How to insert json field into mysql

I am trying to insert a json field into mysql. Its giving an error.Need your help here.

My sample code class

type StringInterfaceMap map[string]interface{}

type Movie struct {
	Id           int
	Name         string
	Casting      StringInterfaceMap
	Language     string
	Release_date time.Time
	Rating       float32
	IsAbove18    bool
}

func buildBrowserData() map[string]interface{} {
	return map[string]interface{}{
		"Actor": "Rajinikanth", "Music": "Deva",
		"resolution": struct {
			X int json:"x"
			Y int json:"y"
		}{1920, 1080},
	}
}
entry := model.Movie{
		Id:           6,
		Name:         ctx.QueryParam("Name"),
		Casting:      buildBrowserData(),
		Language:     ctx.QueryParam("Language"),
		Release_date: ctx.QueryParam("Release_date"),
		Rating:       1,
		IsAbove18:    true,
	}

When trying to insert the above entry model am getting the folowing error in inserting casting type.
converting argument type: unsupported type model.StringInterfaceMap, a map

Have the custom map type implement the driver.Valuer interface, e.g.

func (m StringInterfaceMap) Value() (driver.Value, error) {
    return json.Marshal(m)
}

And if you want to be able to also retrieve the json from the db you can implement the sql.Scanner interface, e.g.

func (m *StringInterfaceMap) Scan(src interface{}) error {
    switch data := src.(type) {
    case []byte:
        return json.Unmarshal(data, m)
    case string:
        return json.Unmarshal([]byte(data), m)
    default:
        return fmt.Errorf("unsupported type: %T", src)
    }
    return nil
}