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，并且我想减少处理开销（真正的查询会更长，但结构将是相同的！）。

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别名的东西来尝试减少两次指定 tsquery 和 tsvector 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两次。

对于上下文“TestView”是从多个表生成的视图。

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