Equality and comparison operators in Azure Cosmos DB

APPLIES TO: NoSQL

This article details the equality and comparison operators supported by Azure Cosmos DB.

Understanding equality comparisons

The following table shows the result of equality comparisons in the API for NoSQL between any two JSON types.

Op	Undefined	Null	Boolean	Number	String	Object	Array
Undefined	Undefined	Undefined	Undefined	Undefined	Undefined	Undefined	Undefined
Null	Undefined	Ok	Undefined	Undefined	Undefined	Undefined	Undefined
Boolean	Undefined	Undefined	Ok	Undefined	Undefined	Undefined	Undefined
Number	Undefined	Undefined	Undefined	Ok	Undefined	Undefined	Undefined
String	Undefined	Undefined	Undefined	Undefined	Ok	Undefined	Undefined
Object	Undefined	Undefined	Undefined	Undefined	Undefined	Ok	Undefined
Array	Undefined	Undefined	Undefined	Undefined	Undefined	Undefined	Ok

For comparison operators such as >, >=, !=, <, and <=, comparison across types or between two objects or arrays produces Undefined.

If the result of the scalar expression is Undefined, the item isn't included in the result, because Undefined doesn't equal true.

For example, the following query's comparison between a number and string value produces Undefined. Therefore, the filter does not include any results.

SELECT *
FROM c
WHERE 7 = 'a'

Next steps

• Azure Cosmos DB .NET samples
• Keywords
• SELECT clause