使用Firebase过滤列表后查询上的OrderByChild

Question

I have an Ionic mobile app that gets its data from a Firebase back end. On one page I get a list of stations with location and current price for each station. What I want to do is filter the list by location, and then order it by price.

    let query = this.db.list('/stations', {
      query: {
        orderByChild: 'distanceFromUser',
        endAt: 50.0,
        limitToFirst: 20
      }
    });

    this.stations = query, {
      query: {
        orderByChild: 'currentPrice',
      }
    }

This code is obviously not working, but it kind of displays what I would like to accomplish. First create a query with the 20 closest stations in a 50 km radius, and then order this list by currentPrice.

Is there any way to make this happen with Firebase?

Answer 1

You can try making a new child combining the two like distanceFromUser_currentPrice and then use it in the query.

Also, your query for finding 20 closest stations in a 50 km radius isn't gonna work because endAt will also return stations with distance like 150.0, 250.0 etc.