Sequelize include even if it's null

However, a where clause on a related model will create an inner join and return only the instances that have matching sub-models. To return all parent instances, you should add required: false for more detail check nested-eager-loading

var users  = require('./database/models').user;

    models.Order.findOne({
    where: {
        id: req.params.id
    },attributes: ['orderStatus','id','serviceId','orderDescription','orderScheduledDate'],
    include: [
        {model: users,required: false,
        attributes: ['firstName','phoneNumber']
        }
    ]
}).then(function(data) {

    res.status(200).send({data : data,serviceName : data["serviceId"]});

});