如何在嵌套的row_to_json中传递键名

Question

我正在查询我的postgresql 9.6数据库，并从Node服务器中生成json输出。我已经开始工作了，除了我的属性名称“ col1Name”和“ col2Name”被删除并替换为f1和f2。我在网上找到有关使用子查询保留键名的信息（例如“从（从表中选择col1，从表中选择col2，选择col1，从表t选择col1，col2）”），但我无法弄清楚如何在此代码段中做到这一点。我认为嵌套有误，但我眼花cross乱。

var query = "SELECT row_to_json(fc) FROM ( " +
        "SELECT 'FeatureCollection' As type, array_to_json(array_agg(f)) As features FROM (" +
            "SELECT 'Feature' As type, ST_AsGeoJSON(fg.geom)::json As geometry, " +
            "row_to_json((col1Name, col2Name)) As properties FROM myTable As fg" +
       ") As f" +
    ") As fc";