How to combine where clause and join? [duplicate] - sql

Question

This question already has answers here:
Multiple join conditions using the $lookup operator
(4 answers)
Closed 6 years ago.
If I were to write this in SQL it would be (sort of):
SELECT *
FROM request req, response res
WHERE req.suites_test=res.key # join
AND res.version='2.0.b1662.5' # extra conditions
AND req.suites_id='58762c40664df86d2069e2c9'
In MongoDB I can do:
# a join between request and response
db.response.aggregate([{$lookup: {from: "request", localField: "key", foreignField: "suites.test", as: "matching"} } ])
# find all requests that match a condition
db.request.find( { "suites.id": ObjectId("58762c40664df86d2069e2c9") } )
# find all responses that match a condition
db.response.find( { "version": "2.0.b1662.5" } )
How can I combine the three in a single MongoDB query?

Answer 1

There are a bunch of duplicates which are similar, but I can't find the exact matching duplicate. So, I'm adding an answer based on OP's request.
Based on your individual queries, you will just need to include the $match stage for the response ( before $lookup) and request ( after $unwind which follows $lookup ) collection in your aggregation pipeline. Something like below.
db.response.aggregate([{
$match: {
"version": "2.0.b1662.5"
}
}, {
$lookup: {
from: "request",
localField: "key",
foreignField: "suites.test",
as: "matching"
}
}, {
$unwind: "$matching"
}, {
$match: {
"matching.id": ObjectId("58762c40664df86d2069e2c9")
}
}])