CODEWITHSUNDEEP
javascriptnode.jsfirebasegoogle-cloud-firestore
Eduardo Ricardez
Eduardo Ricardez

Reputation: 105

Query Two Near Dates with Firestore not working

I'm making a booking chatbot and i want to know the two near availables dates to booking if one date is not available.

I had tryied with 

db.collection("horaries")
            .where("startat", "==", dateTime)
            .get()
            .then(function(querySnapshot) {
                if (querySnapshot.empty) {
                    return db.collection("horaries")
                        .where("startat", "<", dateTime)
                        .where("startat", ">", dateTime)

But it is returning empty all the time, it is work when dont have the where twice, but when i add the other where clause to make != clause it is returning empty. How can i make it work? And if this is not possible anymore, what approach can i do? i want to give the near date to expected booking date, sometimes the nearest it is on top and sometimes the nearest it is on bot so i really want to do this query.

Upvotes: 0

Views: 25

Answers (1)

Frank van Puffelen
Frank van Puffelen

Reputation: 599571

If you add multiple conditions to a query in Firestore, the conditions are combined with an AND operation. So your query is asking for horaries start before dateTime AND after dateTime. This is an empty set, because no single value can be before and after at the same time.

The common approach to get a single closest item is to combine two queries: one that queries for the first item before, and another that queries for the first item afterwards:

db.collection("horaries")
  .where("startat", "<=", dateTime)
  .get()
  .then(function(querySnapshot) {
    if (querySnapshot.empty) {
      db.collection("horaries")
        .where("startat", ">", dateTime)
        .get()
        .then(function(querySnapshot) {
          ...

As you can see, this uses the same number of queries as you already have, since I combined the equality check into the first query.

Upvotes: 1

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