find with or operation in mongodb code example

Example 1: find with $or in mongobd

db.inventory.find( { $or: [ { quantity: { $lt: 20 } }, { price: 10 } ] } )

Example 2: and operation mongodb find

db.inventory.find( { $and: [ { price: { $ne: 1.99 } }, { price: { $exists: true } } ] } )