如何构建并打印到浏览器类别树？

Question

So I want to build a category script for products.

How I can build the category tree?

I have a DB like this...

CREATE TABLE categories (
    cat_id integer GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
    parent_id integer NOT NULL,
    cat_name CHAR(24) NULL DEFAULT NULL,
    cat_position tinyint NOT NULL,
    icon TEXT NULL DEFAULT NULL,
    keywords text NOT NULL, //for search
    active boolean NULL DEFAULT true,
    cat_description CHAR(128) NULL DEFAULT NULL
);

But I can't understand how it works because 1 product may be found in many categories...

I am coding on GoLang

Now I do like this...

rows, err := db.Query("SELECT cat_id, parent_id, cat_name FROM categories WHERE active = true ORDER BY Parent_id ASC")
if err != nil {
    http.Error(w, http.StatusText(500), 500)
    return
}
defer rows.Close()

Then I put rows into template...

{{range .}}
<p><a href="/show?getinfo={{ .Cat_id}}">{{ .Cat_id}}</a> - {{ .Parent_id}} - {{ .Cat_name}} <a href="/show?getinfo={{ .Cat_id}}">Показать</a>
{{end}}

In the end I would like to get something similar to this