$expr query is not working in IDE and it works in Atlas collection

For lab $expr question: How many companies in the sample_training.companies collection have the same permalink as their twitter_username?

When i enter a query in IDE :

db.companies.find (
{ 
    $expr:  { $eq: ["$permalink", "$twitter_username"] }
}
).count()

It shows the result as 0.

When i enter the same query in Atlas collections filter :

{"$expr":{"$eq":["$permalink","$twitter_username"]}}

It shows many results.

can someone help me with this issue I don't understand why am i getting this issue.

Most likely you are not using sample_training database.

Show the output of the 2 commands below from inside the IDE.

db
db.companies.find().count()
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MongoDB Enterprise atlas-8z9ka2-shard-0:PRIMARY> db.companies.find().count()
9500
MongoDB Enterprise atlas-8z9ka2-shard-0:PRIMARY> db
sample_training
MongoDB Enterprise atlas-8z9ka2-shard-0:PRIMARY>

Then, have you tried your query?

It works. As said below, make sure, you use the right collections.

can you tell me the answer plz?, in mine it’s showing 0 as the output

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