Mysql 索引不生效

Question

SELECT
    od.origin_amount,
    o.id,
    od.id,
    od.course_id,
    od.assign_user_id 
FROM
    easyway_order o
    LEFT JOIN easyway_order_detail od ON od.order_id = o.id

SELECT
    wpd.id,
    wpd.min,
    wp.id,
    wp.`name`,
    wp.work_type,
    wp.order_type obj_type 
FROM
    easyway_wage_project wp
    LEFT JOIN easyway_wage_project_detail wpd ON wpd.project_id = wp.id

很疑惑 不知道为啥 ，同样在 非主键字段都有索引

Answer 1

你看看表easyway_wage_project_detail是否有index或者id是否有主键