MongoDB: use $sum with multiple $cond - mongodb

Question

I want calculate points based to the size of an array element.
I can use $sum with multiple $cond?
Something like this:
{
$project: {
points: {
$sum: [
{
$cond: [
{
$and: [{ $gt: [{ $arrayElemAt: ["$matches", 0] }, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 1] }, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 2] }, 0] }],
},
10,
0,
],
},
{
$cond: [
{
$and: [{ $gt: [{ $arrayElemAt: ["$matches", 3] }, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 4] }, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 5] }, 0] }],
},
10,
0,
],
},
],
},
},
},
This script always returns 20 even if not all conditions are true
Example of document:
{
"_id" : NumberInt(5),
"total_matches" : NumberInt(0),
"matches" : [
[
],
[
],
[
],
[
],
[
],
[
],
[
],
[
],
[
]
]
}
OUTPUT
{
"_id" : NumberInt(5),
"points" : 20.0,
"matches" : [
[
],
[
],
[
],
[
],
[
],
[
],
[
],
[
],
[
]
]
}

Answer 1

Ok, the problem is that I forgot $size in the query.
The right query is this:
{
$project: {
points: {
$sum: [
{
$cond: [
{
$and: [{ $gt: [{ $size:{ $arrayElemAt: ["$matches", 0] }}, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 1] }, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 2] }, 0] }],
},
10,
0,
],
},
{
$cond: [
{
$and: [{ $gt: [{ $size:{ $arrayElemAt: ["$matches", 3] }}, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 4] }, 0] }, { $gt: [{ $arrayElemAt: ["$matches", 5] }, 0] }],
},
10,
0,
],
},
],
},
},
}