Question

我试图通过收集id的数组来将数据渲染到样条图表上：

控制器

def student_feedback
        difficulty_ids = current_user.school_user.homework_students.pluck(:difficulty)
        @homeworks = HomeworkStudent.where("homework_id = (?)", difficulty_ids).first
    end

在我的图表中：

...
       }
        },
        series: [{
            name: 'Difficulty',
            data: [<%= @homeworks.to_json %>]
        }]
    });

但我一直收到这个错误：

Mysql2::Error: Operand should contain 1 column(s): SELECT `homework_students`.* FROM `homework_students` WHERE (homework_id = (4,2,1,2,3)) ORDER BY `homework_students`.`id` ASC LIMIT 1

收集的数据是正确的。这只是一个语法错误吗？我玩了一下。从＆＃34; homework_id =？＆＃34;中删除括号给出相同的结果......如果需要可以提供更多代码。

由于

谢谢@ the12

试过这个

def student_feedback
        difficulty_ids = current_user.school_user.homework_students.pluck(:difficulty)
        @homeworks = HomeworkStudent.where(["homework_id = ?", difficulty_ids]).first
    end

但这会返回错误`

Mysql2::Error: Operand should contain 1 column(s): SELECT `homework_students`.* FROM `homework_students` WHERE (homework_id = 4,2,1,2,3) ORDER BY `homework_students`.`id` ASC LIMIT 1`

如果它说homework_id = 4,2,1 ......这些数字实际上来自一个名为＆＃34;难度＆＃34; - 也许在控制器上面的陈述中有些东西是关闭的？

Answer 1

只是读取SQL错误.. difficulty_ids是一个数组，由它产生的SQL语句证明：

 WHERE (homework_id = 4,2,1,2,3)

从homework_id = difficulty_ids开始，它是一个数组。您必须确保homework_id仅等于where子句中的单个数字。

MySQL，Highcharts：＆＃34;操作数应包含1列：＆＃34;错误

1 个答案: