select distinct returns nil（globalize3）

Post.find(:all, :select => "DISTINCT author")
return
[#<Post author: nil>, #<Post author: nil>, #<Post author: nil>, #<Post author: nil>, #<Post author: nil>]。select distinct returns nil（globalize3）

但SQL請求SELECT DISTINCT author FROM posts;按預期工作。

我正在使用globalize3。 Post.select('DISTINCT author').with_translations('en')返回所有記錄。
下面是它的日誌中：

Post Load (0.5ms) SELECT "posts"."id" AS t0_r0, "posts"."description" AS t0_r1, "posts"."position" AS t0_r2, "posts"."created_at" AS t0_r3, "posts"."updated_at" AS t0_r4, "posts"."date" 
AS t0_r5, "post_translations"."id" AS t1_r0, "post_translations"."post_id" AS t1_r1, "post_translations"."locale" AS t1_r2, "post_translations"."author" 
AS t1_r3, "post_translations"."description" AS t1_r4, "post_translations"."created_at" AS t1_r5, "post_translations"."updated_at" 
AS t1_r6 FROM "posts" LEFT OUTER JOIN "post_translations" ON "post_translations"."post_id" = "posts"."id" WHERE "post_translations"."locale" = 'en' 
AND (post_translations.author IS NOT NULL)

我怎麼可以只選擇不同的值？

來源

2011-07-19 NARKOZ

請發表日誌塊用兩個請求 – Bohdan

已更新。這是第一個請求：'ActionView :: Template :: Error（No route matches {：action =>「show」，：controller =>「posts」，：id =>＃}）：' – NARKOZ

可能是這個簡單：

Post.find(:all, :group => author)

更新：

貌似Postgres的是一個小比MySQL更柔順，所以嘗試這個：

Post.select("DISTINCT ON (author) *")

來源

2011-07-19 17:26:39

'Post load（0.5ms）SELECT「posts」。* FROM「posts」WHERE（post_category_id = 1）GROUP BY作者 PGError：錯誤：列「posts.id」必須出現在GROUP BY子句中或用於彙總函數 LINE 1：SELECT「posts」。* FROM「posts」WHERE（post_category_id = 1）G ...' – NARKOZ

增加了postgres解決方案，修復了由bug –

thx組的bug， – NARKOZ

select distinct returns nil（globalize3）

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