROM articles
WHERE MATCH(summary) AGAINST ('employee' IN BOOLEAN MODE)
UNION ALL


SELECT
  3 score,
  1.5 multiplier,
  'C' AS loc,
  id,
  title
FROM articleSections
INNER JOIN articles a ON a.id = artId
WHERE MATCH(content) AGAINST ('"a railway employee"' IN BOOLEAN MODE)
UNION ALL
SELECT
  2 score,
  1.5 multiplier,
  'C' AS loc,
  id,
  title
FROM articleSections
INNER JOIN articles a ON a.id = artId
WHERE MATCH(content) AGAINST ('"railway employee"' IN BOOLEAN MODE)
UNION ALL
SELECT
  2 score,
  1.5 multiplier,
  'C' AS loc,
  id,
  title
FROM articleSections
INNER JOIN articles a ON a.id = artId
WHERE MATCH(content) AGAINST ('"a railway"' IN BOOLEAN MODE)
UNION ALL
SELECT
  1 score,
  1.5 multiplier,
  'C' AS loc,
  id,
  title
FROM articleSections
INNER JOIN articles a ON a.id = artId
WHERE MATCH(content) AGAINST ('railway' IN BOOLEAN MODE)
UNION ALL
SELECT
  1 score,
  1.5 multiplier,
  'C' AS loc,
  id,
  title
FROM articleSections
INNER JOIN articles a ON a.id = artId
WHERE MATCH(content) AGAINST ('employee' IN BOOLEAN MODE)

) t
WHERE score > 0
GROUP BY id, title
ORDER BY score DESC, title;
;

Answer 1

评论太长了。

显然，您有非常具体的评分需求，既不是搜索的自然语言模式也不是搜索的布尔模式。我想知道MySQL中是否存在一些隐藏机制，它会为您提供搜索关键字匹配列表，然后您可以将其用于评分。我不知道。

如果你有一个大的语料库和相对罕见的单词（意味着你要找的单词在相对较少的文档中），那么你可以使用布尔模式来减少搜索空间。这样的查询看起来像：

select t.id, sum(terms.score * wherefactor.factor)
from (select t.*
      . . .
      where MATCH(title, summary, content) AGAINST ('railway employee' IN BOOLEAN MODE)
     ) t left outer join
     (SELECT 3 score, 'a railway employee' term UNION ALL
      SELECT 2 score, 'railway employee' term UNION ALL
      SELECT 2 score, 'a railway' term UNION ALL
      SELECT 1 score, 'employee' term UNION ALL
      SELECT 1 score, 'railway' term UNION ALL
      SELECT 0 score, 'a' term
    ) terms cross join
    (SELECT 'T' as which, 1.0 as factor UNION ALL
     SELECT 'S', 1.1 UNION ALL
     SELECT 'C', 1.5
    ) wherefactor
    on (case when wherefacctor.which = 'T' then title 
             when wherefactor.which = 'S' then subject
             when wherefactor.which = 'C' then content
        end) like concat('%', term, '%')
group by t.id;

这应该为您提供全文搜索的性能以及评分算法的细节。

如果你有一个已知的词典，另一种可能性就是建立一个文档术语表。这样的表对于每个文档都有一行，并且文档中的每个术语都是您关心的（这称为“词典”）。有了这样的数据结构，您就可以自由地实现您选择的任何分数机制。

将MySQL LIKE查询转换为全文查询

1 个答案: