Cosmos Order By

Cosmos DB is a NoSQL document database service that allows you to store and query data in a highly scalable and performant way. One of the key features of Cosmos DB is the support for different query languages, including SQL, MongoDB, Azure Table Storage, and Gremlin.

In this article, we will focus on the SQL API and specifically on the ORDER BY clause in Cosmos DB.

Understanding ORDER BY

The ORDER BY clause is a common SQL operator that allows you to sort the results of a query by one or more columns. In Cosmos DB, you can use the ORDER BY clause to sort the results of a SQL query based on the value of a specific property in the JSON documents stored in your database.

For example, let's assume that you have a container called orders that contains documents with the following structure:

{
    "id": "1",
    "customerId": "123",
    "orderDate": "2022-01-01T00:00:00.000Z",
    "totalAmount": "100"
}

To sort the orders container by the orderDate property in ascending order, you can issue the following SQL query:

SELECT * FROM orders ORDER BY orderDate ASC

This will return all documents in the orders container sorted by the orderDate property in ascending order.

Syntax

The syntax for the ORDER BY clause in Cosmos DB is as follows:

SELECT * FROM containerName ORDER BY propertyName [ASC|DESC]

• containerName: The name of the container that contains the documents you want to query.
• propertyName: The name of the property you want to sort by.
• ASC|DESC: Optional. Specifies whether to sort the results in ascending or descending order. Default is ascending.

Performance considerations

When using the ORDER BY clause in Cosmos DB, there are some performance considerations to keep in mind.

First, sorting large result sets can be a resource-intensive operation, especially if you are sorting based on a property that is not indexed. To avoid performance issues, make sure that you have created appropriate indexes on the properties you are sorting by.

Second, the ORDER BY clause is not supported for queries that have a TOP operator or an OFFSET operator with a LIMIT operator. This is because sorting a subset of the results requires reading all results, which can be an expensive operation.

Conclusion

In conclusion, the ORDER BY clause in Cosmos DB allows you to sort the results of a SQL query based on the value of a specific property in the JSON documents stored in your database. To ensure optimal performance, make sure that you have created appropriate indexes on the properties you are sorting by and avoid using the ORDER BY clause with queries that have a TOP operator or an OFFSET operator with a LIMIT operator.