Mysql2 ::错误：操作数应包含1列（S）

Question

这条线在我的控制器：

Mysql2::Error: Operand should contain 1 column(s): SELECT `feedbacks`.* FROM `feedbacks` WHERE (reviewer_id = 1, reviewee_id = 10, strength_id = 0) LIMIT 1 

Answer 1

我觉得你的SQL：

@feedback = Feedback.where("reviewer_id = ?, reviewee_id = ?, strength_id = ?", current_user.id, @report_for.id, @context).first 

，当我尝试显示@feedback.something产生这个错误是错的，试试这个

@feedback = Feedback.where("reviewer_id = ? and reviewee_id = ? and strength_id = ?", current_user.id, @report_for.id, @context).first