This is going to be a short post for all the people out there who’re new to MongoDB. I had to dive into MongoDB as part of a new project that I joined. I was asked to write a Map-Reduce job, and in the process decided to run a few queries on MongoDB.

I found out that there was a $lte and a $gte operator. But no $eq operator. It baffled me that there was no way to check for equality. I searched a bit but found no option, so I used a $and operator and did a $lte AND $gte, effectively getting a $eq operator.

But now I know better. To check for equality in MongoDB, you just put the second value as the second parameter.


This checks if the field named “a” equals 123.

That’s about it. Simple, but not quite straightforward to a person fresh out of the RDBMs world and new to MongoDB :)