gorm 中left join的使用

使用mysql语句执行时可以执行成功，但是使用go语言编程保存到struct中时出现问题。

代码如下：

sflog.Debug("QueryByTaskId ", id)

    type Data struct {

        TaskId          int64   `json:"taskId"`

        VehicleName     string  `json:"vehicleName"`

        VehicleElec     float64 `json:"vehicleElec"`

        VehicleNumber   string  `json:"vehicleNumber"`

        VehicleLocation int64   `json:"vehicleLocation"`

        VehicleStatus   int     `json:"vehicleStatus"`

    }

    var datas []Data

    joinQuery := mu.DB.Table("job j").Select("j.business_id AS taskId, a.name AS vehicleName, s.battery AS vehicleElec, j.agv_serial_no AS vehicleNumber, s.node_id AS vehicleLocation, s.state AS vehicleStatus").

        Joins("LEFT join agv a on a.serial_no = j.agv_serial_no").

        Joins("LEFT JOIN agv_state s on s.business_id = a.agv_state_id").

        Where("j.business_id=?", id)

    if err = joinQuery.Debug().Find(&datas).Error; err != nil {

        sflog.Errorf("query job table err:%v ", err.Error())

    }

    sflog.Debug("datas: ", datas)

 

执行语句后datas是null的。后面改为这个语句，执行ok

 

    joinQuery := mu.DB.Table("job j").Select("j.business_id AS task_id, a.name AS vehicle_name, s.battery AS vehicle_elec, j.agv_serial_no AS vehicle_number, s.node_id AS vehicle_location, s.state AS vehicle_status").

        Joins("LEFT join agv a on a.serial_no = j.agv_serial_no").

        Joins("LEFT JOIN agv_state s on s.business_id = a.agv_state_id").

        Where("j.business_id=?", id)