postgresql - 使用别名简化 PostgreSQL 全文搜索 tsvector 和 tsquery

Question

我正在尝试简化此查询，因为它将由 PHP 动态生成，我想减少处理开销(实际查询会更长，但结构将相同!)。

SELECT title, type_name, ts_rank_cd(ARRAY[0.1,0.2,0.4,1.0],
setweight(to_tsvector(coalesce(title,'')), 'A')
||
setweight(to_tsvector(coalesce(type_name,'')), 'B')
,
to_tsquery('search & query'))
FROM TestView WHERE
setweight(to_tsvector(coalesce(title,'')), 'D')
||
setweight(to_tsvector(coalesce(type_name,'')), 'B')
@@
to_tsquery('search & query');

我希望通过定义类似于别名的东西来减少指定 tsquery 和 tsvector 两次的需要，这样就不必指定两次。像这样的东西(失败了，我不确定它是否接近正确!)

SELECT title, type_name, ts_rank_cd(ARRAY[0.1,0.2,0.4,1.0],
searchvector
,
searchquery
FROM TestView WHERE
setweight(to_tsvector(coalesce(title,'')), 'D')
||
setweight(to_tsvector(coalesce(type_name,'')), 'B') AS searchvector
@@
to_tsquery('search & query') AS searchquery;

这可能吗，还是我只是坚持生成它两次。

对于上下文，“TestView”是从多个表生成的 View 。

非常感谢任何帮助!

Answer 1

SELECT title, 
       type_name,
       ts_rank_cd(ARRAY[0.1,0.2,0.4,1.0],weight,query)
FROM (
    SELECT title, 
           type_name, 
           setweight(to_tsvector(coalesce(title,'')), 'A')
              ||setweight(to_tsvector(coalesce(type_name,'')), 'B') as weight,
           to_tsquery('search & query') as query
    FROM TestView 
) t
WHERE weight @@ query