![database - While doing aggregation in MongoDB in lookup pipeline the id field is not available to perform match - Stack Overflow database - While doing aggregation in MongoDB in lookup pipeline the id field is not available to perform match - Stack Overflow](https://i.stack.imgur.com/YQ23j.png)
database - While doing aggregation in MongoDB in lookup pipeline the id field is not available to perform match - Stack Overflow
![database - While doing aggregation in MongoDB in lookup pipeline the id field is not available to perform match - Stack Overflow database - While doing aggregation in MongoDB in lookup pipeline the id field is not available to perform match - Stack Overflow](https://i.stack.imgur.com/Lnb6T.png)
database - While doing aggregation in MongoDB in lookup pipeline the id field is not available to perform match - Stack Overflow
![Aggregation with transactional data should return unique value only - Working with Data - MongoDB Developer Community Forums Aggregation with transactional data should return unique value only - Working with Data - MongoDB Developer Community Forums](https://www.mongodb.com/community/forums/uploads/default/original/3X/2/1/21296289bb89ca8cad22dff1d5e57f70ad71e074.png)