Sunday, 23 April 2017

Using value of input field to filter results

I have been teaching myself web dev (using nodejs, mongodb) for a few days now and have run into a problem.

I have two tables which I need to join, followed by summing certain columns, and finally filtering (using a user specified threshold) based on the value of these sums. I do all this using aggregate pipeline.

The join and creation of columns works fine. To filter, first I create a new column, isAResult, and use match to retain the records that return true for that column. This is how I create isAResult.

 { $project: {   isAResult: {$cond: { if: {$gte: ["$totalkcal", val_kcals]}, then: true, else: false }}

where val_kcals is initiated earlier as shown below.

var val_kcals = req.body.val_kcals;

Am I missing something?



via Shashwat Mishra

No comments:

Post a Comment