翻译查询

Question

我有一个MySQL表翻译。现在我正在搜索一个查询，该查询返回与给定语言列表匹配的第一个翻译:

假设一个字符串有4种翻译:

id          lang     translation
--------------------------------
greeting    en       hey!
greeting    de       Hallo.
greeting    de_at    Servus!
greeting    de_ch    Grüezi

根据给定语言列表查询的期望结果:

language list    result
-----------------------
de,en            Hallo.
en,de            hey!
de_at,de,en      Servus!

这在单个查询中可能吗?

Answer 1

SELECT COALESCE( de_at.translation, de.translation, en.translation )
  FROM (SELECT 'greeting' AS id) AS id
  LEFT JOIN translations AS de_at ON( de_at.lang = 'de_at' AND id.id = de_at.id )
  LEFT JOIN translations AS de ON( de.lang = 'de' AND id.id = de.id )
  LEFT JOIN translations AS en ON( en.lang = 'en' AND id.id = en.id )

Answer 2

试试这个:

SELECT * FROM translations t WHERE id = 'greeting' AND lang IN ('de_at', 'de', 'en') ORDER BY FIELD(lang, 'de_at', 'de', 'en') LIMIT 1