如何使用活动记录轨道的where和条件来编写

Question

如何使用活动记录轨道上的where和条件来编写此查询

SELECT c.name FROM类别as c join categories_coaches as cc on cc.category_id=c.id where cc.coach_id=16 and c.parent_id=1

Answer 1

这应该这样做：

Category.joins(:categories_coaches)
    .where('categories_coaches.id = ? AND categories.parent_id = ?', 16, 1)
    .select('categories.name')