I have a collection of say questions like below -
{
question: "what's the question?",
answer: "some answer",
points: 10
},
{
question: "what's the question again?",
answer: "some answer again",
points: 40
},
...
The questions which are answered will have an answer in it's document and vice-versa. I want to group all the answered and not-answered questions using aggregate, to get an output like -
{
answered: [{...}, {...}],
unanswered: [{...}, {...}]
}
How would the aggregate query for this look like?
There are multiple way to do this.
One is using $facet as follows :
db.collection.aggregate([
{
"$facet": {
"answered": [
{
$match: {
answer: {
$exists: true
},
},
},
],
"unanswered": [
{
$match: {
answer: {
$exists: false
},
},
},
],
}
}
])