What is order by child in Firebase?

By default, a query retrieves all documents that satisfy the query in ascending order by document ID. You can specify the sort order for your data using orderBy() , and you can limit the number of documents retrieved using limit() .24 Eyl 2021

When using orderByChild() , data that contains the specified child key is ordered as follows: Children with a null value for the specified child key come first. Children with a value of false for the specified child key come next. If multiple children have a value of false , they are sorted lexicographically by key.

By default, all the nodes are ordered by key . One thing to remember is that Firebase keys are Strings . And when strings are order, are ordered lexicographically .