Question

我有一个用于搜索数据库的查询。查询以代码构建，术语参数化，因此一切运行良好且安全。我这样说是因为这些术语不能来自表格，因为它们是根据搜索字段中的用户输入生成的。

一切都像它应该的那样，我只是想知道是否有更好/更快的方式来执行搜索。

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 'title' TYPE, 1 multiplier
  UNION ALL SELECT 'summary', 1.1
  UNION ALL SELECT 'detail', 1.5
) X
INNER JOIN
(
  SELECT id, 'title' TYPE, title SEARCH FROM article
  UNION ALL
  SELECT id, 'summary' TYPE, summary SEARCH FROM article WHERE summary <> ''
  UNION ALL
  SELECT artId, 'detail' TYPE, txt SEARCH FROM articleSections
) s ON s.TYPE = x.TYPE AND SEARCH LIKE concat('%', terms.term, '%')
INNER JOIN article a ON a.id = s.id
GROUP BY id, title
ORDER BY score DESC;
;

功能简单的演示在sqlfiddle上。

Answer 1

您的查询对我来说足够好了。但是，如果您愿意通过为UNION的每个部分重复连接条件来交换性能的可读性，那么您可以获得更好的执行计划：

....
INNER JOIN
(
  SELECT id, 'title' TYPE, title SEARCH FROM article
   where title like '%a railway employee%' or 
  title like '%railway employee%' 
  or title like '%a railway%'
  or title like '%employee%'
  or title like '%railway%'
  or title like '%a%'
  UNION ALL ....

优化用于搜索文章的SQL查询

1 个答案: