How to Use Where Clause in Firestore

1import { getFirestore, collection, query, where, getDocs } from 'firebase/firestore'
2
3const db = getFirestore()
4
5// Exact match
6const activeUsersQuery = query(
7  collection(db, 'users'),
8  where('status', '==', 'active')
9)
10
11// Range comparison
12const expensiveProductsQuery = query(
13  collection(db, 'products'),
14  where('price', '>', 100)
15)
16
17const snapshot = await getDocs(activeUsersQuery)
18snapshot.forEach((doc) => {
19  console.log(doc.id, doc.data())
20})

1// Match any of these categories
2const categoriesQuery = query(
3  collection(db, 'products'),
4  where('category', 'in', ['electronics', 'clothing', 'books'])
5)
6
7// Exclude specific statuses
8const nonDraftQuery = query(
9  collection(db, 'posts'),
10  where('status', 'not-in', ['draft', 'archived'])
11)

1// Find posts tagged with 'firebase'
2const firebasePostsQuery = query(
3  collection(db, 'posts'),
4  where('tags', 'array-contains', 'firebase')
5)
6
7// Find posts tagged with any of these
8const multiTagQuery = query(
9  collection(db, 'posts'),
10  where('tags', 'array-contains-any', ['firebase', 'react', 'typescript'])
11)

1// Compound equality — no composite index needed
2const adminActiveQuery = query(
3  collection(db, 'users'),
4  where('role', '==', 'admin'),
5  where('status', '==', 'active')
6)
7
8// Equality + range — requires composite index
9const recentElectronicsQuery = query(
10  collection(db, 'products'),
11  where('category', '==', 'electronics'),
12  where('price', '<', 500),
13  where('price', '>', 50)
14)

1import { query, where, orderBy, limit, collection } from 'firebase/firestore'
2
3const topElectronicsQuery = query(
4  collection(db, 'products'),
5  where('category', '==', 'electronics'),
6  orderBy('price', 'asc'),
7  limit(10)
8)
9
10// Range filter requires orderBy on the same field first
11const recentExpensiveQuery = query(
12  collection(db, 'products'),
13  where('price', '>', 100),
14  orderBy('price', 'desc'),
15  orderBy('createdAt', 'desc'),
16  limit(20)
17)

1import { query, where, collection, onSnapshot } from 'firebase/firestore'
2
3const activeOrdersQuery = query(
4  collection(db, 'orders'),
5  where('status', '==', 'pending')
6)
7
8const unsubscribe = onSnapshot(activeOrdersQuery, (snapshot) => {
9  snapshot.docChanges().forEach((change) => {
10    if (change.type === 'added') {
11      console.log('New pending order:', change.doc.data())
12    }
13    if (change.type === 'removed') {
14      console.log('Order no longer pending:', change.doc.id)
15    }
16  })
17})
18
19// Call unsubscribe() when done to stop listening