sql - 复杂的 Postgres SQL 到 RoR ORM

Question

环境：RoR 3.2 + Postgres

我创建了一个services具有 2 个文本属性的表：title和description

我要操作以下全文搜索：

SELECT * FROM (
        SELECT DISTINCT ON (s.id) s.*, 
            ts_rank_cd(s.service_tsv, query) AS rank 
        FROM to_tsquery('red | drawing | fun') AS query, 
            services AS s
        WHERE (s.service_tsv @@ query)
        ORDER BY s.id DESC
) AS sub ORDER BY rank DESC;

SQL 语句就像一个魅力，但我如何将其转换为 Rails ORM：

Service.joins(???).where(???).uniq 

Answer 1

Service.find_by_sql(%q{SELECT * FROM (
        SELECT DISTINCT ON (s.id) s.*, 
            ts_rank_cd(s.service_tsv, query) AS rank 
        FROM to_tsquery('red | drawing | fun') AS query, 
            services AS s
        WHERE (s.service_tsv @@ query)
        ORDER BY s.id DESC
) AS sub ORDER BY rank DESC})

此处指南http://guides.rubyonrails.org/active_record_querying.html#finding-by-sql