Sort, Filter, and Order Realtime Database Queries

We may need to retrieve ordered or filtered data to use on our application. We can use the Realtime Database query function to sort data by key, value, or the child value. Similarly, the query function provides a range of options to filter data. This function takes the query instance as its first parameter, followed by a comma-separated list of query constraints to be applied.

Sort data

To sort data, we must first specify an order method. The Firebase Realtime Database provides three orderBy functions to retrieve sorted data. These are as follows:

• orderByChild: This function allows us to order queries by the values of the specified child key or the nested path.
• orderByKey: This function orders queries by their child key values.
• orderByValue: This function helps order scalar query results, such as strings, numbers, or boolean.

The code below demonstrates the initiation of the orderByChildfunction:

Note: Combining multiple orderBy calls or calling an orderBy function multiple times throws an error. Therefore, we can only use one orderBy function in the same query.