Check if field exists in CosmosDB JSON with SQL - nodeJS

All you need to do is change your query to

SELECT r.id, r.authToken.instagram,r.userName FROM root r WHERE r.abc != null

or

SELECT r.id, r.authToken.instagram,r.userName FROM root r WHERE r.abc <> null

Both operators work (tested on the Data Explorer)

Add the NOT operator in the SQL query to negate.

SELECT r.id, r.authToken.instagram,r.userName 
FROM root r 
WHERE NOT IS_DEFINED(r.abc)

to include all entries where the FieldName abc doesn't exist.

If you want to know if a field exists you should use the IS_DEFINED("FieldName") If you want to know if the field's value has a value the FieldName != null or FieldName <> null (apparently)

I use variations of this in production:

SELECT c.FieldName
FROM c 
WHERE IS_DEFINED(c.FieldName)