Well done! In this lesson, we continued our exploration of querying in MongoDB by learning how to query array fields. Let’s recap some important takeaways from this lesson:

• We can query documents for exact array matches by using the .find() method and passing in a query document containing the field name, and its array as the value.
• We can match a single array element by using the .find() method and passing in a query document containing the field name, and the element we want to match as its value.
• To match multiple elements in an array, we can apply the $all operator to the .find() method.
• The $all operator will match any document where the given array field contains all the specified values, in any order and regardless of other elements in the array.
• We can use the .find() method with comparison operators to match documents where the array contains one or more elements that satisfy the query conditions in some combination.
• To match documents where the array contains one or more elements that satisfy all the query conditions, we can apply the $elemMatch operator to the .find() method.
• We can query embedded documents in an array field by querying for either an exact match (with the exact order) or by querying for a single field.

In addition to the syntax we’ve covered in this lesson, MongoDB provides us with even more operators that can be useful to us when querying on array fields:

• The $size operator is used with .find() to match any array with the specified number of elements.
• The $in operator can be included in queries to match documents where the field is an array that contains at least one element in the specified array.
• The $nin operator can be included in queries to match documents where the field is an array that contains no elements mentioned in the given array.