Let's find all the books that have the name Oliver Twist or are from Dover Publications. For the sake of brevity, we shall select only the name field as follows:
db.books.find({ $or : [ { name: "Oliver Twist"} , {publisher : "Dover Publications"} ] })
This will give us our result set of books with either the name as Oliver Twist or publisher as Dover Publications.
The previous query is similar to the following:
SELECT * FROM books WHERE publisher = "Dover Publications" OR name = "Oliver Twist";
Let's look at the query parameters in a little more detail:
{$or : [
{name: "Oliver Twist"},
{publisher : "Dover Publications"}
]
}
$or is a special operator in MongoDB and takes an array of query parameters. We can use this in conjunction with other parameters too:
db.books.find({ published_on: ISODate("2002-12-30"), $or : [ { name: "Oliver Twist"} , {publisher : "Dover Publications"} ] })
This would query with AND and OR. Its...