续集:父母至少有一个孩子

我的关系大致如下:

Parent: [id, name]
Children1: [id, parent_id, name]
Children2: [id, parent_id, name]
Children3: [id, parent_id, name]
Children4: [id, parent_id, name]

Parent 
  .hasMany -> Children1
  .hasMany -> Children2
  .hasMany -> Children3
  .hasMany -> Children4

所以，如果我这样做:

Parent->findOne({
  include: [{model: Children1}, {model: Children2}]
})

它只会将 Parent 带到有 children1 和 children2 的地方(即 Inner join).如果我这样做:

Parent->findOne({
  include: [
    {model: Children1, required: false}, 
    {model: Children2, required: false}
  ]
})