I created the following schema :
const videoSchema = createSchema(
link: Type.string({required: true}),
description: Type.string({required: true}),
answers: Type.array({required: true}).of({
text: Type.string(),
likes: Type.number()
})
);
export const videoModel = typedModel('video', videoSchema);
Now I want to write a query that only has videos with over 200 likes as a result. I've tried to work with .aggregate, $reduce and $sum, but I can't get it to work.
Does anyone know how to achieve this ? Thank you in advance!
You can try below query :
db.collection.aggregate([
/** Add a field which holds count of likes for all answers for a video */
{
$addFields: {
likesCount: {
$reduce: {
input: "$answers.likes",
initialValue: 0,
in: {
$add: [
"$$value",
"$$this"
]
}
}
}
}
},
/** filter to retain videos whose likes > 200 */
{
$match: {
likesCount: {
$gt: 200
}
}
},
/** Remove additional field from documents */
{
$project: {
likesCount: 0
}
}
])
Test : MongoDB-Playground
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